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3,000 | Suppose that you have an abstract for a scientific paper: we present the orbital solutions for four ob spectroscopic binaries , mt145 , gsc 03161 - 00815 , 2mass j20294666 + 4105083 , and schulte 73 , and the partial orbital solution to the b spectroscopic binary , mt372 , as part of an ongoing study to determine the distribution of orbital parameters for massive binaries in the cygnus ob2 association .
mt145 is a new , single - lined , moderately eccentric ( @xmath0 ) spectroscopic binary with period of @xmath1 days .
gsc 03161 - 00815 is a slightly eccentric ( @xmath2 ) , eclipsing , interacting and double - lined spectroscopic binary with a period of @xmath3 days .
2mass j20294666 + 4105083 is a moderately eccentric ( @xmath4 ) double - lined spectroscopic binary with a period of @xmath5 days .
schulte 73 is a slightly eccentric ( @xmath6 ) , double - lined spectroscopic binary with a period of @xmath7 days and the first `` twin '' in our survey with a mass ratio of @xmath8 .
mt372 is a single - lined , eclipsing system with a period of @xmath9 days and low eccentricity ( @xmath10 ) . of the now 18 known ob binaries in cyg ob2 , 14 have periods and mass ratios .
emerging evidence also shows that the distribution of @xmath11 is flat and consistent with `` pik s law '' . .
And you have already written the first three sentences of the full article: the study of massive binary systems in young clusters plays a key role in our understanding of how massive stars form .
in addition to providing the binary fraction for massive stars , massive binary systems provide information about their formation environment in the form of quasi - preserved parameters such as eccentricity , separation , period , and angular momentum ( in the form of rotational velocities ; * ? ? ?
in addition , an initial mass function ( imf ) composed of the secondary component masses can indicate whether the companions are randomly drawn from a @xcite ( or equivalent field star ) imf or not ..
Please generate the next two sentences of the article | this can tell us whether the binary systems may have randomly formed by way of gravitational capture after the formation process , or preferentially paired through a more complicated formation process such as competitive accretion @xcite .
cyg ob2 provides one of the best regions for indirectly examining the formation of massive stars as it houses @xmath126070 o - type stars @xcite , including an o3if ( schulte 7 ; * ? ? ? |
3,001 | Suppose that you have an abstract for a scientific paper: this is the sequel to the first paper of the series , where we have discussed the hawking radiation from five - dimensional rotating black holes for spin @xmath0 , @xmath1 and @xmath2 brane fields in the low frequency regime .
we consider the emission of a brane localized scalar field from rotating black holes in general space - time dimensions without relying on the low frequency expansions . .
And you have already written the first three sentences of the full article: black hole is one of the most important key objects in theoretical physics . though its quantum behavior and thermodynamic property have played great roles in the path to understand yet unknown quantum theory of gravity ( see e.g. refs .
@xcite ) , a direct experimental test had been believed almost impossible .
recently , the scenarios of large @xcite and warped @xcite extra dimension(s ) have led to an amazing possibility of producing black holes at future colliders with distinct signals @xcite ( see also refs ..
Please generate the next two sentences of the article | @xcite for studies before the observation @xcite that black holes radiate mainly on the brane ) . when the center - of - mass ( cm ) energy of a collision exceeds the planck scale , which is of the order of tev here , the cross section is dominated by a black hole production @xcite , which is predicted to be of the order of the geometrical one @xcite , increasing with the cm energy .
in this trans - planckian energy domain , the larger the cm energy is , the larger the mass of the resulting black hole is , and hence the better its decay is treated semi - classically via hawking radiation @xcite . |
3,002 | Suppose that you have an abstract for a scientific paper: we present observations of four t tauri stars using long baseline infrared interferometry from the palomar testbed interferometer .
the target sources , t tau n , su aur , ry tau and dr tau , are all known to be surrounded by dusty circumstellar disks .
the observations directly trace the inner regions ( @xmath01 au ) of the disk and can be used to constrain the physical properties of this material . for three of the sources observed , the infrared emission is clearly resolved .
we first use geometric models to characterize the emission region size , which ranges from 0.04 to 0.3 au in radius .
we then use monte carlo radiation transfer models of accretion disks to jointly model the spectral energy distribution and the interferometric observations with disk models including accretion and scattering . with these models , we are able to reproduce the data set with extended emission arising from structures larger than 10 milliarcseconds contributing less than 6% of the k band emission , consistent with there being little or no envelope remaining for these class ii sources ( @xmath1 -2 to 0 in the infrared ) .
the radiation transfer models have inner radii for the dust similar to the geometric models ; however , for ry tau emission from gas within the inner dust radius contributes significantly to the model flux and visibility at infrared wavelengths .
the main conclusion of our modeling is that emission from inner gas disks ( between the magnetic truncation radius and the dust destruction radius ) can be a significant component in the inner disk flux for sources with large inner dust radii . .
And you have already written the first three sentences of the full article: in the canonical model , t tauri systems comprise the central star , a rotating disk of gas and dust , a jet or outflow and possibly a residual circumstellar envelope ( see e.g. @xcite ) . in many cases ,
the central star is still accreting material and this process , as well as the mechanisms driving the outflow , are dependent on and influence the properties of the inner disk ( @xmath01 au ) .
several groups ( e.g. @xcite and @xcite ) have proposed models in which the stellar magnetic field truncates the disk at a few stellar radii ..
Please generate the next two sentences of the article | matter from the disk flows along the field lines and onto the star producing hot spots or rings that can explain observed ultraviolet photometric variability @xcite . in the last several years
, the technique of long - baseline infrared interferometry has been applied to the study of circumstellar material around young stellar objects . |
3,003 | Suppose that you have an abstract for a scientific paper: gold nanowires generated by mechanical stretching have been shown to adopt only three kinds of configurations where their atomic arrangements adjust such that either the [ 100 ] , [ 111 ] or [ 110 ] zone axes lie parallel to the elongation direction .
we have analyzed the relationship between structural rearrangements and electronic transport behavior during the elongation of au nanowires for each of the three possibilities .
we have used two independent experiments to tackle this problem , high resolution transmission high resolution electron microscopy to observe the atomic structure and a mechanically controlled break junction to measure the transport properties .
we have estimated the conductance of nanowires using a theoretical method based on the extended hckel theory that takes into account the atom species and their positions . aided by these calculations ,
we have consistently connected both sets of experimental results and modeled the evolution process of gold nanowires whose conductance lies within the first and third conductance quanta .
we have also presented evidence that carbon acts as a contaminant , lowering the conductance of one - atom - thick wires . .
And you have already written the first three sentences of the full article: the electron transport through nanometric conductors attract a huge interest due to constant shrinkage of microelectronic devices.@xcite in particular , metal nanowires ( nw ) display interesting quantum conductance behavior even at room temperature.@xcite from a practical point of view , nw s can be easily generated by putting in contact two metal surfaces , which are subsequently pulled apart . during the nw elongation and just before rupture , the conductance displays flat plateaus and abrupt jumps , which for metals such as au , take a value of approximately one conductance quantum @xmath0 = 2@xmath1 ( where @xmath2 is the electron charge and @xmath3 is planck s constant ) . in spite of the simplicity of the experimental procedure , a new structure with a different evolution
is observed for each nw generation and all conductance curves have plateaus and jumps , but they display disparate profiles.@xcite in order to overcome this difficulty , a simple statistical method has been usually applied to analyze the average behavior . instead of considering the conductance as a function of the elongation , the transport properties can be represented as a histogram of conductance occurrence , in such a way that a flat plateau generates a histogram peak.@xcite by linearly adding the histograms associated to each conductance curve , a global histogram is generated , which describes the general tendencies of an ensemble of nw s .
the global histogram displays well defined peaks close to the integer multiples of the conductance quantum ; this fact has been adopted as a proof of the tendency to conductance quantization in metal nws.@xcite the statistical method , discussed above , provides information on the average behavior but it hinders the study of nw transport properties ..
Please generate the next two sentences of the article | for example , it is not possible to get the detailed information on how structural factors influence the conductance evolution . for several years
, the structure evolution was derived from molecular dynamics simulations , where the high computer cost imposes the use of simplified potentials based on effective medium theory ; @xcite subsequently free electron methods were applied to estimate the conduction of the metallic neck ( or confining potential ) . |
3,004 | Suppose that you have an abstract for a scientific paper: we report simultaneous h110@xmath0 and h@xmath1co line observations with the nrao green bank telescope toward 72 h ii regions in the spitzer / glimpse survey area ( @xmath2l@xmath2 = 10@xmath3 @xmath4 65@xmath3 and @xmath2b@xmath2 @xmath5 1@xmath3 ) .
we used the h110@xmath0 line to establish the velocity of the h ii regions and h@xmath1co absorption lines to distinguish between near and far distances .
accurate distances are crucial for the determination of physical properties of massive star formation regions .
we resolved the distance ambiguity of 44 h ii regions .
we detected multiple h ii regions along 18 lines of sight located in the longitude interval 12@xmath3 to 31@xmath3 , primarily a result of the relatively large telescope beam width .
we could not resolve distance ambiguities for lines of sight with multiple h ii regions , since we could not determine which h@xmath1co lines were being absorbed against which h ii region .
we examined the projected location of h ii regions whose distance ambiguities have been resolved ( in this work and other similar studies ) in the galactic plane and in a longitude - velocity diagram for a recognizable spiral arm pattern .
although the highest density of points in the position - position plot approximately follows the spiral arms proposed by taylor and cordes ( 1993 ) , the dispersion is still about as large as the separation between their proposed arms .
the longitude - velocity plot shows an increase in the density of sources at the points where the spiral arm loci proposed by taylor and cordes ( 1993 ) are approaching the locus of tangent point velocities and a lower density between the arm loci .
however , it is not possible to trace spiral arms over significant segments of galactic longitude in the longitude - velocity plot .
we conclude that a very large number of h ii regions in combination with more sophisticated galactic rotation models will be required to obtain a more continuous spiral pattern from kinematic studies of h ii....
And you have already written the first three sentences of the full article: the determination of distances to astronomical objects is perhaps one of the oldest and most important problems in astronomy .
accurate distances are necessary to establish physical properties of sources as well as the distribution of different classes of objects in the galaxy . in particular
, for objects that are believed to be tracers of spiral structure , such as massive star formation regions , one may infer the number and location of spiral arms in the galaxy . for most sources located in the galactic plane ,.
Please generate the next two sentences of the article | optical distance determination methods can not be used due to the large opacity of interstellar dust . the usual way to estimate distances to radio sources ( e.g. , molecular clouds , h ii regions , pns )
is based on the kinematic properties of the galactic plane . |
3,005 | Suppose that you have an abstract for a scientific paper: following the general strategy proposed by g.rybnikov , we present a proof of his well - known result , that is , the existence of two arrangements of lines having the same combinatorial type , but non - isomorphic fundamental groups .
to do so , the alexander invariant and certain invariants of combinatorial line arrangements are presented and developed for combinatorics with only double and triple points .
this is part of a more general project to better understand the relationship between topology and combinatorics of line arrangements .
one of the main subjects in the theory of hyperplane arrangements is the relationship between combinatorics and topological properties . to be precise
, one has to make the following distinction : for a given hyperplane arrangement @xmath0 , one can study the topological type of the pair @xmath1 or the topological type of the complement @xmath2 .
for the first concept we will use the term _ relative topology _ of @xmath3 , whereas for the second one we will simply say _ topology _ of @xmath3 .
it is clear that if two hyperplane arrangements have the same relative topology , then they have the same topology , but the converse is not known . in
a well - known and very cited work @xcite , g. rybnikov found an example of two line arrangements @xmath4 and @xmath5 in the complex projective plane @xmath6 having the same combinatorics but different topology .
the most common way to prove that two topologies of line arrangements are different is to check that the fundamental groups of their complements are not isomorphic .
recently , the authors of this work have provided an example of two line arrangements with different relative topologies ( see @xcite ) .
the contribution of @xcite is that it refers to real arrangements , that is , arrangements that admit real equations for each line ( note that rybnikov s example can not have real equations ) .
the proof proposed by rybnikov has two steps .
let @xmath7 , @xmath8 . 1 . [ r1 ] recall....
And you have already written the first three sentences of the full article: we want to thank g.rybnikov for his contribution and his support .
his work has been a challenge for us for years .
in this section , some standard facts about line combinatorics and ordered line combinatorics will be described ..
Please generate the next two sentences of the article | special attention will be given to maclane and rybnikov s line combinatorics .
a _ combinatorial type _ ( or simply a _ ( line ) combinatorics _ ) is a couple @xmath24 , where @xmath25 is a finite set and @xmath26 , satisfying that : 1 . for all @xmath27 , @xmath28 ; 2 . for any @xmath29 , @xmath30 , @xmath31 such that @xmath32 . |
3,006 | Suppose that you have an abstract for a scientific paper: we have developed a new method to derive the magnetic field distribution on the surfaces of rotating magnetic white dwarfs from phase - resolved flux and circular polarization spectra .
an optimization code based on an evolutionary strategy is used to fit synthetic zeeman spectra for a variety of model geometries described in the framework of a truncated multipole expansion .
we demonstrate that the code allows the reconstruction of relatively complex fields using noise - added synthetic input spectra . as a first application
, we analyze flux and circular polarization spectra of the polar eferi in a low state of accretion taken with fors1 at the eso vlt . .
And you have already written the first three sentences of the full article: we use a pre - computed database of 46800 synthetic flux and polarization spectra for field strengths of 1400 mg and a wide range of effective temperatures to generate synthetic zeeman spectra , which we subject to an automatic optimization scheme with the aim to recover the parameters describing the original magnetic field configuration .
we adopt input field geometries which involve the sum of non - aligned dipole and quadrupole components .
we also provide for off - centre shifts of the configuration . by adding gaussian noise we create input spectra with and 20 , respectively ..
Please generate the next two sentences of the article | = 0.80 off - centred dipole - quadrupole combinations are reliably recovered even for by our code , which can handle up to 12 free parameters but becomes inefficient if higher multipoles are included .
the poor convergence is caused by the complexity of the @xmath0-landscape , which develops an increasing number of secondary minima for more complex field geometries ( for a detailed investigation , see euchner et al . , 2002 ) . |
3,007 | Suppose that you have an abstract for a scientific paper: the relationship between two different asymptotic techniques , namely , the wigner - weyl kinetic formalism and the complex geometrical optics method , is addressed within the framework of semiclassical theory of wave propagation . more specifically , in correspondence to appropriate boundary conditions , the solution of the wave kinetic equation , relevant to the wigner - weyl formalism , is obtained in terms of the corresponding solution of the complex geometrical optics equations . in particular , this implies that the two considered techniques yield the same wavefield intensity . such a result is also discussed on the basis of the analytical solution of the wave kinetic equation specific to gaussian beams of electromagnetic waves propagating in a `` lens - like '' medium for which the complex geometrical optics solution is already available . .
And you have already written the first three sentences of the full article: in the framework of the semiclassical theory of waves [ 1 - 5 ] , i.e. , short wavelength asymptotics , the uniform ( global ) description of the wavefield is complicated by the formation of caustic singularities [ 1 , 2 , 6 - 8 ] .
although a complete and deep understanding of the wavefield structure near caustic regions is obtained on the basis of catastrophe theory @xcite and the unfolding of the corresponding singularities can be treated by means of symplectic techniques @xcite , the application of such methods to realistic cases , e.g. , to waves in magnetically confined plasmas @xcite , appears rather difficult .
therefore , with specific regard to physical applications , several asymptotic methods have been developed which yield numerically tractable equations , though being limited concerning the global properties of the asymptotic solutions ..
Please generate the next two sentences of the article | such asymptotic techniques can be classified into two different families , depending on whether the relevant wave equation is described in the phase space , _ microlocal techniques _ , or directly in the configuration space where the wavefield is defined , _ quasi - optical methods_. this work aims to give a detailed comparative analysis of two such techniques , namely , the wigner - weyl kinetic formalism [ 11 - 13 ] and the complex geometrical optics ( cgo ) method [ 14 - 17 ] which can be considered as benchmarks for microlocal and quasi - optical methods , respectively .
specifically , in sec.2 , the wigner - weyl formalism and the complex geometrical optics method are reviewed and compared . |
3,008 | Suppose that you have an abstract for a scientific paper: we study the second order temporal coherence of the emission from a semiconductor microcavity in the strong coupling regime .
we evidence the favorable influence of spatial confinement , realized by etching micropillar structures , on the temporal coherence of solid state quasi - condensates which evolve in our device above threshold . by fitting the experimental data with a microscopic quantum theory based on a monte carlo wavefunction approach , we scrutinize the influence of the crystal lattice temperature ( interaction with acoustic phonons ) and pump power on the condensate s temporal coherence .
phonon - mediated transitions in the optical mode structure are observed , which in the case of a cofined structure splits into a set of discrete resonances . by increasing the pump power beyond the condensation threshold ,
the temporal coherence significantly improves in the pillar devices , as revealed in the transition from thermal to coherent statistics of the emitted light .
10 s. strauf and f. jahnke , `` single quantum dot nanolaser , '' laser & photonics reviews * 5 * , 607633 ( 2011 ) .
a. imamoglu , r. j. ram , s. pau , and y. yamamoto , `` nonequilibrium condensates and lasers without inversion : exciton - polariton lasers , '' phys .
rev .
a * 53 * , 42504253 ( 1996 ) . c. weisbuch , m. nishioka , a. ishikawa , and y. arakawa , `` observation of the coupled exciton - photon mode splitting in a semiconductor quantum microcavity , '' phys .
rev .
lett . * 69 * , 33143317 ( 1992 ) .
a. v. kavokin , j. j. baumberg , g. malpuech , and f. p. laussy , _ microcavities _ ( oxford university press , 2006 ) .
a. p. d. love , d. n. krizhanovskii , d. m. whittaker , r. bouchekioua , d. sanvitto , s. a. rizeiqi , r. bradley , m. s. skolnick , p. r. eastham , r. andreacute , and l. s. dang , `` intrinsic decoherence mechanisms in the microcavity polariton condensate , '' phys .
rev .
lett .
* 101 * , 067404 ( 2008 ) .
b. deveaud - pldran....
And you have already written the first three sentences of the full article: the temporal coherence of a source of radiation is a key quantity which discriminates a laser - like device from thermal emitters .
while the first order coherence function , @xmath0 , which is the correlator of field amplitudes at different times , reflects the coherence of the emitted photons , its second order counterpart @xmath1 , that involves intensity correlation , gives insights into the emission statistics .
in conventional semiconductor lasers which rely on stimulated emission and population inversion , the emission statistics transits from thermal below lasing threshold to coherent as revealed by @xmath2 and 1 respectively . even in the limiting case of a vanishing threshold occurring in devices where spontaneous emission is perfectly funneled into the lasing mode , laser oscillation.
Please generate the next two sentences of the article | can still be identified since @xmath3 approaches a value of 1 with increasing pump power @xcite .
an example of a light emitting device which may operate as a coherent light source without population inversion , is a semiconductor microcavity in the strong light |
3,009 | Suppose that you have an abstract for a scientific paper: we present high resolution , long slit spectroscopic observations of five compact ( @xmath0 10 arcsec ) planetary nebulae located close to the galactic bulge region and for which no high spatial resolution images are available .
the data have been drawn from the san pedro mrtir kinematic catalogue of galactic planetary nebulae ( lpez et al .
2012 ) .
the central star in four of these objects ( m 132 , m 220 , m 231 and m 315 ) is of wr type and the fifth object ( m 242 ) has a wels type nucleus .
these observations reveal the presence in all of them of a dense and thick equatorial torus - like component and high speed , collimated , bipolar outflows .
the code shape is used to investigate the main morpho
kinematic characteristics and reproduce the 3d structure of these objects assuming a cylindrical velocity field for the bipolar outflows and a homologous expansion law for the torus / ring component .
the deprojected expansion velocities of the bipolar outflows are found to be in the range of 65 to 200 km @xmath1 , whereas the torus / ring component shows much slower expansion velocities , in the range of 15 to 25 km @xmath1 .
it is found that these planetary nebulae have very similar structural components and the differences in their emission line spectra derive mostly from their different projections on the sky .
the relation of their morpho
kinematic characteristics with the wr type nuclei deserves further investigation . [ firstpage ] ism : jets and outflows , ism : kinematics and dynamics , planetary nebula : individual ( m 132 , m 220 , m 231 , m 242 , m 315 ) .
And you have already written the first three sentences of the full article: low to intermediate mass stars ( 0.8 to 8 @xmath2 ) undergo spectacular structural changes during the last phases of their evolution .
according to the interacting stellar wind model ( isw ; kwok purton and fitzgerald 1978 ) , the spherically symmetric pne are formed by the interaction of two isotropic stellar winds , a slow and dense one from the asymptotic giant branch ( agb ) phase and a fast and tenuous one during the pn phase .
the generalized isw model considers in addition the contribution of an equatorial density enhancement at the exit of the agb phase that produces a density contrast leading to the formation of axisymmetric shapes ( e.g. balick 1987 ) that may range from mildly elliptical to bipolar ..
Please generate the next two sentences of the article | in fact , the majority of planetary nebulae ( pne ) and proto pne ( ppne ) show axisymmetric morphologies . in some cases highly collimated ,
high speed bipolar outflows are also found . |
3,010 | Suppose that you have an abstract for a scientific paper: the mathematical properties of a nonlinear parabolic equation arising in the modelling of non - newtonian flows are investigated .
the peculiarity of this equation is that it may degenerate into a hyperbolic equation ( in fact a linear advection equation ) .
depending on the initial data , at least two situations can be encountered : the equation may have a unique solution in a convenient class , or it may have infinitely many solutions .
[ section ] [ section ] [ section ] [ section ] [ section ] [ section ] [ section ] .
And you have already written the first three sentences of the full article: modelling the flow of complex fluids is a very intricate problem which is far from being solved up to now . besides studies which aim at improving phenomenological rheological models ( purely macroscopic constitutive laws )
, only a few attempts are made to recover the rheological behavior of a complex fluid from elementary physical processes arising in its microstructure . + the mesoscopic model which has been proposed by hbraud and lequeux in @xcite deals with simple shear flows of concentrated suspensions .
it is obtained by dividing the material in a large number of mesoscopic elements ( `` blocks '' ) with a given shear stress @xmath0 ( @xmath0 is a real number ; it is in fact an extra - diagonal term of the stress tensor in convenient coordinates ) and by considering the evolution of the probability density @xmath1 which represents the distribution of stress in the assembly of blocks . under various assumptions on the evolution of the stresses of the blocks which will be described below.
Please generate the next two sentences of the article | , the equation for the probability density @xmath1 for a block to be under stress @xmath0 at time @xmath2 may be written as : [ eq : syst - p ] _ tp =- b(t ) _
p+d(p(t ) ) ^2_p - p+_0 ( ) ( 0;t);[eq : p ] + p0 ; + p(0,)=p_0 ( ) , [ eq : p0er ] where for @xmath3 , we denote by @xmath4 in equation ( [ eq : p ] ) , @xmath5}$ ] denotes the characteristic function of the open set @xmath6 $ ] and @xmath7 the dirac delta function on @xmath8 . |
3,011 | Suppose that you have an abstract for a scientific paper: consider the following unequal error protection scenario .
one special message , dubbed the `` red alert '' message , is required to have an extremely small probability of missed detection .
the remainder of the messages must keep their average probability of error and probability of false alarm below a certain threshold .
the goal then is to design a codebook that maximizes the error exponent of the red alert message while ensuring that the average probability of error and probability of false alarm go to zero as the blocklength goes to infinity .
this red alert exponent has previously been characterized for discrete memoryless channels .
this paper completely characterizes the optimal red alert exponent for additive white gaussian noise channels with block power constraints . .
And you have already written the first three sentences of the full article: communication networks are increasingly being taxed by the enormous demand for instantly available , streaming multimedia .
ideally , we would like to maximize the reliability and data rate of a system while simultaneously minimizing the delay . yet , in the classical fixed blocklength setting , the reliability function of a code goes to zero as the rate approaches capacity even in the presence of feedback .
this seems to imply that , close to capacity , it is impossible to keep delay low and reliability high ..
Please generate the next two sentences of the article | however , this lesson is partially an artifact of the block coding framework .
the achievable tradeoff changes in a streaming setting where all bits do not need to be decoded by a fixed deadline , but rather , each individual bit must be recovered after a certain delay . in this |
3,012 | Suppose that you have an abstract for a scientific paper: we study the low - temperature thermal conductivity ( @xmath0 ) of dy@xmath1ti@xmath1o@xmath2 and yb@xmath1ti@xmath1o@xmath2 single crystals in magnetic fields up to 14 t along the [ 111 ] , [ 100 ] and [ 110 ] directions .
the main experimental findings for dy@xmath1ti@xmath1o@xmath2 are : ( i ) the low-@xmath3 @xmath4 isotherms exhibit not only the step - like decreases at the low - field ( @xmath5 2 t ) magnetic transitions but also obvious field dependencies in high fields ( @xmath6 7 t ) ; ( ii ) at @xmath7 0.5 k , the @xmath4 curves show anisotropic irreversibility in low fields , that is , the @xmath4 hysteresis locates at the first - order transition with @xmath8 [ 100 ] and [ 110 ] , while it locates between two successive transitions with @xmath8 [ 111 ] ; ( iii ) the @xmath0 in the hysteresis loops for @xmath8 [ 100 ] and [ 110 ] show an extremely slow relaxation with the time constant of @xmath9 1000 min .
the main experimental findings for yb@xmath1ti@xmath1o@xmath2 are : ( i ) the zero - field @xmath10 show a kink - like decrease at the first - order transition ( @xmath9 200 mk ) with decreasing temperature ; ( ii ) the low-@xmath3 @xmath4 isotherms show a decrease in low field and a large enhancement in high fields ; ( iii ) the low-@xmath3 @xmath4 curves show a sharp minimum at 0.5 t for @xmath8 [ 110 ] and [ 111 ] .
the roles of monopole excitations , field - induced transitions , spin fluctuations and magnetoelastic coupling are discussed . .
And you have already written the first three sentences of the full article: rare - earth titanates @xmath11ti@xmath1o@xmath2 ( @xmath12 rare earth ) have attracted extensive research interests due to their exotic magnetism.@xcite these materials have a pyrochlore crystal structure with the space group @xmath13 , in which the magnetic rare - earth ions form a network of corner - sharing tetrahedra and are prone to a high degree of geometric frustration
. however , these materials are greatly sensitive to weak perturbations ( e.g. single - ion anisotropy , dipolar interaction or quantum fluctuations ) beyond the nearest - neighboring exchange , which results in unconventional low - temperature magnetic and thermodynamic properties .
one famous phenomenon is the classical spin - ice state in ho@xmath1ti@xmath1o@xmath2 and dy@xmath1ti@xmath1o@xmath2 ( with effective ferromagnetic exchange and ising anisotropy).@xcite at low temperatures , their moments have an ising anisotropy due to the strong crystal field with the local easy axis along the [ 111 ] axis ..
Please generate the next two sentences of the article | the ground states have a macroscopically degenerate `` 2-in , 2-out '' spin configuration in each tetrahedron . an interesting finding in the spin - ice materials
is that the magnetic excitations could be emergent magnetic monopoles.@xcite once the flipping of a spin occurs , a local `` 3-in , 1-out '' or `` 3-out , 1-in '' spin configuration forms , which is equivalent to yielding two opposite magnetic monopoles in the adjacent tetrahedra.@xcite for dy@xmath1ti@xmath1o@xmath2 , the external magnetic field along different directions can easily break the degenerate spin - ice state and induce various magnetic states.@xcite for example , with increasing magnetic field along the [ 100 ] axis , the system enters a q = 0 state at @xmath14 0.5 t.@xcite this state has a single spin configuration chosen from the degenerate spin - ice ground state , with all the spins on each tetrahedron having a component along the field direction and actually forming a long - range order . |
3,013 | Suppose that you have an abstract for a scientific paper: conceptual design studies are underway for muon colliders and other high - current muon storage rings that have the potential to become the first true `` neutrino factories '' .
muon decays in long straight sections of the storage rings would produce precisely characterized beams of electron and muon type neutrinos of unprecedented intensity .
this article reviews prospects the for these facilities to greatly extend our capabilities for neutrino experiments , largely emphasizing the physics of neutrino interactions .
muon colliders , muon storage rings , neutrino factories ; * pacs13.15.+g * .
And you have already written the first three sentences of the full article: muon colliders _ _ have been proposed to provide lepton - lepton collisions while circumventing the energy limitations on electron - positron storage rings caused by synchrotron radiation .
the larger muon mass suppresses synchrotron radiation energy losses by a factor @xmath0 relative to those of a circulating electron beam of the same energy and , incidentally , also opens up promising possibilities for @xmath1channel higgs boson production@xcite .
recent feasibility and design studies for future muon colliders @xcite have begun to focus attention on the exciting physics possibilities for experiments using neutrino beams from the decays of the circulating high energy muons ..
Please generate the next two sentences of the article | this report explores the potential for a `` neutrino experiment at a muon collider '' , or @xmath2mc for short .
a @xmath2mc program could operate either parasitically during a colliding beam experiment ; or it could be installed as part of a program in neutrino physics at a dedicated muon storage ring . amongst the potential physics topics for @xmath2mcs , neutrino oscillations have garnered the most intense experimental and theoretical activity , and particular possibilities for long baseline oscillation experiments exploiting a muon storage ring are covered elsewhere@xcite . in this report , we wish to also highlight the superb capabilities of neutrinos as probes of the strong and weak interaction dynamics of quarks and the parton structure of nucleons , as well as the power of a @xmath2mc in searches for evidence of new types of weak interactions . |
3,014 | Suppose that you have an abstract for a scientific paper: we demonstrate that in - bulk vortex localized modes , and their surface half - vortex ( horseshoe " ) counterparts self - trap in two - dimensional ( 2d ) nonlinear optical systems with @xmath0-symmetric photonic lattices ( pls ) .
the respective stability regions are identified in the underlying parameter space .
the in - bulk states are related to truncated nonlinear bloch waves in gaps of the pl - induced spectrum .
the basic vortex and horseshoe modes are built , severally , of four and three beams with appropriate phase shifts between them .
their stable complex counterparts , built of up to 12 beams , are reported too .
nonlinear spatially periodic systems support diverse types of self - trapped in - gap states .
in particular , spatial gap solitons @xcite originate from the interplay between the periodicity and nonlinearity .
further , surface gap solitons @xcite appear at the interface between a uniform medium and a photonic lattice ( pl ) built into a nonlinear material .
extended self - trapped waves with steep edges also exist in these settings , being related to truncated nonlinear bloch waves @xcite .
modes of the latter type provide a link between extended nonlinear bloch waves @xcite and tightly localized gap solitons @xcite .
recently , a great deal of interest has been drawn to the realization of parity - time ( @xmath0 ) symmetry in optics .
originally , this concept was developed in quantum mechanics , where it was demonstrated that , beyond the conventional hermitian hamiltonians , their @xmath0-symmetric non - hermitian counterparts may also give rise to purely real ( hence physically relevant ) spectra @xcite .
following the similarity between quantum mechanics and paraxial optics @xcite , @xmath0-symmetric optical systems with complex refractive indices @xcite have been extensively studied theoretically @xcite and experimentally @xcite . in this context ,
@xmath0-symmetric pls play an important role .
taking into account the non -....
And you have already written the first three sentences of the full article: this work was supported by the national basic research program of china under grants nos .
2012cb821305 , 2010cb923200 and 2013cb922403 , the national natural science foundation of china under grants nos . 11374375 , 11204043 , 11274399 and 61078027 , and the ph.d .
programs foundation of ministry of education of china under grant nos ..
Please generate the next two sentences of the article | b.a.m . appreciates hospitality of the sun yat - sen university ( guangzhou , china ) . |
3,015 | Suppose that you have an abstract for a scientific paper: we present the first proper motion study of m10 ( ngc 6254 ) .
absolute proper motions of about 532 stars in the field of the globular cluster m10 were determined with respect to hipparcos and act reference stars .
in addition to photographic plates of bonn and shanghai also wide field ccd observations as second epoch plates were used .
the wide field ccd observations show an accuracy comparable to that of the photographic plates . a good coincidence of the solutions based on reference stars from hipparcos and from act was found .
our final proper motions allow a sufficient separation of cluster and field stars .
two population ii cepheids were confirmed to be members of m10 .
the absolute proper motion of m10 was determined and combined with its distance from the sun and its radial velocity .
the space motion and metallicity of m10 indicates the characteristics of a halo object with an orbit reaching to a maximal @xmath0-distance of less than 3 kpc . .
And you have already written the first three sentences of the full article: globular clusters are important tracers of the chemical and dynamical evolution of the milky way .
since the orbits of globular clusters may have kept their characteristics from the early times of the formation of the milky way , we may extract from their kinematics some clues for the understanding of the origin of the milky way .
however so far for only some 40 globular clusters absolute proper motions exist ( dinescu et al ..
Please generate the next two sentences of the article | 1999 ) , which partly are of low quality ( e.g. dauphole et al . 1996 ) . nevertheless on the basis of a sample of 26 globular clusters
dauphole et al . |
3,016 | Suppose that you have an abstract for a scientific paper: we present x - ray spectral analysis of five _ chandra _ and _ xmm - newton_observations of the gravitationally - lensed blazar pks 1830@xmath0211 from 2000 to 2004 .
we show that the x - ray absorption toward pks 1830@xmath0211 is variable , and the variable absorption is most likely to be intrinsic with amplitudes of @xmath1@xmath2 depending on whether or not the absorber is partially covering the x - ray source .
our results confirm the variable absorption observed previously , although interpreted differently , in a sequence of _ asca _ observations .
this large variation in the absorption column density can be interpreted as outflows from the central engine in the polar direction , consistent with recent numerical models of inflow / outflows in agns .
in addition , it could possibly be caused by the interaction between the blazar jet and its environment , or the variation from the geometric configuration of the jet . while the spectra can also be fitted with a variable absorption at the lens redshift
, we show that this model is unlikely .
we also rule out the simple microlensing interpretation of variability which was previously suggested . .
And you have already written the first three sentences of the full article: pks 1830@xmath0211 @xcite consists of two @xmath3 @xcite blazar images separated by 1 and lensed by a @xmath4 @xcite spiral galaxy @xcite . pks 1830@xmath0211 was observed in the radio ( e.g. , * ? ? ?
* ; * ? ? ?
* ) , infrared ( e.g. , * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
* ; * ? ? ? |
3,017 | Suppose that you have an abstract for a scientific paper: measurements of maximum magnetic flux , minimum intensity , and size are presented for 12967 sunspot umbrae detected on the nasa / nso spectromagnetograms between 1993 and 2004 to study umbral structure and strength during the solar cycle .
the umbrae are selected using an automated thresholding technique
. measured umbral intensities are first corrected for a confirming observation of umbral limb - darkening . log
normal fits to the observed size distribution confirm that the size spectrum shape does not vary with time . the intensity magnetic flux relationship is found to be steady over the solar cycle . the dependence of umbral size on the magnetic flux and minimum intensity are also independent of cycle phase and give linear and quadratic relations , respectively .
while the large sample size does show a low amplitude oscillation in the mean minimum intensity and maximum magnetic flux correlated with the solar cycle , this can be explained in terms of variations in the mean umbral size .
these size variations , however , are small and do not substantiate a meaningful change in the size spectrum of the umbrae generated by the sun . thus ,
in contrast to previous reports , the observations suggest the equilibrium structure , as testified by the invariant size - magnetic field relationship , as well as the mean size ( _ i.e. _ strength ) of sunspot umbrae do not significantly depend on solar cycle phase . .
And you have already written the first three sentences of the full article: magnetohydrostatic equilibrium describes the balance of the magnetic and thermal pressures across individual sunspots @xcite . along the direction parallel to the solar surface , the local environment of a sunspot markedly shifts from the cooler , convection inhibited , umbral region , hosting multi - kilogauss magnetic fields , to the convectively turbulent , hotter , external plasma of the quiet sun with considerably lower magnetic flux density .
the mechanism responsible for this inverse relationship between magnetic field strength and temperature remains unclear @xcite since umbrae host a wide range of thermal - magnetic field distributions @xcite .
interesting , however , is the empirical relationship between peak magnetic field strength and minimum intensity for different umbrae @xcite . support a single power law to express this relationship . as such.
Please generate the next two sentences of the article | , the total magnetic pressure of a sunspot always _ more than _ compensates for the corresponding reduction in thermal pressure , leading to a predictably larger spatial extent for umbrae with greater field strengths @xcite and lower minimum intensities @xcite .
however , to date , no study of the temporal stability of the relationship claimed by norton and gilman has been completed for a statistically significant number of umbrae . |
3,018 | Suppose that you have an abstract for a scientific paper: we consider two - mode squeezed states which are parametrized by the squeezing parameter and the phase .
we present a scheme for teleporting such entangled states of continuous variables from alice to bob .
our protocol is operationalized through the creation of a four - mode entangled state shared by alice and bob using linear amplifiers and beam splitters .
teleportation of the entangled state proceeds with local operations and the classical communication of four bits .
we compute the fidelity of teleportation and find that it exhibits a trade - off with the magnitude of entanglement of the resultant teleported state . 0.5 cm .
And you have already written the first three sentences of the full article: quantum teleportation is an important and vital quantum information processing task where an arbitrary unknown quantum state can be replicated at a distant location using previously shared entanglement and classical communication between the sender and the receiver .
a remarkable application of entangled states having many ramifications in information technology , quantum teleportation can also be combined with other operations to construct advanced quantum circuits useful for information processing@xcite .
the original teleportation protocol of bennett et al.@xcite for an unknown qubit using an epr pair has been generalized to the case of non - maximally entangled or a noisy channel between the sender and the receiver@xcite ..
Please generate the next two sentences of the article | the loss of fidelity for teleportation using non - maximally entangled channels could be compensated by schemes for probabilistic teleportation@xcite .
the first experimental demonstration of quantum teleportation was reported by bouwmeester et al.@xcite . |
3,019 | Suppose that you have an abstract for a scientific paper: in this paper we are considering a semilinear singular perturbation reaction diffusion boundary value problem , which contains a small perturbation parameter that acts on the highest order derivative .
we construct a difference scheme on an arbitrary nonequidistant mesh using a collocation method and green s function .
we show that the constructed difference scheme has a unique solution and that the scheme is stable .
the central result of the paper is @xmath0-uniform convergence of almost second order for the discrete approximate solution on a modified shishkin mesh .
we finally provide two numerical examples which illustrate the theoretical results on the uniform accuracy of the discrete problem , as well as the robustness of the method .
example.eps gsave newpath 20 20 moveto 20 220 lineto 220 220 lineto 220 20 lineto closepath 2 setlinewidth gsave .4 setgray fill grestore stroke grestore .
And you have already written the first three sentences of the full article: we consider the semilinear singularly perturbed problem @xmath1 , \label{uvod1 } \\
y(0)&=0,\ y(1)=0 , \label{uvod2}\end{aligned}\ ] ] where @xmath2 we assume that the nonlinear function @xmath3 is continuously differentiable , i.e. that @xmath4\times \mathbb{r}\right)$ ] , for @xmath5 and that @xmath3 has a strictly positive derivative with respect to @xmath6 @xmath7\times \mathbb{r}\:\ : \quad ( m = const ) .
\label{uvod3}\ ] ] the solution @xmath6 of the problem exhibits sharp boundary layers at the endpoints of @xmath8 $ ] of @xmath9 @xmath10 width ..
Please generate the next two sentences of the article | it is well known that the standard discretization methods for solving are unstable and do not give accurate results when the perturbation parameter @xmath0 is smaller than some critical value . with this in mind , we therefore need to develop a method which produces a numerical solution for the starting problem with a satisfactory value of the error .
moreover , we additionally require that the error does not depend on @xmath0 ; in this case we say that the method is uniformly convergent with respect to @xmath0 or @xmath0-uniformly convergent . |
3,020 | Suppose that you have an abstract for a scientific paper: we present a method for explicit leapfrog integration of inseparable hamiltonian systems by means of an extended phase space . a suitably defined new hamiltonian on the extended phase space leads to equations of motion that can be numerically integrated by standard symplectic leapfrog ( splitting ) methods .
when the leapfrog is combined with coordinate mixing transformations , the resulting algorithm shows good long term stability and error behaviour .
we extend the method to non - hamiltonian problems as well , and investigate optimal methods of projecting the extended phase space back to original dimension .
finally , we apply the methods to a hamiltonian problem of geodesics in a curved space , and a non - hamiltonian problem of a forced non - linear oscillator .
we compare the performance of the methods to a general purpose differential equation solver lsode , and the implicit midpoint method , a symplectic one - step method .
we find the extended phase space methods to compare favorably to both for the hamiltonian problem , and to the implicit midpoint method in the case of the non - linear oscillator . .
And you have already written the first three sentences of the full article: second order leapfrog or splitting methods are a class of widely used time - symmetric , explicit and symplectic integration algorithms for hamiltonian systems .
these characteristics make them a standard tool for very long integrations , as they preserve the phase space structure and first integrals of the system .
being time - symmetric , second order leapfrog algorithms have an error expansion that only contains even powers of the timestep ..
Please generate the next two sentences of the article | this fact makes them convenient for use within extrapolation schemes , such as the gragg bulirsch
stoer ( gbs ) method @xcite , which are often used when very high accuracy is required @xcite . |
3,021 | Suppose that you have an abstract for a scientific paper: while the quantum hall effect in graphene has been regarded as a realization of the _ anomaly _ associated with the massless dirac particle carrying half the usual topological integer , this is hidden due to the doubling of the dirac cones . in order to confirm the half - integer contribution from each dirac cone , here we theoretically consider a lattice model in which the relative energy between the two dirac points is systematically shifted . with an explicit calculation of the topological ( chern ) number
, we have demonstrated that each dirac cone does indeed contribute to the hall conductivity as the half odd integer series ( @xmath0 ) when the fermi energy traverses the ( shifted sets of ) landau levels .
the picture is also endorsed , via the bulk - edge correspondence , from the edge mode spectrum for the present model . .
And you have already written the first three sentences of the full article: in the seminal discovery of the quantum hall effect ( qhe ) in graphene@xcite , a most striking point is that the graphene qhe is regarded as a realization of the _ anomaly_@xcite in the massless dirac particle , where each dirac cone carries 1/2 of the usual qhe topological number@xcite .
namely , in place of the usual hall conductivity , @xmath1 ( in units of @xmath2 , with the spin degrees of freedom dropped here ) , we have @xmath3 .
the standard understanding is that the honeycomb lattice has a couple of dirac cones at k and k points in the brillouin zone , so that we just divide the above formula by 2 to have @xmath4 for the contribution from each valley ..
Please generate the next two sentences of the article | the half integers are thus hidden in the total hall conductivity .
since the nielsen - ninomiya theorem@xcite dictates that dirac cones should always appear in pairs as far as the chiral symmetry is present , we can pose an important question : is it really impossible to resolve the half - integer components ? in terms of field theory |
3,022 | Suppose that you have an abstract for a scientific paper: the consecutive - ones property ( c1p ) is a classical concept in discrete mathematics that has been used in several genomics applications , from physical mapping of contemporary genomes to the assembly of ancient genomes . a common issue in genome assembly concerns repeats , genomic sequences that appear in several locations of a genome .
handling repeats leads to a variant of the c1p , the c1p with multiplicity ( mc1p ) , that can also be seen as the problem of covering edges of hypergraphs by linear and circular walks . in the present work ,
we describe variants of the mc1p that address specific issues of genome assembly , and polynomial time or fixed - parameter algorithms to solve them . .
And you have already written the first three sentences of the full article: a binary matrix @xmath0 satisfies the consecutive - ones property ( c1p ) if its columns can be ordered in such a way that , in each row , all 1 entries appear consecutively .
the c1p has been studied in relation to a wide range of problems , from theoretical computer science @xcite to genome mapping ( see @xcite and references there ) .
the c1p can be naturally described in terms of covering hypergraph edges by walks ..
Please generate the next two sentences of the article | assume a binary matrix @xmath0 is the incidence matrix of a hypergraph @xmath1 , where columns represent vertices and rows encode edges ; then @xmath0 is c1p if and only if @xmath1 can be covered by a path that contains all vertices and where every edge appears as a contiguous subpath .
deciding if a binary matrix is c1p can be done in linear time and space ( see @xcite and references there ) . |
3,023 | Suppose that you have an abstract for a scientific paper: we study quench dynamics of the bose - hubbard model by exact diagonalization .
initially the system is at thermal equilibrium and of a finite temperature .
the system is then quenched by changing the on - site interaction strength @xmath0 suddenly . both the single - quench and double - quench scenarios are considered . in the former case ,
the time - averaged density matrix and the real - time evolution are investigated .
it is found that though the system thermalizes only in a very narrow range of the quenched value of @xmath0 , it does equilibrate or relax well in a much larger range .
most importantly , it is proven that this is guaranteed for some typical observables in the thermodynamic limit . in order to test whether it is possible to distinguish the unitarily evolving density matrix from the time - averaged ( thus time - independent ) , fully decoherenced density matrix ,
a second quench is considered .
it turns out that the answer is affirmative or negative according to the intermediate value of @xmath0 is zero or not . .
And you have already written the first three sentences of the full article: out - of - equilibrium dynamics following a quantum quench is a topic of intense study at present .
the theme is pursued primarily along two lines .
the first one is about the equilibration and thermalization mechanism of a quantum system @xcite , a fundamental yet still open issue in statistical physics ..
Please generate the next two sentences of the article | the second one is about the the real - time dynamical behavior of a many - body system @xcite , which is highly non - trivial in the regime where the quasi - particle picture breaks down . among all the models investigated so far
, the bose - hubbard model takes a special position . as a paradigmatic strongly - correlated model , |
3,024 | Suppose that you have an abstract for a scientific paper: a notion of quantum conference is introduced in analogy with the usual notion of a conference that happens frequently in today s world .
quantum conference is defined as a multiparty secure communication task that allows each party to communicate their messages simultaneously to all other parties in a secure manner using quantum resources .
two efficient and secure protocols for quantum conference have been proposed .
the security and efficiency of the proposed protocols have been analyzed critically .
it is shown that the proposed protocols can be realized using a large number of entangled states and group of operators .
further , it is shown that the proposed schemes can be easily reduced to protocol for multiparty quantum key distribution and some earlier proposed schemes of quantum conference , where the notion of quantum conference was different .
keywords : quantum conference , quantum cryptography , secure quantum communication , multiparty quantum communication . .
And you have already written the first three sentences of the full article: in 1984 , an unconditionally secure key distribution protocol using quantum resources was proposed by bennett and brassard @xcite .
the scheme , which is now known as bb84 protocol drew considerable attention of the cryptography community by its own merit as it offered unconditional security , which was unachievable by any classical protocol of key distribution .
however , the relevance of bb84 quantum key distribution ( qkd ) protocol and a set of other schemes of qkd were actually established very strongly in 1994 , when the seminal work of shor @xcite established that rsa @xcite and a few other schemes of classical cryptography @xcite would not remain secure if a scalable quantum computer is built ..
Please generate the next two sentences of the article | the bb84 protocol , not only established the possibility of obtaining unconditional security , but also manifested enormous power of quantum resources that had been maneuvered since then .
specifically , this attempt at the unconditional security of qkd was followed by a set of protocols for the same task @xcite . |
3,025 | Suppose that you have an abstract for a scientific paper: in some special zones of the high - dimensional coordinate space of few - body systems with identical particles , the operation of an element ( or a product of elements ) of the symmetry groups of the hamiltonian on a quantum state might be equivalent to the operation of another element . making use of the matrix representations of the groups
, the equivalence leads to a set of homogeneous linear equations imposing on the wave functions . when the matrix of these equations is non - degenerate
, the wave functions will appear as nodal surfaces in these zones . in this case , these zones are prohibited . in this paper , tightly bound 4-boson systems with three types of interaction have been studied analytically and numerically .
the existence of the universal prohibited zones has been revealed , and their decisive effect on the structures of the eigenstates is demonstrated . .
And you have already written the first three sentences of the full article: since various systems may be governed by the same fundamental law , universality exists in nature .
the early indications of universality in quantum mechanic three - body systems was discovered before 1970.@xcite the first strong evidence was given by efimov in 1970 on three weakly bound identical bosons.@xcite he found that , when the scattering length is sufficiently long , a sequence of loosely bound states , the `` efimov states '' , will appear .
the properties of these states are governed by a universal law , not depend on the dynamic details of the 3-boson systems . in this paper ,.
Please generate the next two sentences of the article | another kind of universality that exists in tightly bound quantum mechanic few - body systems is revealed and confirmed numerically .
the hamiltonian of identical particles is invariant under the operations of a set of symmetry groups @xmath0 , @xmath1 , @xmath2 ( including the permutation group).@xcite consequently , the eigenstates @xmath3 are classified according to the representations of these groups , where @xmath4 denotes a set of coordinates and @xmath5 is a serial number . |
3,026 | Suppose that you have an abstract for a scientific paper: in a previous work one of the authors proposed a simple model for studying systems under pressure based on the thomas - fermi ( tf ) model of single atom . in this work
we intend to extend the previous work to more general thomas - fermi models where electronic exchange and correlation are introduced .
to do so , we first study numerically the equation obtained by h.w.lewis ( tfdl ) which introduces the effects of exchange and correlation into the original tf equation ; next the procedure followed in the previous work is extended to the new approach and a specific example is illustrated .
although one could expect that no big differences were produced by the generalized tf model , we show the qualitative as well as quantitative equivalence with detailed numerical results .
these results support the robustness of our conclusions with regards to the model proposed in the previous work and give the character of universality ( i.e. to pass from one atom to another , the quantities calculated must be simply scaled by a numerical factor ) to the properties of compressed systems shown in this work . .
And you have already written the first three sentences of the full article: the statistical model of atom developed by e.fermi @xcite and known as thomas - fermi model , although based on a highly simplified theoretical framework , has been proven surprisingly good in predicting basic properties of condensed matter @xcite .
a particular feature of such a model is the description of compressed atoms , in this case the predicted properties were confirmed experimentally @xcite . in a preceding publication @xcite , we focused the attention on this particular aspect of the theory and proposed a simple model for describing systems under pressure .
the central point of that work was the development of the concept of `` statistical ionization '' ..
Please generate the next two sentences of the article | in simple terms , this is a universal semianalytical function which enables one to describe , as a function of the distance from the point - like nucleus , the balancing process between the antibinding and binding contribution to the total energy within the compressed atom . in spite of the approximations done and extensively discussed
, we underlined the utility of the proposed model as a tool for investigating at a basic level and at low computational cost , properties of systems under pressure . |
3,027 | Suppose that you have an abstract for a scientific paper: the phenomena of stochasticity in biochemical processes have been intriguing life scientists for the past few decades .
we now know that living cells take advantage of stochasticity in some cases and counteract stochastic effects in others .
the source of intrinsic stochasticity in biomolecular systems are random timings of individual reactions , which cumulatively drive the variability in outputs of such systems . despite the acknowledged relevance of stochasticity in the functioning of living cells no rigorous method
have been proposed to precisely identify sources of variability . in this paper
we propose a novel methodology that allows us to calculate contributions of individual reactions into the variability of a system s output .
we demonstrate that some reactions have dramatically different effects on noise than others .
surprisingly , in the class of open conversion systems that serve as an approximate model of signal transduction , the degradation of an output contributes half of the total noise .
we also demonstrate the importance of degradation in other relevant systems and propose a degradation feedback control mechanism that has the capability of an effective noise suppression .
application of our method to some well studied biochemical systems such as : gene expression , michaelis - menten enzyme kinetics , and the p53 system indicates that our methodology reveals an unprecedented insight into the origins of variability in biochemical systems . for many systems
an analytical decomposition is not available ; therefore the method has been implemented as a matlab package and is available from the authors upon request .
+ living cells need to constantly adapt to their changing environment .
they achieve this through finely honed decision making and stress response machineries that regulate and orchestrate the physiological adaptation to new conditions . in all studied genomes a large number of proteins have as their primary function the transfer and processing of such....
And you have already written the first three sentences of the full article: we consider a general system of @xmath0 chemical species @xcite inside a fixed volume with @xmath1 denoting the number of molecules .
the stoichiometric matrix @xmath2 describes changes in the population size due to @xmath3 different reaction channels , where each @xmath4 describes the change in the number of molecules of type @xmath5 from @xmath6 to @xmath7 caused by an event of type @xmath8 .
the probability that event @xmath8 occurs during the time interval @xmath9 equals @xmath10 , where the @xmath11 are called the transition rates ..
Please generate the next two sentences of the article | this specification leads to a poisson birth and death process described by the following stochastic equations @xcite @xmath12 where the @xmath13 are independent poisson processes with rate 1 . in order to define the contribution of the @xmath8th reaction @xmath14 to the variability of @xmath15
we first define @xmath16 as the expectation of @xmath17 conditioned on the processes @xmath18 so that @xmath19 is a random variable where timings of reaction @xmath8 have been averaged over all possible times , keeping all other reactions fixed . |
3,028 | Suppose that you have an abstract for a scientific paper: lecture notes for the summer school `` microswimmers from single particle motion to collective behaviour '' at forschungszentrum jlich , 2015 . .
And you have already written the first three sentences of the full article: if elongated active , _ i.e. _ self - propelled , objects interact by pushing each other in a dissipative medium or substrate , the objects will tend to locally align @xcite as shown in fig .
[ fig - model ] .
since these object are self - propelled , once aligned , they will move together in the same direction for a given time ..
Please generate the next two sentences of the article | this simple effective alignment mechanism among active objects lead to interesting collective effects @xcite , as the formation of moving cluster as illustrated in fig .
[ fig : myxo ] with experiments of myxobacteria . |
3,029 | Suppose that you have an abstract for a scientific paper: magnetic properties of a charged spin-1 bose gas with ferromagnetic interactions is investigated within mean - field theory .
it is shown that a competition between paramagnetism , diamagnetism and ferromagnetism exists in this system .
it is shown that diamagnetism , being concerned with spontaneous magnetization , can not exceed ferromagnetism in very weak magnetic field . the critical value of reduced ferromagnetic coupling of paramagnetic phase to ferromagnetic phase transition @xmath0 increases with increasing temperature .
the lande - factor @xmath1 is introduced to describe the strength of paramagnetic effect which comes from the spin degree of freedom .
the magnetization density @xmath2 increases monotonically with @xmath1 for fixed reduced ferromagnetic coupling @xmath3 as @xmath4 . in a weak magnetic field
, ferromagnetism makes immense contribution to the magnetization density . while at a high magnetic field , the diamagnetism inclines to saturate .
evidence for condensation can be seen in the magnetization density at weak magnetic field . .
And you have already written the first three sentences of the full article: the magnetism of fermi gases has always received considerable attention in solid - state physics , such as localized and itinerant electrons . while the magnetic properties of bose gases has been less studied .
but since the realization of bose - einstein condensation ( bec ) in ultracold atomic gases @xcite , more interests have been cast to this system .
the bose gases plays an important role in understanding some exotic quantum phenomena , such as superconductivity and superfluid ..
Please generate the next two sentences of the article | the ideal charged bosons were used originally to describe the superconductivity .
it has been shown by schafroth @xcite , blatt and butler @xcite that an ideal gas of charged bosons exhibits the essential equilibrium features of superconductor . |
3,030 | Suppose that you have an abstract for a scientific paper: modern astrophysics is based on multi - wavelength data organized into large and heterogeneous catalogs .
hence , the need for efficient , reliable and scalable catalog cross - matching methods plays a crucial role in the era of the petabyte scale .
furthermore , multi - band data have often very different angular resolution , requiring the highest generality of cross - matching features , mainly in terms of region shape and resolution . in this work we present @xmath0 ( command - line catalog cross - match ) , a multi - platform application designed to efficiently cross - match massive catalogs .
it is based on a multi - core parallel processing paradigm and conceived to be executed as a stand - alone command - line process or integrated within any generic data reduction / analysis pipeline , providing the maximum flexibility to the end - user , in terms of portability , parameter configuration , catalog formats , angular resolution , region shapes , coordinate units and cross - matching types . using real data , extracted from public surveys ,
we discuss the cross - matching capabilities and computing time efficiency also through a direct comparison with some publicly available tools , chosen among the most used within the community , and representative of different interface paradigms .
we verified that the @xmath0 tool has excellent capabilities to perform an efficient and reliable cross - matching between large data sets .
although the elliptical cross - match and the parametric handling of angular orientation and offset are known concepts in the astrophysical context , their availability in the presented command - line tool makes @xmath0 competitive in the context of public astronomical tools . .
And you have already written the first three sentences of the full article: in the last decade we entered the data - intensive era of astrophysics , where the size of data has rapidly increased , reaching in many cases dimensions overcoming the human possibility to handle them in an efficient and comprehensible way . in a very close future petabytes of data
will be the standard and , to deal with such amount of information , also the data analysis techniques and facilities must quickly evolve .
for example the current exploration of petabyte - scale , multi - disciplinary astronomy and earth observation synergy , by taking the advantage from their similarities in data analytics , has issued the urgency to find and develop common strategies able to achieve solutions in the data mining algorithms , computer technologies , large scale distributed database management systems as well as parallel processing frameworks @xcite ..
Please generate the next two sentences of the article | astrophysics is one of the most involved research fields facing with this data explosion , where the data volumes from the ongoing and next generation multi - band and multi - epoch surveys are expected to be so huge that the ability of the astronomers to analyze , cross - correlate and extract knowledge from such data will represent a challenge for scientists and computer engineers . to quote just a few ,
the esa euclid space mission will acquire and process about 100 gbday@xmath1 over at least 6 years , collecting a minimum amount of about @xmath2 tb of data @xcite ; pan - starrs @xcite is expected to produce more than @xmath3 tb of data ; the gaia space mission will build a @xmath4 map of the milky way galaxy , by collecting about one petabyte of data in five years @xcite ; the large synoptic survey telescope ( @xcite ) will provide about @xmath5tb / night of imaging data for ten years and petabytes / year of radio data products . |
3,031 | Suppose that you have an abstract for a scientific paper: we investigate experimentally and numerically the field - free orientation of the symmetric top molecule of methyl - iodide at high temperature using a terahertz radiation generated by a plasma induced by a two - color laser beam .
the degree of orientation is measured from the free - induction decay emitted by the sample .
the observed experimental signal is reproduced with a good accuracy by numerical simulations . .
And you have already written the first three sentences of the full article: manipulating the molecular rotational degrees of freedom in gas phase by means of laser fields remains a very attractive topic in quantum control @xcite with a wide range of applications in photochemistry extending from chemical reactivity @xcite to nanoscale design @xcite , stereochemistry @xcite , surface processing @xcite , catalysis @xcite , and attosecond molecular dynamics @xcite .
such phenomena play also a role in quantum computing @xcite and high - order harmonic generation @xcite . in this
setting , molecular alignment and orientation can be identified as crucial prerequisites before exploring more complex control scenarios @xcite ..
Please generate the next two sentences of the article | the alignment process @xcite is by now a well - established concept from both the experimental and theoretical points of view with recent extensions ranging from the deflection of aligned molecules @xcite , the introduction of planar alignment @xcite , the control of molecular unidirectional motion @xcite , the study of molecular superrotors @xcite or the analysis of dissipation effects due to molecular collisions @xcite .
the description and the control of molecular orientation are not currently at the same degree of improvement , in particular from the experimental point of view . |
3,032 | Suppose that you have an abstract for a scientific paper: a method for large scale gaussian process classification has been recently proposed based on expectation propagation ( ep ) .
such a method allows gaussian process classifiers to be trained on very large datasets that were out of the reach of previous deployments of ep and has been shown to be competitive with related techniques based on stochastic variational inference . nevertheless , the memory resources required scale linearly with the dataset size , unlike in variational methods .
this is a severe limitation when the number of instances is very large .
here we show that this problem is avoided when stochastic ep is used to train the model . .
And you have already written the first three sentences of the full article: gaussian process classifiers are a very effective family of non - parametric methods for supervised classification @xcite . in the binary case ,
the class label @xmath0 associated to each data instance @xmath1 is assumed to depend on the sign of a function @xmath2 which is modeled using a gaussian process prior . given some data @xmath3 , learning is performed by computing a posterior distribution for @xmath2 .
nevertheless , the computation of such a posterior distribution is intractable and it must be approximated using methods for approximate inference @xcite ..
Please generate the next two sentences of the article | a practical disadvantage is that the cost of most of these methods scales like @xmath4 , where @xmath5 is the number of training instances .
this limits the applicability of gaussian process classifiers to small datasets with a few data instances at most . |
3,033 | Suppose that you have an abstract for a scientific paper: we present a theoretical analysis of dilute gas bose - einstein condensates with dipolar atomic interactions under rotation in elliptical traps . working in the thomas - fermi limit
, we employ the classical hydrodynamic equations to first derive the rotating condensate solutions and then consider their response to perturbations .
we thereby map out the regimes of stability and instability for rotating dipolar bose - einstein condensates and in the latter case , discuss the possibility of vortex lattice formation .
we employ our results to propose several novel routes to induce vortex lattice formation in a dipolar condensate . .
And you have already written the first three sentences of the full article: the successful bose - einstein condensation of @xmath0cr atoms @xcite realizes for the first time bose - einstein condensates ( becs ) with significant dipole - dipole interactions .
these long - range and anisotropic interactions introduce rich physical effects , as well as new opportunities to control becs .
a basic example is how dipole - dipole interactions modify the shape of a trapped bec . in a prolate ( elongated ).
Please generate the next two sentences of the article | dipolar gas with the dipoles polarised along the long axis the net dipolar interaction is attractive , whereas for an oblate ( flattened ) configuration with the dipoles aligned along the short axis the net dipolar interaction is repulsive . as a result , in comparison to _ s_-wave becs ( which we define as systems in which atom - atom scattering is dominated by the _ s_-wave channel ) , a dipolar bec elongates along the direction of an applied polarizing field @xcite .
a full theoretical treatment of a trapped bec involves solving the gross - pitaevskii equation ( gpe ) for the condensate wave function . |
3,034 | Suppose that you have an abstract for a scientific paper: the network of interactions between hot gas , cool clouds , massive stars , and stellar remnants used in the chemodynamical modeling of the interstellar medium is investigated for the types of its solutions . in a physically consistent formulation for the energy transfer during condensation ,
oscillations due to a cyclic switching between condensation and evaporation never occur .
a closed - box system evolves in a hierarchy of equilibria : thermal balance in the cloud gas , star - formation self - regulated due to heating of the clouds by massive stars , and the balance of condensation and evaporation . except for an initial transitory phase
, the evolution of the metallicity follows that of the simple model quite closely . for galaxies with a high initial density , or
if the condensation rate is low , the metals produced by the stars may remain stored in the hot gas phase even in evolved systems with low gas fractions .
= 10000 # 1#2 aj * # 1 * , # 2 # 1#2 apj * # 1 * , # 2 # 1#2 apj suppl.ser .
* # 1 * , # 2 # 1#2 apss * # 1 * , # 2 # 1#2 a&a * # 1 * , # 2 # 1#2 a&as * # 1 * , # 2 # 1#2 araa * # 1 * , # 2 # 1#2 astr.zh .
* # 1 * , # 2 # 1#2 iau symp . *
# 1 * , # 2 # 1#2 mnras * # 1 * , # 2 # 1#2 pasj * # 1 * , # 2 # 1#2 pasp * # 1 * , # 2 # 1#2 proc.nat.acad.sci . *
# 1 * , # 2 # 1#2 rev.mex.a&a * # 1 * , # 2 _ g _ g _ c _ c _ c _ c _ g _ s _ r .
And you have already written the first three sentences of the full article: to understand the evolution of galaxies one may attempt to match the observational data by models which describe the global processes star - formation rate , gas infall , gas loss with suitable formulations . by adjusting free parameters ,
quite good fits can be achieved . however , the number of these free parameters often is uncomfortably large .
moreover , this approach may not lead to a unique identification of the dominant physical process , as the persisting g dwarf-`problem ' ( pagel & patchett 1975 ) and the formation of radial abundance gradients ( gtz & kppen 1992 ) illustrate . our chemodynamical approach ( hensler 1987 , theis et al ..
Please generate the next two sentences of the article | 1992 , samland et al .
1997 ) tries to describe as precisely as possible the known physical processes present in the interstellar medium ( ism ) and its interaction with the stars . |
3,035 | Suppose that you have an abstract for a scientific paper: present routes to produce magnetic organic - based materials adopt a common strategy : the use of magnetic species ( atoms , polyradicals , etc . ) as building blocks .
we explore an alternative approach which consists of selective hydrogenation of polycyclic aromatic hydrocarbons .
self - consistent - field ( scf ) ( hartree fock and dft ) and multi - configurational ( cisd and mcscf ) calculations on coronene and corannulene , both hexa - hydrogenated , show that the formation of stable high spin species is possible .
the spin of the ground states is discussed in terms of the hund rule and lieb s theorem for bipartite lattices ( alternant hydrocarbons in this case ) .
this proposal opens a new door to magnetism in the organic world .
= 1 .
And you have already written the first three sentences of the full article: two successful routes that are being actually followed to produce magnetic organic materials @xcite are the addition of magnetic atoms @xcite and the use of polyradicals @xcite . in particular , carbon - based nickel compounds that show spontaneous field - dependent magnetization and hysteresis at room temperature ,
have been recently synthesized @xcite . moreover
, the combination of two radical modules with different spins has allowed the obtaining of organic polymers with ferro- or antiferromagnetic ordering @xcite ..
Please generate the next two sentences of the article | research on molecules containing polyradicals goes back to the early nineties @xcite and has produced a variety of results as , for example , the synthesis of high spin organic molecules . in some of these molecules the failure of hund s rule has been demonstrated @xcite . on the other hand ,
experimental and theoretical evidence has been recently presented indicating that 5-dehydro - m - xylylene or dmx was the first example of an organic tri - radical with an open - shell doublet ground - state@xcite . |
3,036 | Suppose that you have an abstract for a scientific paper: in this paper , we study the asymptotic variance of sample path averages for inhomogeneous markov chains that evolve alternatingly according to two different @xmath0-reversible markov transition kernels@xmath1 and @xmath2 .
more specifically , our main result allows us to compare directly the asymptotic variances of two inhomogeneous markov chains associated with different kernels @xmath3 and @xmath4 , @xmath5 , as soon as the kernels of each pair @xmath6 and @xmath7 can be ordered in the sense of lag - one autocovariance . as an important application
, we use this result for comparing different data - augmentation - type metropolis hastings algorithms .
in particular , we compare some pseudo - marginal and propose a novel exact algorithm , referred to as the _ random refreshment _ algorithm , which is more efficient , in terms of asymptotic variance , than the grouped independence metropolis
hastings algorithm and has a computational complexity that does not exceed that of the monte carlo within metropolis algorithm . , .
And you have already written the first three sentences of the full article: _ markov chain monte carlo _ ( mcmc ) _ methods _ allow samples from virtually any target distribution @xmath0 , known up to a normalizing constant , to be generated . in particular , the celebrated _ metropolis hastings algorithm _ ( introduced in @xcite and @xcite )
simulates a markov chain evolving according to a reversible markov transition kernel by first generating , using some instrumental kernel , a candidate and then accepting or rejecting the same with a probability adjusted to satisfy the detailed balance condition @xcite . when choosing between several metropolis
hastings algorithms , it is desirable to be able to compare the efficiencies , in terms of the asymptotic variance of sample path averages , of different @xmath0-reversible markov chains . despite the practical importance of this question , only a few results in this direction exist the literature ..
Please generate the next two sentences of the article | peskun @xcite defined a partial ordering for finite state space markov chains , where one transition kernel has a higher order than another if the former dominates the latter on the off - diagonal ( see definition [ defipeskunordering ] ) .
this ordering was extended later by tierney @xcite to general state space markov chains and another even more general ordering , the covariance ordering , was proposed in @xcite . in general , it holds that if a homogeneous @xmath8-reversible markov transition kernel is greater than another according to one of these orderings , then the asymptotic variance of sample path averages for a markov chain evolving according to the former is smaller for all square integrable ( with respect to @xmath0 ) target functions . |
3,037 | Suppose that you have an abstract for a scientific paper: recent lattice results for the energy of gluonic excitations as a function of quark separation are shown to correspond to transverse relativistic flux tube vibration modes . for large quark separations
all states appear to degenerate into a few categories which are predicted uniquely , given the ground state .
epsf 6.5 in 8.6 in 0.0 in + 0.5 cm theodore j. allen _ and _ m. g. olsson + _ department of physics , university of wisconsin , + 1150 university avenue , madison , wi 53706 _ + sinia veseli + 0.1 cm _ fermi national accelerator laboratory , + p.o . box 500 , batavia , il 60510 _ 0.7 cm .
And you have already written the first three sentences of the full article: mesons in which the gluons are in an excited state have been discussed for some time .
there are two main pictures that have evolved for treating these excited states .
the first is the constituent gluon approach where the quarks and a gluon move in an mit bag @xcite or a potential model @xcite . the second picture envisions the quarks to be connected by a string or flux tube @xcite which has quantized transverse vibrations . in this case the flux tube can be thought of as a coherent gluonic state . in all of these models.
Please generate the next two sentences of the article | the resulting meson is analogous to the diatomic molecule where the gluonic degrees of freedom are the `` electronic state '' that can assume many levels of excitation .
each excited state yields an interaction energy that acts as an adiabatic potential in which the quarks or `` ions '' move . |
3,038 | Suppose that you have an abstract for a scientific paper: we report the observation by the _ compton gamma ray observatory _ of a spectacular flare of radio source pks1622@xmath0297 . a peak flux of @xmath1@xmath2s@xmath3 ( e @xmath4 100 mev ) was observed .
the corresponding isotropic luminosity is 2.9 erg / s .
we find that pks 1622@xmath0297 exhibits intra - day variability .
a flux increase by a factor of at least 3.6 was observed to occur in less than 7.1 hours ( with 99% confidence ) .
assuming an exponential rise , the corresponding doubling time is less than 3.8 hours .
a significant flux decrease by a factor of 2 in 9.7 hours was also observed . without beaming , the rapid flux change and large isotropic luminosity
are inconsistent with the elliot - shapiro condition ( assuming that gas accretion is the immediate source of power for the s ) .
this inconsistency suggests that the emission is beamed .
a minimum doppler factor of 8.1 is implied by the observed lack of pair - production opacity ( assuming x - rays are emitted co - spatially with the s ) . simultaneous observation by egret and osse finds a spectrum adequately fit by a power law with photon index of @xmath01.9 .
although the significance is not sufficient to establish this beyond doubt , the high - energy spectrum appears to evolve from hard to soft as a flare progresses .
# 1@xmath5 # 1@xmath6 to be published in ap j , february 20 , 1997 issue , vol .
476 quasars : general quasars : individual : pks 1622@xmath0297 gamma rays : observations .
And you have already written the first three sentences of the full article: the energetic gamma ray experiment telescope ( egret ) aboard the _ compton gamma ray observatory _ is sensitive in the energy range 30 mev to 30 gev ( thompson 1993 ) .
it has detected @xmath750 agn ( montigny 1995 , thompson 1995 , mattox 1996a ) in the blazar class ( by which we mean the ensemble of bl lac objects , high polarization quasars ( hpq ) , and optical violently variable ( ovv ) quasars ) .
the absence of pair - production absorption in the egret spectra and the fact that only sources which show parsec scale radio jet structure have been identified as egret sources indicate that the hard @xmath8-rays are emitted in a relativistic jet directed toward us ..
Please generate the next two sentences of the article | most models feature inverse compton scattering as the emission mechanism , but there is not a consensus as to the origin of the low energy photons which are scattered . it has been suggested that they might originate within the jet as synchrotron emission ( maraschi ghisellini & celotti 1992 ; bloom & marscher 1993 ) .
this is designated as the synchrotron self - compton ( ssc ) process . |
3,039 | Suppose that you have an abstract for a scientific paper: by spectrally hole burning an inhomogeneously broadened ensemble of ions while applying a controlled perturbation , one can obtain spectral holes that are functionalized for maximum sensitivity to different perturbations .
we propose to use such hole burnt structures for the dispersive optical interaction with rare - earth ion dopants whose frequencies are sensitive to crystal strain due to the bending motion of a crystal cantilever .
a quantitative analysis shows that good optical sensitivity to the bending motion is obtained if a magnetic field gradient is applied across the crystal during hole burning , and that the resulting opto - mechanical coupling strength is sufficient for observing quantum features such as zero point vibrations .
the ability to control and probe physical systems at the quantum mechanical level has been demonstrated in a variety of examples , ranging from single photons and atoms , over currents and voltages in electronic circuits to the motion of mechanical devices .
many of these systems are promising candidates for sensitive and high precision measurements and for transmission , processing and storage of quantum information , but one single system is typically not adequate for all of these functions .
this has spurred the interest in so - called hybrid system @xcite which combine physical components which are separately optimized for different tasks . outside the technical challenge of handling physically very different systems in a single laboratory experiment
, the mismatch of their physical properties ( resonance excitation frequencies , spatial overlap , and coherence time scales ) presents a main obstacle against the efficient transfer of quantum states between them .
for instance , single atoms have microscopic dipole moments and interact only weakly with physical observables of mesoscopic quantum systems which occupy orders of magnitude larger spatial volumes . one successful remedy to this weak coupling is to use ensembles of many atomic particles with....
And you have already written the first three sentences of the full article: the ac stark shift of the atomic ground state level and the phase shift of the transmitted field are both governed by the response of the two - level atomic system to the laser field , and in particular , the mean optical coherence induced in the ions .
we denote the lower and upper levels @xmath85 and @xmath86 , and we assume that we only excite the ions very weakly , i.e. , the ground state population @xmath87 to first order in the rabi frequency @xmath88 , where @xmath89 is the dipole matrix element and @xmath90 denotes the driving field amplitude .
this leads to the equation of motion for the optical coherence @xmath91 where the decoherence rate @xmath40 may include both radiative ( @xmath92 ) and non - radiative contributions , and where we have defined @xmath93 as the detuning , measured in radians per second ..
Please generate the next two sentences of the article | the steady state solution reads , @xmath94 , and the resulting macroscopic polarization of the doped cantilever ( with an ion density @xmath55 ) is then given by @xmath95 , leading to the optical phase shift and energy @xmath96 analyzed in the article .
the purpose of this appendix is to analyze the case where @xmath7 performs oscillatory motion , @xmath97 , and the strain induced coupling leads to a temporally modulated detuning , @xmath98 . due to the long lifetime of the ion coherence and excited state |
3,040 | Suppose that you have an abstract for a scientific paper: a model for charge transport in undoped , photo - excited semiconductor superlattices , which includes the dependence of the electron - hole recombination on the electric field and on the photo - excitation intensity through the field - dependent recombination coefficient , is proposed and analyzed . under dc voltage bias and high photo - excitation intensities
, there appear self - sustained oscillations of the current due to a repeated homogeneous nucleation of a number of charge dipole waves inside the superlattice .
in contrast to the case of a constant recombination coefficient , nucleated dipole waves can split for a field - dependent recombination coefficient in two oppositely moving dipoles .
the key for understanding these unusual properties is that these superlattices have a unique static electric - field domain . at the same time ,
their dynamical behavior is akin to the one of an extended excitable system : an appropriate finite disturbance of the unique stable fixed point may cause a large excursion in phase space before returning to the stable state and trigger pulses and wave trains .
the voltage bias constraint causes new waves to be nucleated when old ones reach the contact . .
And you have already written the first three sentences of the full article: nonlinear charge transport in weakly coupled , undoped , photo - excited , type - i semiconductor superlattices ( sls ) is well described by spatially discrete drift - diffusion equations.@xcite as in the much better known case of doped sls , nonlinear phenomena include formation and dynamics of electric - field domains , self - sustained oscillations of the current through voltage - biased sls , chaos , etc .
experimentally , the formation of static electric - field domains in undoped , photo - excited sls was already reported many years ago.@xcite the first experimental observation of dynamical aspects of domain formation in undoped , photo - excited sls such as self - sustained oscillations of the photo - current were reported by kwok _
_ et al.__@xcite due to the excitation condition , the oscillations were damped ..
Please generate the next two sentences of the article | subsequently , undamped self - sustained oscillations of the photo - current in undoped sls were observed for a type - ii gaas / alas@xcite and for a direct - gap gaas / alas sl.@xcite tomlinson _ _ et al.__@xcite reported the detection of undamped photo - current oscillations in an undoped gaas / al@xmath0ga@xmath1as sl , where the transport is governed by resonant tunnelling between @xmath2 states .
the evolution from a static state at low carrier densities to an oscillating state at higher carrier densities was demonstrated in an undoped , photo - excited sl by increasing the photo - excitation intensity.@xcite an investigation of the bifurcation diagrams for undoped , photo - excited sls showed the existence of a transition between periodic and chaotic oscillations.@xcite for a detailed review of the nonlinear static and dynamical properties of doped and undoped superlattices , see ref . . |
3,041 | Suppose that you have an abstract for a scientific paper: we give a criterion for an open book to contain an @xmath0-times iterated hopf plumbing summand . as an application
, we show that fibre surfaces of positive braid knots admit a trefoil plumbing structure . .
And you have already written the first three sentences of the full article: an open book is a connected orientable surface @xmath1 with boundary , together with a diffeomorphism @xmath2 fixing the boundary pointwise .
positive hopf plumbing is an operation that adds a @xmath3-handle @xmath4 to @xmath1 and composes @xmath5 with a right - handed dehn twist along an embedded circle that runs once through @xmath4 . in case an open book @xmath6
represents the @xmath7-sphere , the boundary of @xmath1 is a fibred link with monodromy @xmath5 ..
Please generate the next two sentences of the article | positive hopf plumbing was originally defined in this classical setting by stallings @xcite , where it corresponds to gluing a positive hopf band on top of a fibre surface . in this paper
, we consider positive @xmath0-plumbing , an @xmath0-times iterated version of positive hopf plumbing , as sketched in figure 1 , for @xmath8 . |
3,042 | Suppose that you have an abstract for a scientific paper: we have performed experiments of axial segregation in the oyama s drum .
we have tested binary granular mixtures during very long times .
the segregation patterns have been captured by a ccd camera and spatio - temporal graphs are created .
we report the occurence of instabilities which can last several hours ! we stress that those instabilities originate from the competition between axial and radial segregations .
we put into evidence the occurence of giant fluctuations in the fraction of grain species along the surface during the unstable periods .
granular flow : mixing , segregation and stratification , porous materials ; granular materials 45.70.mg , 81.05.rm .
And you have already written the first three sentences of the full article: the most spectacular phenomenon associated with granular matter is certainly the phase segregation that one observes when a granular mixture is shaked , poured or rotated @xcite . respectively ,
stripe @xcite , axial @xcite and radial @xcite segregation patterns have been reported .
recent experiments @xcite and theoretical models @xcite have been extensively performed in the particular case of stripe segregation . however , the least studied type of segregation is the case of the axial segregation in the so - called oyama s drum @xcite ..
Please generate the next two sentences of the article | the experiment consists in rotating a tube which is half filled with a sand mixture .
the mixture is composed by 2 granular species differing in size and having different angles of repose . due to the rotation , avalanches occur in the tube . |
3,043 | Suppose that you have an abstract for a scientific paper: during the last century , with the development of modern physics in such diverse fields as thermodynamics , statistical physics , and nuclear and particle physics , the basic principles of the evolution of stars have been successfully well understood . nowadays , a precise diagnostic of the stellar interiors is possible with the new fields of helioseismology and astroseismology .
even the measurement of solar neutrino fluxes , once a problem in particle physics , is now a powerful probe of the core of the sun .
these tools have allowed the use of stars to test new physics , in particular the properties of the hypothetical particles that constitute the dark matter of the universe . here
we present recent results obtained using this approach . .
And you have already written the first three sentences of the full article: during the last 70 years , significant progress has been achieved in the study of the physics in the interior of the sun and stars @xcite .
this advance has been possible due to the great development of several key fields of experimental and theoretical physics , such as statistical physics , magneto - hydrodynamics , particle physics , and nuclear physics , among others .
astronomers are now able to describe with high - precision the physics that takes place inside stars like the sun , as well as many other classes of stars , with masses different than that of the sun , and in quite different stages of stellar evolution . in general ,.
Please generate the next two sentences of the article | the physics of stars is well understood since the first moments of their formation , up to the most advanced stages of stellar evolution , including the formation of highly compact objects , like white dwarfs , neutron stars and black holes .
the progress in the understanding of the physical principles operating inside stars was accompanied and challenged by important developments in the observational fields of astrophysics , such as astrometry , photometry and high - resolution spectroscopy , as well as the new fields of helioseismology and asteroseismology , which create powerful tools to probe the interior of stars . |
3,044 | Suppose that you have an abstract for a scientific paper: this paper introduces algorithms for surveillance applications of wireless sensor and actor networks ( wsans ) that reduce communication cost by suppressing unnecessary data transfers .
the objective of the considered wsan system is to capture and eliminate distributed targets in the shortest possible time .
computational experiments were performed to evaluate effectiveness of the proposed algorithms .
the experimental results show that a considerable reduction of the communication costs together with a performance improvement of the wsan system can be obtained by using the communication algorithms that are based on spatiotemporal and decision aware suppression methods .
sensor and actor networks , data suppression , target tracking , surveillance applications .
And you have already written the first three sentences of the full article: wireless sensor and actor networks ( wsans ) are composed of sensor nodes and actors that are coordinated via wireless communications to perform distributed sensing and acting tasks . in wsans , sensor nodes collect information about the physical world , while actors use the collected information to take decisions and perform appropriate actions upon the environment .
the sensor nodes are usually small devices with limited energy resources , computation capabilities and short wireless communication range . in contrast , the actors are equipped with better processing capability , stronger transmission powers and longer battery life .
the number of actors in wsan is significantly lower than the number of sensor nodes @xcite ..
Please generate the next two sentences of the article | the wsans technology has enabled new surveillance applications , where sensor nodes detect targets of interest over a large area .
the information collected by sensor nodes allows mobile actors to achieve surveillance goals such as target tracking and capture . |
3,045 | Suppose that you have an abstract for a scientific paper: we present new , multiwavelength very large array observations of the 3 radio galaxies in the cluster abell 119 : 0053 - 015 , 0053 - 016 and 3c 29 .
the first two radio galaxies , which lie close to the cluster center , show a narrow - angle - tailed structure , with many twists in the tails .
the third radio source is located at the cluster periphery , and shows an undistorted fri morphology .
all three radio sources are strongly polarized at the highest frequencies , and all three show both more depolarization and higher faraday rotation measures with increasing proximity to the cluster center .
we interpret this polarization behaviour as induced by the magneto - ionized intracluster medium , whose magnetic field is estimated to be in the range 5 - 10 @xmath0 g .
27a 40l 0 1 .
And you have already written the first three sentences of the full article: the intra - cluster medium ( icm ) in clusters of galaxies is known to possess magnetic fields whose origin and properties are not yet well known .
the presence of cluster magnetic fields is demonstrated by a ) the existence of diffuse cluster - wide radio emission ( radio halo ) as revealed in some clusters ( e.g. coma , see giovannini et al .
1993 , and references therein ) , b ) the detection of inverse compton hard x - ray emission ( bagchi et al ..
Please generate the next two sentences of the article | 1998 , fusco - femiano et al . 1998 ) , c ) the study of variations of the faraday rotation of background sources shining through different lines of sight across the clusters , d ) the analysis of faraday rotation gradients in extended sources embedded within the cluster .
kim et al . ( 1991 ) analyzed the rotation measure ( rm ) of radio sources in a sample of abell clusters and found that @xmath0 g level fields are widespread in the icm , regardless whether they do or do not have a strong radio halo . |
3,046 | Suppose that you have an abstract for a scientific paper: we report on four epochs of observations of the quasar pg 1211 + 143using _ nustar_. the net exposure time is 300 ks .
prior work on this source found suggestive evidence of an `` ultra - fast outflow '' ( or , ufo ) in the fe k band , with a velocity of approximately @xmath0 .
the putative flow would carry away a high mass flux and kinetic power , with broad implications for feedback and black hole - galaxy co - evolution .
_ nustar_detects pg 1211 + 143out to 30 kev , meaning that the continuum is well - defined both through and above the fe k band .
a characteristic relativistic disk reflection spectrum is clearly revealed , via a broad fe k emission line and compton back - scattering curvature .
the data offer only weak constraints on the spin of the black hole . a careful search for ufo s show no significant absorption feature above @xmath1 confidence .
the limits are particularly tight when relativistic reflection is included .
we discuss the statistics and the implications of these results in terms of connections between accretion onto quasars , seyferts , and stellar - mass black holes , and feedback into their host environments . . .
And you have already written the first three sentences of the full article: the observation of a relation between the masses of supermassive black holes at the centers of galaxies and the stellar velocity dispersion ( @xmath2 relation ; * ? ? ?
* ; * ? ? ?
* ) suggests a direct link between black holes and their host galaxies . energy and momentum driven out from the central regions push gas and dust away , halting star formation and stopping agn fueling (; see for a review ) ..
Please generate the next two sentences of the article | the action of agn feedback could be achieved through the powerful radio jets in the kinetic mode . in the radiative mode ,
accretion disks drive powerful winds that could contribute significantly to the energy budget of the bh - galaxy system . observing the properties of such |
3,047 | Suppose that you have an abstract for a scientific paper: let @xmath0 $ ] be a degree @xmath1 polynomial .
we say @xmath2 is _ post - critically bounded _ , or pcb , if all of its critical points have bounded orbit under iteration of @xmath2 .
it is known that if @xmath3 and @xmath2 is pcb , then all critical points of @xmath2 have @xmath4-adic absolute value less than or equal to 1 .
we give a similar result for @xmath5 .
we also explore a one - parameter family of cubic polynomials over @xmath6 to illustrate that the @xmath4-adic mandelbrot set can be quite complicated when @xmath7 , in contrast with the simple and well - understood @xmath8 case .
& pdflatex .
And you have already written the first three sentences of the full article: in complex dynamics , the mandelbrot set is a source of inspiration for much current research .
this set , @xmath9 is a complicated and interesting subset of the moduli space of degree two polynomials . in the past two decades
, much research has been done on dynamical systems in a nonarchimedean setting ..
Please generate the next two sentences of the article | see , for example , @xcite . for a survey of the subject , see @xcite or @xcite . if one examines the mandelbrot set over a @xmath4-adic field , one finds the object to be much less inspiring .
for any prime @xmath4 , the @xmath4-adic mandelbrot set for quadratic polynomials as defined above , replacing @xmath10 with @xmath11 , is simply the unit disk . |
3,048 | Suppose that you have an abstract for a scientific paper: we confirm and extend our previous detection of a population of intergalactic globular clusters in abell 1185 , and report the first discovery of an intergalactic globular cluster in the nearby virgo cluster of galaxies .
the numbers , colors and luminosities of these objects can place constraints on their origin , which in turn may yield new insights to the evolution of galaxies in dense environments .
# 1_#1 _ # 1_#1 _ = # 1 1.25 in .125 in .25 in .
And you have already written the first three sentences of the full article: there are several reasons to believe that a population of intergalactic globular clusters ( igcs ) should exist outside of galaxies : \(1 ) the jeans mass at recombination was @xmath0 solar masses , and hence globular cluster sized objects could have formed wherever the local density of matter was high enough .
\(2 ) many galaxies may have met their demise over a hubble time as a result of collisions and tidal disruption .
globular clusters are likely to survive the disruption of their parent galaxy , resulting in the gradual accumulation of a population of igcs . intergalactic stars , planetary nebulae , supernovae and hii regions have already been found ; it would be surprising if there were no igcs ..
Please generate the next two sentences of the article | \(3 ) the existence of igcs might explain high specific frequencies , bimodal globular cluster metallicity distributions and other current puzzles in the study of globular cluster systems .
jordn et al . |
3,049 | Suppose that you have an abstract for a scientific paper: there is mounting evidence for the binary nature of the progenitors of gamma - ray bursts ( grbs ) . for a long grb ,
the induced gravitational collapse ( igc ) paradigm proposes as progenitor , or in - state " , a tight binary system composed of a carbon - oxygen core ( co@xmath0 ) undergoing a supernova ( sn ) explosion which triggers hypercritical accretion onto a neutron star ( ns ) companion . for a short grb
, a ns - ns merger is traditionally adopted as the progenitor .
we divide long and short grbs into two sub - classes , depending on whether or not a black hole ( bh ) is formed in the merger or in the hypercritical accretion process exceeding the ns critical mass . for long bursts , when no bh is formed we have the sub - class of x - ray flashes ( xrfs ) , with isotropic energy @xmath1 erg and rest - frame spectral peak energy @xmath2 kev . when a bh is formed we have the sub - class of binary - driven hypernovae ( bdhne ) , with @xmath3 erg and @xmath4 kev . in analogy ,
short bursts are similarly divided into two sub - classes . when no bh is formed , short gamma - ray flashes ( s - grfs ) occur , with @xmath1 erg and @xmath5 mev . when a bh is formed , the authentic short grbs ( s - grbs ) occur , with @xmath3 erg and @xmath6 mev .
we give examples and observational signatures of these four sub - classes and their rate of occurrence . from their respective rates it is possible that `` in - states '' of s - grfs and s - grbs originate from the `` out - states '' of xrfs .
we indicate two additional progenitor systems : white dwarf - ns and bh - ns .
these systems have hybrid features between long and short bursts . in the case of s - grbs and bdhne evidence
is given of the coincidence of the onset of the high energy gev emission with the birth of a kerr bh . .
And you have already written the first three sentences of the full article: on february 1974 , at the same aaas meeting in san francisco where the discovery of grbs by the vela satellites was publicly announced @xcite , the possible relation of grbs with the `` moment of gravitational collapse '' leading to a bh formation was advanced ( see * ? ? ?
@xcite considered , for definiteness , the vacuum polarization process occurring in an overcritical kerr - newman bh ( knbh ) .
evidence was given for : a ) the formation of a vast amount of @xmath7-baryon plasma ; b ) the energetics of grbs of the order of @xmath8 erg , where @xmath9 is the bh mass , implying their cosmological origin ; c ) the ultra - high energy cosmic rays with energy up to @xmath10 ev originating from such an extreme electrodynamical process ..
Please generate the next two sentences of the article | soon after , the role of an @xmath7 plasma for the origin of grbs was also considered by @xcite .
it took almost thirty years to clarify some of the analogies and differences between these two processes of @xmath7-pair creation leading , respectively , to the alternative concepts of fireball " and fireshell " @xcite . already in @xmath11 , well before the establishment of the grb cosmological nature and energetics |
3,050 | Suppose that you have an abstract for a scientific paper: the paper investigates relationship between algebraic expressions and graphs .
we consider a digraph called a square rhomboid that is an example of non - series - parallel graphs .
our intention is to simplify the expressions of square rhomboids and eventually find their shortest representations . with that end in view
, we describe the new algorithm for generating square rhomboid expressions , which improves on our previous algorithms . .
And you have already written the first three sentences of the full article: a _ graph _ @xmath0 consists of a _ _ vertex set _ _ @xmath1 and an _ _ edge set _ _ @xmath2 , where each edge corresponds to a pair @xmath3 of vertices .
a graph in which each edge has a _ weight _ associated with it is called a _ network_.
a graph @xmath4 is a _ subgraph _ of @xmath0 if @xmath5 and @xmath6 ..
Please generate the next two sentences of the article | a graph @xmath7 is a _ homeomorph _ of @xmath8 if @xmath7 can be obtained by subdividing edges of @xmath8 with new vertices .
we say that a graph @xmath9 is a _ square of a graph _ |
3,051 | Suppose that you have an abstract for a scientific paper: the rashba effect is one of the most striking manifestations of spin - orbit coupling in solids , and provides a cornerstone for the burgeoning field of semiconductor spintronics .
it is typically assumed to manifest as a momentum - dependent splitting of a single initially spin - degenerate band into two branches with opposite spin polarisation . here ,
combining polarisation - dependent and resonant angle - resolved photoemission measurements with density - functional theory calculations , we show that the two `` spin - split '' branches of the model giant rashba system bitei additionally develop disparate orbital textures , each of which is coupled to a distinct spin configuration .
this necessitates a re - interpretation of spin splitting in rashba - like systems , and opens new possibilities for controlling spin polarisation through the orbital sector . .
And you have already written the first three sentences of the full article: the ability to controllably engineer spin splittings of electronic states is a key goal in the search for spintronic materials @xcite .
a particularly successful strategy has been the lifting of spin degeneracy via spin - orbit coupling in the presence of structural inversion asymmetry . termed the rashba or
bychov - rashba effect @xcite this manifests through a spin - momentum locking of the quasiparticles , stabilising a pair of fermi surfaces which are typically assumed to exhibit counter - rotating chiral spin textures @xcite ..
Please generate the next two sentences of the article | the ability to electrostatically control the strength of such spin splitting @xcite has led to prospects for all - electrical manipulation of electron spin precession @xcite , offering new prototypical schemes of semiconductor spintronics @xcite .
the quest to practically realise such devices , and to operate them without cryogenic cooling , has motivated a major search for materials which can host stronger spin splittings than can typically be achieved in conventional semiconductors @xcite . a giant rashba - like spin splitting |
3,052 | Suppose that you have an abstract for a scientific paper: we present trends in the multilayer relaxations of several vicinals of cu(100 ) and cu(111 ) of varying terrace widths and geometry .
the electronic structure calculations are based on density functional theory in the local density approximation with norm - conserving , non - local pseudopotentials in the mixed basis representation .
while relaxations continue for several layers , the major effect concentrates near the step and corner atoms . on all surfaces the step atoms contract inwards , in agreement with experimental findings . additionally , the corner atoms move outwards and the atoms in the adjacent chain undergo large inward relaxation .
correspondingly , the largest contraction ( 4% ) is in the bond length between the step atom and its bulk nearest neighbor ( bnn ) , while that between the corner atom and bnn is somewhat enlarged .
the surface atoms also display changes in registry of upto 1.5% .
our results are in general in good agreement with leed data including the controversial case of cu(511 ) .
subtle differences are found with results obtained from semi - empirical potentials .
pacs # 61.50.ah , 68.35.bs , 68.47.de .
And you have already written the first three sentences of the full article: structural properties of regularly stepped metal surfaces have been the focus of a broad range of theoretical and experimental studies because of the eminent role they play in technologically important phenomena such as thin film growth , epitaxial layer formation , nanostructuring of material , and catalysis @xcite . according to crystallographic notation
, these surfaces are denoted by high miller indices and are called vicinals of their low miller index counterparts ( flat surfaces ) .
the presence of arrays of atomic steps separated by flat terraces creates regions of differing local coordination and makes the microscopic structure of a vicinal surface distinct from that of a flat surface . according to smoluchowski s idea of charge smoothing @xcite , for example.
Please generate the next two sentences of the article | , electronic charge densities are expected to rearrange in the vicinity of the steps , thereby causing the ion cores to relax to new configurations .
the modified electronic structure may also be expected to impact the reactivity and the nature of the force fields in the region around the steps . |
3,053 | Suppose that you have an abstract for a scientific paper: we derive a variety of exact black hole solutions in a subclass of horndeski s scalar - tensor theory possessing shift symmetry , @xmath0 , and reflection symmetry , @xmath1 .
the theory admits two arbitrary functions of @xmath2 , and our solutions are constructed without specifying the concrete form of the two functions , implying that black hole solutions in specific scalar - tensor theories found in the literature can be extended to a more general class of theories with shift symmetry .
our solutions include a black hole in the presence of an effective cosmological constant , the nariai spacetime , the lifshitz black hole , and other nontrivial solutions , all of which exhibit nonconstant scalar - field profile . .
And you have already written the first three sentences of the full article: modifying general relativity has been one of the most highlighted fields in gravitational physics in recent years .
long distance modification of gravity has been studied extensively so as to explain the current accelerated expansion of the universe ( see , _
e.g. _ , ref ..
Please generate the next two sentences of the article | @xcite for a recent review ) . more theoretically , it is interesting to ask the simple question of whether one can consistently modify general relativity to accommodate , _
e.g. _ , massive gravitons @xcite . in many cases , |
3,054 | Suppose that you have an abstract for a scientific paper: we report on microscopic tight - binding modeling of surface states in bi@xmath0se@xmath1 three - dimensional topological insulator , based on a _ _ sp__@xmath2 slater - koster hamiltonian , with parameters calculated from density functional theory .
the effect of spin - orbit interaction on the electronic structure of the bulk and of a slab with finite thickness is investigated .
in particular , a phenomenological criterion of band inversion is formulated for both bulk and slab , based on the calculated atomic- and orbital - projections of the wavefunctions , associated with valence and conduction band extrema at the center of the brillouin zone .
we carry out a thorough analysis of the calculated bandstructures of slabs with varying thickness , where surface states are identified using a quantitative criterion according to their spatial distribution .
the thickness - dependent energy gap , attributed to inter - surface interaction , and the emergence of gapless surface states for slabs above a critical thickness are investigated .
we map out the transition to the infinite - thickness limit by calculating explicitly the modifications in the spatial distribution and spin - character of the surface states wavefunction with increasing the slab thickness .
our numerical analysis shows that the system must be approximately forty quintuple - layers thick to exhibit completely decoupled surface states , localized on the opposite surfaces .
these results have implications on the effect of external perturbations on the surface states near the dirac point . .
And you have already written the first three sentences of the full article: topological insulator @xcite ( ti ) materials host on their boundaries a novel type of topological states of quantum matter , which , unlike the quantum hall state , exist without the breaking of time - reversal symmetry .
@xcite theoretical prediction and subsequent experimental demonstration of these topological states in both two- @xcite ( 2d ) and three - dimensional @xcite ( 3d ) systems have given rise to what is now one of the most rapidly developing fields in condensed matter physics .
apart from providing a test platform for fundamental concepts , the study of tis holds promise for novel applications in materials science and chemistry , @xcite spintronics @xcite and quantum computation ..
Please generate the next two sentences of the article | @xcite however , to be able to fully explore the potential of tis , it is essential to have a detailed knowledge of the nature and properties of topological surface states in real ti materials , @xcite as well as a quantitative understanding of how they respond to external perturbations .
@xcite experimentally , these questions are being addressed with advanced surface - sensitive experimental probes , such as spin- and angle - resolved photoemission spectroscopy @xcite [ ( sr)-arpes ] and scanning tunneling microscopy @xcite ( stm ) . |
3,055 | Suppose that you have an abstract for a scientific paper: unsteady activity of @xmath0-ray burst sources leads to internal shocks in their emergent relativistic wind .
we study the emission spectra from such shocks , assuming that they produce a power - law distribution of relativistic electrons and posses strong magnetic fields .
the synchrotron radiation emitted by the accelerated electrons is compton up - scattered multiple times by the same electrons .
a substantial component of the scattered photons acquires high energies and produces @xmath1 pairs .
the pairs transfer back their kinetic energy to the radiation through compton scattering .
the generic spectral signature from pair creation and multiple compton scattering is highly sensitive to the radius at which the shock dissipation takes place and to the lorentz factor of the wind .
the entire emission spectrum extends over a wide range of photon energies , from the optical regime up to tev energies . for reasonable values of the wind parameters ,
the calculated spectrum is found to be in good agreement with the burst spectra observed by batse .
submitted to _ apj letters _ , october 1997 .
And you have already written the first three sentences of the full article: the detection of feii and mgii absorption lines at a redshift of @xmath2 in the optical spectrum of gb970508 ( metzger et al .
1997 ) , provided the first confirmation that @xmath0-ray bursts ( grbs ) originate at cosmological distances .
most of the qualitative properties of cosmological grbs are explained by the fireball model ( see e.g. , goodman 1986 ; paczyski 1986 ; mszros & rees 1993 [ mr ] ) . in this model ,.
Please generate the next two sentences of the article | a compact ( @xmath3 cm ) source releases an energy of @xmath4 erg over a duration @xmath5 seconds with a negligible baryonic contamination ( @xmath6 ) .
unsteady activity of the source results in a wind composed of many thin layers ( fireball shells ) of varying energy and baryonic mass . within each shell |
3,056 | Suppose that you have an abstract for a scientific paper: two separate statistical tests are applied to the agasa and preliminary auger cosmic ray energy spectra in an attempt to find deviation from a pure power - law .
the first test is constructed from the probability distribution for the maximum event of a sample drawn from a power - law .
the second employs the tp - statistic , a function defined to deviate from zero when the sample deviates from the power - law form , regardless of the value of the power index .
the agasa data show no significant deviation from a power - law when subjected to both tests . applying these tests to the auger spectrum
suggests deviation from a power - law .
however , potentially large systematics on the relative energy scale prevent us from drawing definite conclusions at this time . high energy cosmic ray flux
power - law tp - statistic .
And you have already written the first three sentences of the full article: nature offers a wide range of phenomena characterized by power - law distributions : diameter of moon craters , intensity of solar flares , the wealth of the richest people@xcite and intensity of terrorist attacks@xcite , to name a few .
these distributions are so - called _ heavy - tailed _ , where the fractional area under the tail of the distribution is larger than that of a gaussian and there is thus more chance for samples drawn from these distributions to contain large fluctuations from the mean . anatomical defects
aside , the cosmic ray ( cr ) energy spectrum follows a power - law for over ten orders of magnitude ..
Please generate the next two sentences of the article | the predicted abrupt deviation at the very highest energies ( the gzk - cutoff@xcite ) has generated a fury of theoretical and experimental work in the past half century .
recently , bahcall@xcite and waxman ( 2003 ) have asserted that the observed spectra ( except agasa ) are consistent with the expected flux suppression above @xmath0ev . |
3,057 | Suppose that you have an abstract for a scientific paper: in this letter we consider the superradiant phase transition of a two - component fermi gas in a cavity across a feshbach resonance .
it is known that quantum statistics plays a crucial role for the superradiant phase transition in atomic gases ; in contrast to bosons , in a fermi gas this transition exhibits strong density dependence .
we show that across a feshbach resonance , while the two - component fermi gas passes through the bec - bcs crossover , the superradiant phase transition undergoes a corresponding crossover from a fermionic behavior on the weakly interacting bcs side , to a bosonic behavior on the molecular bec side .
this intricate statistics crossover makes the superradiance maximally enhanced either in the unitary regime for low densities , in the bcs regime for moderate densities close to fermi surface nesting , or in the bec regime for high densities .
recent experiment has combined atomic bose - einstein condensates and cavity quantum electrodynamics together where atom - light interactions are strongly enhanced @xcite . a superradiant phase transition driven by external pumping field has been observed , across which atoms form a density - wave order @xcite , and roton mode softening has been found in the vicinity of this superradiant phase transition @xcite .
theoretical studies have extended to investigate noninteracting fermi gases inside a cavity @xcite .
it is shown that the fermi statistics plays a crucial role in the superrandiant phase transition at moderate and high densities @xcite . at moderate densities
, fermi surface displays a nesting structure and strongly enhances superradiance , when the momentum of the cavity light field matches the nesting momentum .
while at high densities , pauli blocking effect forbids a large part of atom - light scattering processes , and consequently , strongly suppresses superradiance .
the strong density dependence marks the major difference between superradiances in ideal fermi gases and bose gases . during the past....
And you have already written the first three sentences of the full article: * model parameters . * the single fermion hamiltonian eq .
( [ fh ] ) is obtained by adiabatically integrating out all the electronic excitation states of the atoms in the rotating wave frame .
the parameters in eq ..
Please generate the next two sentences of the article | ( [ fh ] ) are related to the experimental tunable parameters as @xmath116 , @xmath117 and @xmath118 . here
@xmath119 is the pumping field strength , @xmath120 is the pumping laser frequency detuning with respect to electronic transitions of atoms , and @xmath121 is the coupling strength between the cavity mode and the fermions . * mean field equation for fermi superfluids . * |
3,058 | Suppose that you have an abstract for a scientific paper: recent analyses of the stellar stream of the sagittarius dwarf galaxy have claimed that the kinematics and three - dimensional location of the m - giant stars in this structure constrain the dark matter halo of our galaxy to possess a triaxial shape that is extremely flattened , being essentially an oblate ellipsoid oriented perpendicular to the galactic disk . using a new stream - fitting algorithm , based on a markov chain monte carlo procedure
, we investigate whether this claim remains valid if we allow the density profile of the milky way halo greater freedom .
we find stream solutions that fit the leading and trailing arms of this structure even in a spherical halo , although this would need a rising galactic rotation curve at large galactocentric radius .
however , the required rotation curve is not ruled out by current constraints .
it appears therefore that for the milky way , halo triaxiality , despite its strong theoretical motivation , is not required to explain the sagittarius stream .
this degeneracy between triaxiality and the halo density profile suggests that in future endeavors to model this structure , it will be advantageous to relax the strict analytic density profiles that have been used to date . .
And you have already written the first three sentences of the full article: in standard @xmath0 cold dark matter ( @xmath0-cdm ) cosmology @xcite galaxies form within dark matter halos that coalesce through repeated mergers .
high resolution pure cdm simulations give rise to significantly triaxial galaxy halos , that become progressively less triaxial towards lower sizes and masses due to the increased dynamical age of the lower mass structures @xcite .
the inclusion of baryons in galaxy formation simulations alters dramatically the behavior of the central regions of the halo , which added to the effect of merging satellites makes the central halo become rounder @xcite . in the milky way , we have perhaps the best opportunity to constrain the shape of any dark matter distribution ..
Please generate the next two sentences of the article | one particularly promising strategy to accomplish this , and which is generally not possible in extragalactic systems , is to use streams of stars to probe the global potential .
the streams of low - mass satellites follow fairly closely the centre of mass orbit of their progenitor , and with careful modeling it is possible to find a solution for the stream structure within a galactic mass distribution . |
3,059 | Suppose that you have an abstract for a scientific paper: we explore the collective electromagnetic response in atomic clusters of various sizes and geometries .
our aim is to understand , and hence to control , their dielectric response , based on a fully quantum - mechanical description which captures accurately their relevant collective modes .
the electronic energy levels and wave functions , calculated within the tight - binding model , are used to determine the non - local dielectric response function .
it is found that the system shape , the electron filling and the driving frequency of the external electric field strongly control the resonance properties of the collective excitations in the frequency and spatial domains .
furthermore , it is shown that one can design spatially localized collective excitations by properly tailoring the nanostructure geometry . .
And you have already written the first three sentences of the full article: recent advances in nanoscience have created a vast number of experimentally accessible ways to configure atomic and molecular clusters into different geometries with strongly varying physical properties .
specifically , exquisite control of the shape and size of atomic and molecular clusters has made it now possible to investigate the collective electromagnetic response of ultra - small metal and semiconductor particles.@xcite the aim of this study is to model and examine plasmonic excitations in such structures , and thus to gain an understanding of the quantum - to - classical crossover of collective modes with increasing cluster size .
there is obvious technological relevance to tunable collective modes in nanostructures ..
Please generate the next two sentences of the article | for example , surface plasmon resonances in metallic nanospheres and films have been found to be highly sensitive to nearby microscopic objects , and hence are currently investigated for potential sensing applications.@xcite in this context , it is desirable to design customized nanostructures with specifically tailored resonance properties,@xcite and this study is intended to be a first step into this direction .
it is natural to expect that in many cases the electromagnetic response of nanoclusters is considerably different from the bulk . in particular for very small clusters , |
3,060 | Suppose that you have an abstract for a scientific paper: using semi - analytic modeling techniques , we calculate the luminosity function of galaxy populations residing in cold dark matter halos of different mass .
we pay particular attention to the influence of the reionization of the universe on the number of faint galaxies and to the effects of dynamical friction and tidal limitation of satellites on the number of bright galaxies .
we find substantial differences in the shapes of the galaxy luminosity functions in halos of different mass which reflect generic features of the cold dark matter model of galaxy formation and thus offer the opportunity to test it .
we then consider how the individual halo luminosity functions combine together to produce the global luminosity function .
surprisingly , the global function ends up having a shallower faint end slope than those of the constituent halo luminosity functions .
we compare our model predictions with the limited datasets compiled by .
we find good agreement with the luminosity functions measured in the virgo and coma clusters but significant disagreement with the luminosity functions measured in the local group and ursa minor cluster .
we speculate on possible inadequacies in our modeling and in the existing observational samples .
the luminosity functions of galaxies in groups and clusters identified in the 2df and sdss galaxy redshift surveys offer the prospect of testing galaxy formation models in detail . .
And you have already written the first three sentences of the full article: understanding the galaxy luminosity function has been a goal of galaxy formation theory for several decades ( e.g. ) .
a particularly interesting question is whether the luminosity function is universal or whether it depends on environmental factors such as the mass of the dark halo that hosts a particular galaxy population .
considerable attention has been paid to the faint end of the luminosity function which has a much flatter slope than the low mass end of the halo mass function predicted in cold dark matter ( cdm ) models of galaxy formation ( e.g. ) ..
Please generate the next two sentences of the article | the early work of showed that the number of faint galaxies must have been strongly affected by feedback processes that prevented most of the gas from cooling in small halos at early times .
some likely feedback mechanisms , such as the injection of energy into the interstellar medium in the course of stellar evolution , depend on the internal properties of the galaxy and so their effects may be expected to be independent of the large - scale environment . |
3,061 | Suppose that you have an abstract for a scientific paper: pull - tabbing is an evaluation approach for functional logic computations , based on a graph transformation recently proposed , which avoids making irrevocable non - deterministic choices that would jeopardize the completeness of computations .
in contrast to other approaches with this property , it does not require an upfront cloning of a possibly large portion of the choice s context .
we formally define the pull - tab transformation , characterize the class of programs for which the transformation is intended , extend the computations in these programs to include the transformation , and prove the correctness of the extended computations . functional logic programming , non - determinism , graph rewriting
, pull - tabbing to 0pt -4.5 in to 0pt draft we d mar 30 17:21:24 pdt 2011 .
And you have already written the first three sentences of the full article: functional logic programming @xcite joins in a single paradigm the features of functional programming with those of logic programming .
logic programming contributes logic variables that are seamlessly integrated in functional computations by narrowing .
the usefulness and elegance of programming with narrowing is presented in @xcite . at the semantics level.
Please generate the next two sentences of the article | free variables are equivalent to _ non - deterministic functions _
@xcite , i.e. , functions that for some arguments may return any one of many results . |
3,062 | Suppose that you have an abstract for a scientific paper: we developed a new lattice boltzmann method that allows the simulation of two - phase flow of viscoelastic liquid mixtures .
we used this new method to simulate a bubble rising in a viscoelastic fluid and were able to reproduce the experimentally observed cusp at the trailing end of the bubble .
+ + .
And you have already written the first three sentences of the full article: the study of viscoelastic fluids is of great scientific interest and industrial relevance .
viscoelastic fluids are fluids that show not only a viscous flow response to an imposed stress , as do newtonian fluids , but also an elastic response .
viscoelastic effects are almost universally observed in polymeric liquids@xcite , where they often dominate the flow behavior ..
Please generate the next two sentences of the article | they can also be observed in simple fluids , especially in high frequency testing@xcite or in under - cooled liquids@xcite . because most research into viscoelastic liquids , especially that with an eye toward engineering applications , is directed toward polymeric liquids , the viscoelastic behavior of simple liquids is not as well known among researchers .
the fact that the manifestation of viscoelasticity does not require the presence of polymer molecules is at the heart of our approach , as will become clear in the description of the viscoelastic model . |
3,063 | Suppose that you have an abstract for a scientific paper: we made mid - infrared observations of the 10m@xmath0 herbig be star hd200775 with the cooled mid - infrared camera and spectrometer ( comics ) on the 8.2 m subaru telescope .
we discovered diffuse emission of an elliptical shape extended in the north - south direction in @xmath11000au radius around unresolved excess emission .
the diffuse emission is perpendicular to the cavity wall formed by the past outflow activity and is parallel to the projected major axis of the central close binary orbit .
the centers of the ellipse contours of the diffuse emission are shifted from the stellar position and the amount of the shift increases as the contour brightness level decreases .
the diffuse emission is well explained in all of geometry ( the shape and the shift ) , size , and configuration by an inclined flared disk where only its surface emits the mid - infrared photons .
our results give the first well - resolved infrared disk images around a massive star and strongly support that hd200775 is formed through the disk accretion .
the disk survives the main accretion phase and shows a structure similar to that around lower - mass stars with disk atmosphere. at the same time , the disk also shows properties characteristic to massive stars such as photoevaporation traced by the 3.4 mm free - free emission and unusual silicate emission with a peak at 9.2@xmath2 m , which is shorter than that of many astronomical objects .
it provides a good place to compare the disk properties between massive and lower - mass stars . .
And you have already written the first three sentences of the full article: in these two decades , many circumstellar disks around young forming / formed stars less than several solar masses are found by direct images in the infrared / visible observations ( e.g. mccaughrean & odell 1996 ; fukagawa et al . 2004 ; fujiwara et al .
2006 ; lagage et al .
2006 ; see also web database ) ..
Please generate the next two sentences of the article | radio , infrared , and visible line observations confirmed that some disks have rotating disk kinematics as expected ( simon , dutrey , & guilloteau 2000 ; pontoppidan et al . 2008 ; acke , van den ancker , dullemond 2005 ) .
in contrast , the formation scenario for massive stars ( @xmath38m@xmath4 ) is still unclear . since , for such massive stars , the time scale for the kelvin - helmholtz contraction is shorter than that of free - fall or accretion with accretion rate similar to low mass star cases , they start releasing energy through nuclear fusion even during accretion ( palla & stahler 1993 ) . |
3,064 | Suppose that you have an abstract for a scientific paper: understanding protein structure is of crucial importance in science , medicine and biotechnology .
for about two decades , knowledge based potentials based on pairwise distances so - called `` potentials of mean force '' ( pmfs ) have been center stage in the prediction and design of protein structure and the simulation of protein folding . however , the validity , scope and limitations of these potentials are still vigorously debated and disputed , and the optimal choice of the reference state a necessary component of these potentials is an unsolved problem .
pmfs are loosely justified by analogy to the reversible work theorem in statistical physics , or by a statistical argument based on a likelihood function .
both justifications are insightful but leave many questions unanswered . here
, we show for the first time that pmfs can be seen as approximations to quantities that do have a rigorous probabilistic justification : they naturally arise when probability distributions over different features of proteins need to be combined .
we call these quantities `` reference ratio distributions '' deriving from the application of the `` reference ratio method '' .
this new view is not only of theoretical relevance , but leads to many insights that are of direct practical use : the reference state is uniquely defined and does not require external physical insights ; the approach can be generalized beyond pairwise distances to arbitrary features of protein structure ; and it becomes clear for which purposes the use of these quantities is justified .
we illustrate these insights with two applications , involving the radius of gyration and hydrogen bonding . in the latter case
, we also show how the reference ratio method can be iteratively applied to sculpt an energy funnel .
our results considerably increase the understanding and scope of energy functions derived from known biomolecular structures . .
And you have already written the first three sentences of the full article: methods for protein structure prediction , simulation and design rely on an energy function that represents the protein s free energy landscape ; a protein s native state typically corresponds to the state with minimum free energy @xcite .
so - called knowledge based potentials ( kbp ) are parametrized functions for free energy calculations that are commonly used for modeling protein structures @xcite .
these potentials are obtained from databases of known protein structures and lie at the heart of some of the best protein structure prediction methods ..
Please generate the next two sentences of the article | the use of kbps originates from the work of tanaka and scheraga @xcite who were the first to extract effective interactions from the frequency of contacts in x - ray structures of native proteins .
miyazawa and jernigan formalized the theory for contact interactions by means of the quasi - chemical approximation @xcite . |
3,065 | Suppose that you have an abstract for a scientific paper: to address the question of whether the so - called ultra compact dwarf galaxies ( ucds ) are the remnant nuclei of destroyed early - type dwarf galaxies ( des ) , we analyze the stellar population parameters of the nuclei of 34 virgo des , as well as ten virgo ucds , including one that we discovered and which we report on here .
based on absorption line strength ( lick index ) measurements , we find that nuclei of virgo des have younger stellar population ages than ucds , with averages of 5 gyr and @xmath010 gyr , respectively .
in addition to this , the metallicity also differs : de nuclei are on average more metal - rich than ucds . on the other hand , comparing the stellar population parameters at the same local galaxy density , with ucds being located in the high density cluster regions , we do not find any difference in the stellar populations of de nuclei and ucds . in those regions ,
the de nuclei are as old and as metal poor as ucds .
this evidence suggests that the virgo ucds may have formed through the stripping of de nuclei . .
And you have already written the first three sentences of the full article: since the discovery of ultra - compact dwarf galaxies ( ucds ; @xcite ; @xcite ) , it is still a complicated puzzle in extragalactic astronomy how such compact and luminous objects may have formed .
they are brighter and larger than globular clusters ( gcs ) @xcite and much smaller than early - type dwarf galaxies ( des ) in both size and luminosity .
a number of studies targeting various ucd samples in different galaxy clusters also revealed the diverse nature of ucds : fornax ucds are slightly redder on average than virgo ucds @xcite . on the other hand , it is still a matter of debate whether or not the ucds contain dark matter @xcite ..
Please generate the next two sentences of the article | this makes them very special objects to study in extragalactic astronomy , suggesting that the presence of dark matter or not can be directly related to whether ucds have a galactic origin or not .
overall it has been already noted that virgo ucds contain fairly old ( age : @xmath0 8 - 10 gyr ) and metal poor ( @xmath10.5 dex ) stellar populations ( * ? ? ? |
3,066 | Suppose that you have an abstract for a scientific paper: we established a simple thermal model of the heat flow in a large crystal detector designed for a neutrinoless double beta decay experiment .
the detector is composed of a camoo@xmath0 crystal and a metallic magnetic calorimeter ( mmc ) .
the thermal connection between the absorber and the sensor consists of a gold film evaporated on the crystal surface and gold bonding wires attached to this film and the mmc sensor .
the model describes athermal and thermal processes of heat flow to the gold film .
a successive experiment based on optimization calculations of the area and thickness of the gold film showed a significant improvement in the size and rise - time of the measured signals . .
And you have already written the first three sentences of the full article: over the last two decades , significant progress in the development of low temperature detectors for particle astrophysics applications has been made .
thermal detectors with dielectric crystal absorbers have been employed in many rare event experiments in deep underground laboratories around the world .
these detectors can be designed to have high energy resolution , achieved by using sensitive temperature sensors such as neutron transmutation doped ( ntd ) ge thermistors , transition edge sensors ( tess ) , and metallic magnetic calorimeters ( mmcs)@xcite . when semiconductor or scintillating crystals are used as the absorber , charge or light signals provide additional measurement channels along with temperature measurement ( phonon channel ) ..
Please generate the next two sentences of the article | simultaneous measurement of two different channels enables to reduce background events by different ionization or quenching factors for different particle types .
although any dielectric crystal can be used as an absorber of a thermal detector , the appropriate measurement of phonon signals is a non - trivial task . at low temperatures , |
3,067 | Suppose that you have an abstract for a scientific paper: cheptea , habiro and massuyeau constructed the lmo functor , which is defined on a certain category of cobordisms between two surfaces with at most one boundary component . in this paper , we extend the lmo functor to the case of any number of boundary components , and our functor reflects relations among the parts corresponding to the genera and boundary components of surfaces .
we also discuss a relationship with finite - type invariants and milnor invariants . .
And you have already written the first three sentences of the full article: in the early 1990s , kontsevich @xcite defined the kontsevich invariant ( the universal finite - type invariant ) of knots by the integral on the configuration space of finite distinct points in @xmath0 .
all rational - valued vassiliev invariants are recovered from the kontsevich invariant through weight systems . in the late 1990s ,
ohtsuki @xcite showed that one can consider an arithmetic expansion of the quantum @xmath1-invariant of rational homology spheres ..
Please generate the next two sentences of the article | the result of this expansion is called the perturbative @xmath1-invariant .
ohtsuki @xcite also introduced integer - valued finite - type invariants of integral homology spheres . |
3,068 | Suppose that you have an abstract for a scientific paper: the pierre auger observatory in argentina provides the largest data sample of the cosmic ray events with energy above 10@xmath0 ev .
these high energy events can be used to test our understanding of the hadronic interactions at energies beyond the reach of colliders and to probe the basic properties of these interactions such as the inelastic cross - section of proton - air collisions .
the combination of an array of surface detectors and the fluorescence telescopes of the pierre auger observatory reduces significantly the dependency of the shower energy estimation on mc simulations . despite that
, the interpretation of mass sensitive quantities such as the shower maximum in terms of chemical composition of cosmic rays still depends on the hadronic interaction models .
this contribution describes the main results of the observatory concerning the chemical composition of the cosmic rays and focuses on the problem of muon deficit in hadronic interaction models and on the estimation of proton - air cross - section from air - shower data .
report - no : edsblois/2013/56 .
And you have already written the first three sentences of the full article: the pierre auger observatory is situated in the argentinian province mendoza , close to the city of malarge .
it consists of a 3000 km@xmath1 surface detector array and a set of 24(+3 ) fluorescence telescopes .
the surface detector stations are water cherenkov tanks each equipped with 3 photomultipliers measuring light induced by electromagnetic particles and muons ..
Please generate the next two sentences of the article | six fluorescence telescopes occupy one fluorescence detector building . in total four of these buildings
are located on the array border on small hills and thus overlook the interior of the array measuring the longitudinal profile of electromagnetic shower @xcite . already in the year 2008 |
3,069 | Suppose that you have an abstract for a scientific paper: under assumption of singular behavior of invariant charge @xmath0 at @xmath1 and of large @xmath2 behavior , corresponding to the perturbation theory up to four loops , a procedure is considered of smooth matching the @xmath3-function at a boundary of perturbative and nonperturbative regions .
the procedure results in a model for @xmath4 for all @xmath5 with dimensionless parameters being fixed and dimensional parameters being expressed in terms of only one quantity @xmath6 .
the gluon condensate which is defined by the nonperturbative part of the invariant charge is calculated for two variants of true perturbative " invariant charge , corresponding to freezing option and to analytic one in nonperturbative region .
dimensional parameters are fixed by varying normalization condition @xmath7 .
it is obtained that on the boundary of perturbative region @xmath8 @xmath9 0.44 , the procedure results in nonperturbative coulomb component @xmath10 0.25 , the nonperturbative region scale @xmath11 1 gev , the model parameter @xmath12 ( 0.42 gev)@xmath13 which suits as string tension parameter , the gluon condensate appears to be close for two variants considered , @xmath14 ( 0.33 0.36 gev)@xmath15 ( for @xmath16 ) .
+ _ keywords : _ nonperturbative qcd ; gluon condensate ; running coupling constant ; infrared region .
+ pacs nos . : 12.38.-t , 12.38.aw , 11.15.tk .
And you have already written the first three sentences of the full article: a consistent description of interaction of fundamental fields both at large and short distances is one of the most important problems of qcd .
the strength of the interaction is defined by invariant charge @xmath0 ( the running coupling constant ) , which satisfies the renormalization group equation .
the purpose of the present work consists in a formulation of a model for @xmath0 for all @xmath17 , which is appropriate for description both of perturbative and of nonperturbative phenomena and needs minimal number of parameters ..
Please generate the next two sentences of the article | we assume that there exists some value @xmath18 , which characterizes the nonperturbative effects scale and the corresponding value @xmath8 @xmath19 such , that for @xmath20 and thus @xmath21 the finite loop perturbation theory is applicable and sufficient , while nonperturbative effects prevails in region @xmath22 , which contains also nonphysical singularities of the perturbation theory and so here this theory essentially needs an extension of definition . in general , the invariant charge and the beta - function as well
are depending on a renormalization scheme @xcite . for definiteness while performing calculations at @xmath23 we use @xmath24 scheme . |
3,070 | Suppose that you have an abstract for a scientific paper: we consider two nonperturbative methods originally used to derive shell model effective interactions in nuclei .
these methods have been applied to the two nucleon sector to obtain an energy independent effective interaction @xmath0 , which preserves the low momentum half - on - shell @xmath1 matrix and the deuteron pole , with a sharp cutoff imposed on all intermediate state momenta .
we show that @xmath0 scales with the cutoff precisely as one expects from renormalization group arguments .
this result is a step towards reformulating traditional model space many - body calculations in the language of effective field theories and the renormalization group .
the numerical scaling properties of @xmath0 are observed to be in excellent agreement with our exact renormalization group equation . _
pacs : _ 21.30.fe ; 13.75.cs ; 11.10.hi ;
03.65.nk + _ keywords : _ nucleon - nucleon interactions ; effective interactions ; renormalization group ; scattering theory .
And you have already written the first three sentences of the full article: there has been much work over the past decade applying the techniques of effective field theory ( eft ) and the renormalization group ( rg ) to low energy nuclear systems such as the nucleon - nucleon force , finite nuclei , and nuclear matter @xcite .
conventional nuclear force models such as the paris , bonn , and argonne potentials incorporate the same asymptotic tail generated by one pion exchange , as the long wavelength structure of the interaction is unambiguously resolved from fits to low energy phase shifts and deuteron properties . the short wavelength part of the interaction is then generated by assuming a specific dynamical model based on heavy meson exchanges , combined with phenomenological treatments at very small distances .
such approaches are necessarily model dependent , as the low energy two - nucleon properties are insufficient to resolve the short distance structure ..
Please generate the next two sentences of the article | such model dependence often appears in many - body calculations , e.g. the coester band in nuclear matter , when highly virtual nucleons probe the short distance structure of the interaction .
the eft approach eliminates the unsatisfactory model dependence of conventional force models and provides an effective description that is consistent with the low energy symmetries of the underlying strong interactions ( qcd ) . |
3,071 | Suppose that you have an abstract for a scientific paper: cette note esquisse une construction mathmatique simple et naturelle du caractre probabiliste de la mcanique quantique .
elle utilise lanalyse non standard et repose sur linterprtation due feynman , mise en avant dans certaines approches fractales , du principe dincertitude de heisenberg , cest - - dire des fluctuations quantiques . on aboutit ainsi
des quations diffrentielles stochastiques , comme dans la mcanique stochastique de nelson , dcoulant de marches alatoires infinitsimales .
_ pour citer cet article : m. fliess , c. r. acad .
sci .
paris , ser .
i 344 ( 2007 ) . _
0.5 * abstract * 0.5*probabilities and quantum fluctuations . *
this note is sketching a simple and natural mathematical construction for explaining the probabilistic nature of quantum mechanics .
it employs nonstandard analysis and is based on feynman s interpretation of the heisenberg uncertainty principle , i.e. , of the quantum fluctuations , which was brought to the forefront in some fractal approaches .
it results , as in nelson s stochastic mechanics , in stochastic differential equations which are deduced from infinitesimal random walks . _ to cite this article : m. fliess , c. r. acad .
sci .
paris , ser .
i 344 ( 2007 ) .
_ physique mathmatique , reu le * * * * * ; accept aprs rvision le + + + + + + prsent par .
And you have already written the first three sentences of the full article: we are sketching a `` simple and natural '' explanation of the probabilistic nature of quantum mechanics .
this is achieved by utilizing the mathematical formalism of nonstandard analysis and feynman s interpretation of the heisenberg uncertainty principle , i.e. , of the quantum fluctuations
. * non - technical presentation of the main ideas ..
Please generate the next two sentences of the article | * this summary is intended for readers who are not familiar with non - standard analysis .
as often in nonstandard analysis ( see , e.g. , @xcite ) , we replace a continuous time interval by an infinite `` discrete '' set of infinitely closed time instants . substituting @xmath0 to @xmath1 in the well known expression of the uncertainty principle , where @xmath2 is the position , @xmath3 the mass , @xmath4 the momentum , @xmath5 the planck constant , yields equation ( [ rhei ] ) . |
3,072 | Suppose that you have an abstract for a scientific paper: in this paper , we propose a novel high dimensional constellation design scheme for visible light communication ( vlc ) systems employing red / green / blue light emitting diodes ( rgb leds ) .
it is in fact a generalized color shift keying ( csk ) scheme which does not suffer efficiency loss due to a constrained sum intensity for all constellation symbols .
crucial lighting requirements are included as optimization constraints . to control non - linear distortion , the optical peak - to - average - power ratio ( papr ) of leds is individually constrained .
fixing the average optical power , our scheme is able to achieve much lower bit - error rate ( ber ) than conventional schems especially when illumination color is more `` unbalanced '' . when cross - talks exist among the multiple optical channels , we apply a singular value decomposition ( svd)-based pre - equalizer and redesign the constellations , and such scheme
is shown to outperform post - equalized schemes based on zero - forcing or linear minimum - mean - squared - error ( lmmse ) principles . to further reduce system ber , a binary switching algorithm ( bsa )
is employed the first time for labeling high dimensional constellation .
we thus obtains the optimal bits - to - symbols mapping . * optical wireless communication , constellation design , constellation labeling , multi - color optical , csk , im / dd . * .
And you have already written the first three sentences of the full article: in recent years , indoor visible light communication by light emitting diodes ( leds ) has attracted extensive academic attention @xcite ( and references therein ) , driven by advancements in designing and manufacturing of leds @xcite .
adoption of leds as lighting source can significantly reduce energy consumption and at the same time offering high speed wireless communication , which is the primary focus of visible light communication ( vlc ) research @xcite .
most of the existing schemes employ blue leds with a yellow phosphor coating , while with red / green / blue ( rgb ) leds higher data rate is possible because of wavelength division multiplexing . with rgb leds , color - shift keying ( csk ).
Please generate the next two sentences of the article | was recommended by the ieee 802.15.7 visible light communication task group @xcite .
a few authors have promoted this idea by designing constellations using signal processing tools . |
3,073 | Suppose that you have an abstract for a scientific paper: we present the first polynomial - time approximation schemes ( ptases ) for the following subset - connectivity problems in edge - weighted graphs of bounded genus : steiner tree , low - connectivity survivable - network design , and subset tsp .
the schemes run in @xmath0 time for graphs embedded on both orientable and non - orientable surfaces .
this work generalizes the ptas frameworks of borradaile , klein , and mathieu @xcite from planar graphs to bounded - genus graphs : any future problems shown to admit the required structure theorem for planar graphs will similarly extend to bounded - genus graphs .
glencora borradaile erik d. demaine siamak tazari .
And you have already written the first three sentences of the full article: in many practical scenarios of network design , input graphs have a natural drawing on the sphere or equivalently the plane . in most cases , these embeddings have few crossings , either to avoid digging multiple levels of tunnels for fiber or cable or to avoid building overpasses in road networks . but a few crossings are common , and can easily come in bunches where one tunnel or overpass might carry several links or roads .
thus we naturally arrive at graphs of small ( bounded ) genus , which is the topic of this paper .
we develop a ptas framework for subset - connectivity problems on edge - weighted graphs of bounded genus ..
Please generate the next two sentences of the article | in general , we are given a subset of the nodes , called _
terminals _ , and the goal is to connect the terminals together with some substructure of the graph by using cost within @xmath1 of the minimum possible cost . |
3,074 | Suppose that you have an abstract for a scientific paper: the study of conformal restriction properties in two - dimensions has been initiated by lawler , schramm and werner in @xcite who focused on the natural and important chordal case : they characterized and constructed all random subsets of a given simply connected domain that join two marked boundary points and that satisfy the additional restriction property .
the radial case ( sets joining an inside point to a boundary point ) has then been investigated by wu in @xcite . in the present paper ,
we study the third natural instance of such restriction properties , namely the `` trichordal case '' , where one looks at random sets that join three marked boundary points .
this case involves somewhat more technicalities than the other two , as the construction of this family of random sets relies on special variants of sle@xmath0 processes with a drift term in the driving function that involves hypergeometric functions .
it turns out that such a random set can not be a simple curve simultaneously in the neighborhood of all three marked points , and that the exponent @xmath1 shows up in the description of the law of the skinniest possible symmetric random set with this trichordal restriction property . .
And you have already written the first three sentences of the full article: in the present paper we further study random two - dimensional sets that satisfy the conformal invariance property combined with the restriction property , following the work of lawler , schramm and werner in @xcite and the paper of wu in @xcite .
measures that satisfy conformal restriction property were introduced and first studied by lawler , schramm and werner in @xcite : for a simply connected domain @xmath2 with two marked boundary points @xmath3 and @xmath4 ( we will say `` boundary points '' instead of prime ends in the present introduction ) , they studied a class of random simply connected and relatively closed sets @xmath5 such that @xmath6 intersects @xmath7 only at @xmath3 and @xmath4 .
such a set ( or rather , its distribution ) is said to satisfy _ chordal conformal restriction property _ if the following two conditions hold : * ( conformal invariance ) the law of @xmath6 is invariant under any conformal map from @xmath8 onto itself that leave the boundary points @xmath3 and @xmath4 invariant . * ( restriction ) for any simply connected subset @xmath9 of @xmath8 such that @xmath10 , the conditional distribution of @xmath6 given @xmath11 is equal to the image of the law of @xmath6 under @xmath12 , where @xmath12 is any conformal map from @xmath8 onto @xmath9 that leaves the points @xmath13 invariant ( property ( i ) actually ensures that if this holds for one such map @xmath12 , then it holds also for any other such map ) ..
Please generate the next two sentences of the article | see figure [ fig : two - point - restriction ] . and @xmath14 is a conformal map from @xmath15 onto @xmath8 that leaves @xmath13 invariant .
the conditional law of @xmath16 given @xmath17 is equal to the ( unconditional ) law of @xmath6 . , scaledwidth=78.0% ] it is straightforward to check that if a random set @xmath6 satisfies this chordal conformal restriction property in one simply connected domain @xmath8 with boundary points @xmath3 and @xmath4 , then if we map @xmath8 conformally to another simply connected domain @xmath18 via some fixed deterministic map @xmath19 , then @xmath20 satisfies chordal conformal restriction in @xmath21 with boundary points @xmath22 and @xmath23 ( and property ( i ) ensures that the image law depends only on the triplet @xmath24 , and not on the particular instance of @xmath19 ) . hence , it is sufficient to study this property in one particular given domain @xmath8 , such as the unit disc or the upper half - plane . |
3,075 | Suppose that you have an abstract for a scientific paper: we further the recent discussion on the relation between the star - formation rate ( sfr ) of a galaxy and the luminosity of its brightest star - cluster ( sfr vs. m@xmath0 ) .
we first show that the observed trend between sfr vs. m@xmath0 is due to the brightest cluster in a galaxy being preferentially young ( @xmath1 myr - for a constant sfr ) and hence a good tracer of the current sfr , although we give notable exceptions to this rule .
archival hst imaging of high - sfr galaxies , as well as additional galaxies / clusters from the literature , are used to further confirm the observed trend . using a series of monte carlo simulations
we show that a pure power - law mass function with index , @xmath2 , is ruled out by the current data .
instead we find that a schechter function ( i.e. a power - law with an exponential truncation at the high mass end ) provides an excellent fit to the data .
additionally , these simulations show that bound cluster formation ( in /yr ) represents only @xmath3% of the total star - formation within a galaxy , independent of the star - formation rate . from this
we conclude that there is only a single mode of cluster formation which operates over at least six orders of magnitude in the sfr .
we provide a simple model of star / cluster formation feedback within dwarf galaxies ( and star - forming complexes within spirals ) which highlights the strong impact that a massive cluster can have on its surroundings . using this relation
, we can extrapolate backwards in time in order to estimate the peak sfr of major merger galaxies , such as ngc 7252 , ngc 1316 , and ngc 3610 .
the derived sfrs for these galaxies are between a few hundred and a few thousand solar masses per year .
the inferred far infrared luminosity of the galaxies , from the extrapolated sfr , places them well within the range of ultra - luminous galaxies ( ulirgs ) and for ngc 7252 within the hyper - luminous infrared galaxy regime .
thus , we provide evidence that these post merger....
And you have already written the first three sentences of the full article: young massive star clusters , which often surpass the globular clusters in the galaxy in terms of brightness , mass , and density , are seen to result from intense episodes of star - formation in galaxies .
however , star clusters are also found in relatively quiescent , low star - formation rate ( sfr ) galaxies , albeit at much lower masses ( e.g. larsen & richtler 1999 , 2000 ) .
this difference in the types ( mass ) of clusters produced in various galactic environments has been suggested to be caused by size - of - sample effects , in which galaxies with high sfrs form proportionally more clusters , and hence are able to sample the cluster mass function out to higher masses ( larsen 2002 ) ..
Please generate the next two sentences of the article | this effect has been quantitatively observed through the use of the relation ( larsen 2002 ) , where m@xmath0 is the brightest cluster in v - band absolute magnitude , in the sense that the most luminous clusters in galaxies with high sfrs are brighter .
this trend , along with the similar log n vs. @xmath4 relation ( where n is the number of clusters brighter than a certain magnitude limit ; whitmore 2003 ) , have been used to argue for a universality of cluster formation , i.e. stochastic sampling from a universal underlying mass function . |
3,076 | Suppose that you have an abstract for a scientific paper: the mean ground state occupation number and condensate fluctuations of interacting and non - interacting bose gases confined in a harmonic trap are considered by using a canonical ensemble approach . to obtain the mean ground state occupation number and the condensate fluctuations , an analytical description for the probability distribution function of the condensate
is provided directly starting from the analysis of the partition function of the system . for the ideal bose gas , the probability distribution function
is found to be a gaussian one for the case of the harmonic trap . for the interacting bose gas , using a unified approach the condensate fluctuations are calculated based on the lowest - order perturbation method and on bogoliubov theory . it is found that the condensate fluctuations based on the lowest - order perturbation theory follow the law @xmath0 , while the fluctuations based on bogoliubov theory behave as @xmath1 . .
And you have already written the first three sentences of the full article: the experimental achievement of bose - einstein condensation ( bec ) in dilute alkali atoms @xcite , spin - polarized hydrogen @xcite and recently in metastable helium @xcite has enormously stimulated the theoretical research @xcite on the ultracold bosons . among the several intriguing questions on the statistical properties of trapped interacting bose gases , the problem of condensate fluctuations @xmath2 of the mean ground state occupation number @xmath3 is of central importance .
apart from the intrinsic theoretical interest , it is foreseeable that such fluctuations will become experimentally testable in the near future @xcite . on the other hand ,
the calculations of @xmath4 are crucial to investigate the phase collapse time of the condensate @xcite ..
Please generate the next two sentences of the article | it is well known that within a grand canonical ensemble the fluctuations of the condensate are given by @xmath5 , implying that @xmath6 becomes of order @xmath7 when the temperature approaches zero .
to avoid this sort of unphysically large condensate fluctuations , a canonical ( or a microcanonical ) ensemble has to be used to investigate the fluctuations of the condensate . on the other hand , because in the experiment the trapped atoms are cooled continuously from the surrounding , the system can be taken as being in contact with a heat bath but the total number of particles in the system is conserved . |
3,077 | Suppose that you have an abstract for a scientific paper: topologically stable structures include vortices in a wide variety of matter , such as skyrmions in ferro- and antiferromagnets , and hedgehog point defects in liquid crystals and ferromagnets .
these are characterized by integer - valued topological quantum numbers . in this context ,
closed surfaces are a prominent subject of study as they form a link between fundamental mathematical theorems and real physical systems . here
we perform an analysis on the topology and stability of equilibrium magnetization states for a thin spherical shell with easy - axis anisotropy in normal directions .
skyrmion solutions are found for a range of parameters .
these magnetic skyrmions on a spherical shell have two distinct differences compared to their planar counterpart : ( i ) they are topologically trivial , and ( ii ) can be stabilized by curvature effects , even when dzyaloshinskii - moriya interactions are absent .
due to its specific topological nature a skyrmion on a spherical shell can be simply induced by a uniform external magnetic field . .
And you have already written the first three sentences of the full article: topological methods are increasingly used to describe observed states in condensed matter systems .
prominent examples are the description of vortex textures in superfluid helium;@xcite band theory for topological insulators;@xcite topological superconductivity in a helical dirac gas@xcite and in dirac semimetals;@xcite and topological defects in liquid crystals,@xcite ferromagnets,@xciteand antiferromagnets.@xcite in this context , thin curvilinear films of ordered matter are in the focus of strongly growing interest , because in these systems a nontrivial geometry can induce topological defects in the order parameter field@xcite and can result in new effective interactions.@xcite among curvilinear films the most promising candidates for new physical effects are closed surfaces due to the natural appearance of topological invariants in the system . in this case
the normalized vector field @xmath0 defined on the surface realizes a map of the surface into a sphere @xmath1 ..
Please generate the next two sentences of the article | the degree @xmath2 of this map is an integer topological invariant,@xcite i.e. each given distribution of the vector field @xmath0 on a closed oriented surface is characterized by an integer number @xmath3 which is conserved for any continuous deformation ( homotopy ) of the field @xmath0 .
moreover , any two distributions of the field @xmath0 are topologically equivalent ( homotopic ) , i.e. they can be matched by means of a continuous deformation provided they have the same @xmath3.@xcite since a discontinuity in the physical field @xmath0 is usually energetically non - favorable , two solutions with different @xmath3 are separated by a high energy barrier . |
3,078 | Suppose that you have an abstract for a scientific paper: the calculation of accurate collision strengths for atomic transitions has been a long standing problem in quantitative spectroscopy .
most modern calculations are based on the r - matrix method and problems pertaining to the use of this method have led to a discussion of the accuracy of these results .
more in particular , based on an analysis of the spectra of ngc 3918 and ngc 6302 , clegg et al .
( 1987 ) and oliva et al .
( 1996 ) have questioned r - matrix calculations for the infrared [ nev ] fine - structure transitions . using improved flux measurements for the [ nev ] lines ,
we show that the conclusion that these collision strengths would be too high , is not correct .
the discrepancies found by clegg et al . (
1987 ) can be explained by the inaccuracy of the [ nev ] 342.6 nm flux they adopted .
the discrepancies found by oliva et al .
( 1996 ) can be explained by the inaccuracy of the _ lrs_flux for the [ nev ] 14.32 @xmath0 m line .
based on the data presented in this paper there is _ no reason _ to assume that there are any problems with the r - matrix calculations for of lennon & burke ( 1994 ) .
we show that the data are accurate at the 30 % level or better .
this confirms the validity of the close coupling method . .
And you have already written the first three sentences of the full article: the calculation of accurate collision strengths for atomic transitions has been a long standing problem in the field of quantitative spectroscopy .
any calculation involving atoms in non - lte conditions requires the knowledge of vast numbers of collision strengths in order to make these calculations realistic and accurate . until recently the computing power was simply not available to calculate collision strengths in a systematic way .
one either had to resort to simpler and more approximate methods or one had to limit the calculations to only the most important transitions ..
Please generate the next two sentences of the article | this situation has now changed with the start of the iron project ( hummer et al .
1993 ) , which aims to produce a large database of accurately calculated collision strengths . |
3,079 | Suppose that you have an abstract for a scientific paper: the determination of the normal and transverse ( frictional ) inter - particle forces within a granular medium is a long standing , daunting , and yet unresolved problem .
we present a new formalism which employs the knowledge of the external forces and the orientations of contacts between particles ( of any given sizes ) , to compute all the inter - particle forces . having solved this problem
we exemplify the efficacy of the formalism showing that the force chains in such systems are determined by an expansion in the eigenfunctions of a newly defined operator . in a highly influential paper from 2005
majmudar and behringer @xcite wrote :
inter - particle forces in granular media form an inhomogeneous distribution of filamentary force chains .
understanding such forces and their spatial correlations , specifically in response to forces at the system boundaries , represents a fundamental goal of granular mechanics .
the problem is of relevance to civil engineering , geophysics and physics , being important for the understanding of jamming , shear - induced yielding and mechanical response . "
a visual example of such force chains in a system of plastic disks is provided in fig .
[ mahesh ] . in this letter
we present a solution of this goal .
to be precise , the problem that we solve is the following : consider a granular medium with known sizes of the granules , for example the 2-dimensional systems analyzed in ref .
@xcite and shown in fig . [ mahesh ] , of @xmath0 disks of known diameters @xmath1 . given the external forces , denoted below as @xmath2 and the external torques @xmath3 exerted on the granules , and given the angular orientations of the vectors connecting the center of masses of contacting granules ( but not the distance between them ! ) , determine all the inter - particle normal and tangential forces @xmath4 and @xmath5 . the method presented below applies to granular systems in mechanical equilibrium ; the issue of instabilities and abrupt changes in the....
And you have already written the first three sentences of the full article: we consider a two - dimensional configuration of @xmath0 particles with @xmath105 contacts and @xmath57 polygons . for convenience of notation ,
only single digit particle indices are used in this example , so that the notation @xmath106 means the cartesian @xmath10 component of the unit vector from the center of particle @xmath107 to that of particle @xmath108 . + and @xmath104 matrices are shown .
arrows represent the normal vectors used to construct the @xmath19 and @xmath104 matrices ( before normalization ) ..
Please generate the next two sentences of the article | different arrow colors are for visualization purposes only . ]
the convention for ordering of the contacts is demonstrated in eq . |
3,080 | Suppose that you have an abstract for a scientific paper: bayesian networks or directed graphical models are widely used to represent complex causal systems . from observational data alone , a bayesian network can only be identified up to _ markov equivalence _ and interventional experiments are required to distinguish between markov equivalent bayesian networks .
it is therefore important to describe and understand the set of markov equivalence classes ( mecs ) and their sizes . in this paper
, we initiate the combinatorial enumeration of mecs on a fixed undirected graph , and thereby recast this important statistical problem into the language of combinatorial optimization .
combinatorially , two bayesian networks are markov equivalent if their underlying undirected graphs and their set of immoralities are the same .
we show that the np - complete minimum vertex cover problem reduces to the computation of a bayesian network with the maximum number of immoralities .
the np - hardness of this problem shows the complexity of enumerating mecs from the perspective of combinatorial optimization .
we then solve this enumeration problem for classically studied families of graphs including paths , cycles , and some types of complete bipartite graphs , trees , and circulants .
we also provide tight bounds on the number and size of mecs on a given tree .
these bounds exactly parallel the well - known bounds for the independent set problem .
finally , a computer program was written to analyze the enumeration problem on all graphs with at most 10 nodes and all triangle - free graphs with at most @xmath0 nodes .
the results show a trade - off between degree and clustering coefficient with respect to the number of mecs and their sizes .
in addition , this program established that the frequency vector consisting of the number of mecs of each size uniquely determines the undirected graph . .
And you have already written the first three sentences of the full article: bayesian networks or graphical models based on directed acyclic graphs ( dags ) are widely used to represent complex causal systems in applications ranging from computational biology to epidemiology , and sociology @xcite .
a dag entails a set of conditional independence relations through the markov properties .
two dags are said to be _ markov equivalent _ if they entail the same conditional independence relations . in general , observational data.
Please generate the next two sentences of the article | can only identify a dag up to markov equivalence . for statistical causal inference it is therefore important to enumerate and describe the set of markov equivalence classes ( mecs ) and their sizes .
if the mecs are large in size , then causal inference algorithms that operate in the space of mecs as compared to dags could significantly increase efficiency . |
3,081 | Suppose that you have an abstract for a scientific paper: we consider a quantum graph consisting of a ring with rashba hamiltonian and an arbitrary number of semi - infinite wires attached .
we describe the scattering matrix for this system and investigate spin filtering for a three terminal device . .
And you have already written the first three sentences of the full article: much work has been done on spin related transport properties of nanoelectronic devices resulting in interesting applications , for example the so called spin field effect transistor proposed by datta and das @xcite .
there has been particular interest in using the rashba effect to manipulate the spin degree of freedom in such systems @xcite . in this paper
we model a simple system exhibiting the rashba effect , viz . a ring with rashba hamiltonian attached to an arbitrary number of ` free ' wires , using so called solvable models @xcite ..
Please generate the next two sentences of the article | this means that we approximate the system by a
one dimensional |
3,082 | Suppose that you have an abstract for a scientific paper: the force - free parameter @xmath0 , also known as helicity parameter or twist parameter , bears the same sign as the magnetic helicity under some restrictive conditions .
the single global value of @xmath0 for a whole active region gives the degree of twist per unit axial length .
we investigate the effect of polarimetric noise on the calculation of global @xmath0 value and magnetic energy of an analytical bipole .
the analytical bipole has been generated using the force - free field approximation with a known value of constant @xmath0 and magnetic energy .
the magnetic parameters obtained from the analytical bipole are used to generate stokes profiles from the unno - rachkovsky solutions for polarized radiative transfer equations .
then we add random noise of the order of 10@xmath1 of the continuum intensity ( i@xmath2 ) in these profiles to simulate the real profiles obtained by modern spectropolarimeters like hinode ( sot / sp ) , svm ( uso ) , asp , dlsp , polis , solis etc .
these noisy profiles are then inverted using a milne - eddington inversion code to retrieve the magnetic parameters .
hundred realizations of this process of adding random noise and polarimetric inversion is repeated to study the distribution of error in global @xmath0 and magnetic energy values .
the results show that : ( 1 ) .
the sign of @xmath0 is not influenced by polarimetric noise and very accurate values of global twist can be calculated , and ( 2 ) .
accurate estimation of magnetic energy with uncertainty as low as 0.5% is possible under the force - free condition . .
And you have already written the first three sentences of the full article: helical structures in the solar features like sunspot whirls were reported long back by george e. hale in 1925 @xcite .
he found that about 80% of the sunspot whirls were counterclockwise in the northern hemisphere and clockwise in the southern hemisphere .
later , in 1941 the result was confirmed by richardson @xcite by extending the investigation over four solar cycles ..
Please generate the next two sentences of the article | this hemispheric pattern was found to be independent of the solar cycle . since the 90 s
, the subject has been rejuvenated and this hemispheric behaviour independent of sunspot cycle is claimed to be observed for many of the solar features like active regions @xcite , filaments @xcite , coronal loops @xcite , interplanetary magnetic clouds ( imcs ) @xcite , coronal x - ray arcades @xcite and network magnetic fields @xcite etc . |
3,083 | Suppose that you have an abstract for a scientific paper: in this article we discuss the modelling of elastic and electromagnetic wave propagation through one- and two - dimensional structured piezoelectric solids . + dispersion and the effect of piezoelectricity on the group velocity and positions of stop bands
are studied in detail .
we will also analyze the reflection and transmission associated with the problem of scattering of an elastic wave by a heterogeneous piezoelectric stack .
special attention is given to the occurrence of transmission resonances in finite stacks and their dependence on a piezoelectric effect .
+ a 2d doubly - periodic piezoelectric checkerboard structure is subsequently introduced , for which the dispersion surfaces for bloch waves have been constructed and analysed , with the emphasis on the dynamic anisotropy and special features of standing waves within the piezoelectric structure . .
And you have already written the first three sentences of the full article: the work of professor sabina on modelling of composite media and , in particular , piezoelectric heterogeneous solids has made a significant impact and addressed highly challenging problems of wave propagation and homogenisation approximations , which are extremely important in a wide range of applications in physics , mechanics and engineering .
the classical work by sabina and willis @xcite on scattering of sh waves by a rough half - space introduced a new modelling approach to important applications in problems of geophysics .
widely used self - consistent analysis of wave propagation in composites was developed by sabina and willis in @xcite ..
Please generate the next two sentences of the article | significant results on homogenisation of magneto - electro - elastic composites and magneto - electric coupling have been published in @xcite and @xcite .
piezoelectric composites that are made of piezoelectric ceramics are widely used in many applications in physics and engineering @xcite . |
3,084 | Suppose that you have an abstract for a scientific paper: spectra of four non - magnetic chemically peculiar late b type stars ( hgmn ) stars are analysed to detect periodic spectral line variations ( lpvs ) .
a procedure developed to study lpvs in slowly pulsating b stars has been adopted as pulsational properties of hgmn stars should be expected to be similar . in the preliminary results discussed here no conclusive evidence for periodic lpvs was uncovered .
a more sensitive re - analysis of the data is under way . .
And you have already written the first three sentences of the full article: hgmn stars are chemically peculiar stars for which periodic variability has not been found as of yet .
searches for variability have been made mostly photometrically though some studies of spectral variability have also been attempted .
historically , several hgmn stars have been claimed to be variable but variability as yet to be confirmed in any of them @xcite ..
Please generate the next two sentences of the article | a large number of hgmn stars were observed as part of the hipparcos mission but no periodic variability was detected .
the maximum permitted amplitude can in many cases be expected to be at most a few mmag . |
3,085 | Suppose that you have an abstract for a scientific paper: in this paper , we inspect well known population genetics and social dynamics models . in these models , interacting individuals , while participating in a self - organizing process , give rise to the emergence of complex behaviors and patterns .
while one main focus in population genetics is on the adaptive behavior of a population , social dynamics is more often concerned with the splitting of a connected array of individuals into a state of global polarization , that is , the emergence of speciation . applying computational and mathematical tools
we show that the way the mechanisms of selection , interaction and replacement are constrained and combined in the modeling have an important bearing on both adaptation and the emergence of speciation . differently
( un)constraining the mechanism of individual replacement provides the conditions required for either speciation or adaptation , since these features appear as two opposing phenomena , not achieved by one and the same model .
even though natural selection , operating as an external , environmental mechanism , is neither necessary nor sufficient for the creation of speciation , our modeling exercises highlight the important role played by natural selection in the interplay of the evolutionary and the self organization modeling methodologies .
_ keywords _ : * emergence*,*self - organization*,*agent based models * , * speciation * , * markov chains*. _ msc : _
37l60 , 37n25 , 05c69 . .
And you have already written the first three sentences of the full article: there are two important phenomena observed in evolutionary dynamical systems of any kind : _ self - organization _ and _ emergence_. both phenomena are the exclusive result of endogenous interactions of the individual elements of an evolutionary dynamical system .
emergence characterizes the patterns that are situated at a higher macro level and that arise from interactions taking place at the lower micro level of the system .
self - organization , besides departing from the individual micro interactions , implies an increase in order of the system , being usually associated to the promotion of a specific functionality and to the generation of patterns ..
Please generate the next two sentences of the article | typically , complex patterns emerge in a system of interacting individuals that participate in a self - organizing process .
self - organization is more frequently related to the process itself , while emergence is usually associated to an outcome of the process . |
3,086 | Suppose that you have an abstract for a scientific paper: this paper is dedicated to the numerical study of the optimization of an industrial launcher integration process .
it is an original case of inventory - production system where a calendar plays a crucial role .
the process is modeled using the markov decision processes ( mdps ) framework .
classical optimization procedures for mdps can not be used because of specificities of the transition law and cost function .
two simulation - based algorithms are tuned to fit this special case .
we obtain a non trivial optimal policy that can be applied in practice and significantly outperforms reference policies . .
And you have already written the first three sentences of the full article: the general class of inventory - production systems is often associated to cost optimization problems . indeed , one must deal with three major matters : the storage of components , the possible random behavior of the manufacturing process and random clients demand @xcite . the controller must decide which production rate of the components fits best . a too slow production rate leads to low stock levels but it might not meet clients demand . on the opposite , a fast production rate does meet the demand , but may raise stock levels .
one must then find a balance between both to minimize costs .
this paper focuses on the optimization of a real - life industrial launcher integration process studied in collaboration with airbus defence and space ..
Please generate the next two sentences of the article | clients order a certain number of launches to be performed at specific dates .
the controller has to determine the production rates in order to minimize costs . |
3,087 | Suppose that you have an abstract for a scientific paper: we study the heat conduction of the spin-@xmath0 @xmath1 chain in finite magnetic fields where magnetothermal effects arise . due to the integrability of this model ,
all transport coefficients diverge , signaled by finite drude weights . using exact diagonalization and mean - field theory
, we analyze the temperature and field dependence of the thermal drude weight for various exchange anisotropies under the condition of zero magnetization - current flow .
first , we find a strong magnetic field dependence of the drude weight , including a suppression of its magnitude with increasing field strength and a non - monotonic field - dependence of the peak position .
second , for small exchange anisotropies and magnetic fields in the massless as well as in the fully polarized regime the mean - field approach is in excellent agreement with the exact diagonalization data .
third , at the field - induced quantum critical line between the para- and ferromagnetic region we propose a universal low - temperature behavior of the thermal drude weight . .
And you have already written the first three sentences of the full article: transport properties of one - dimensional spin-@xmath0 systems are currently at the focus of active research .
this has been motivated by the experimental manifestation of significant contributions to the thermal conductivity originating from magnetic excitations @xcite , stimulating intensive theoretical work@xcite .
strong theoretical efforts@xcite have been devoted to the question of possible ballistic thermal transport in generic spin models such as spin ladders , frustrated chains , and dimerized chains . such ballistic transport would be characterized by a finite thermal drude weight ..
Please generate the next two sentences of the article | recent numerical and analytical studies indicate that in pure but _
nonintegrable _ spin models , the thermal drude weight scales to zero in the thermodynamic limit implying that the thermal current is likely to have a finite intrinsic life - time@xcite . |
3,088 | Suppose that you have an abstract for a scientific paper: we provide unified phenomenological description of magnetooptic effects being linear and quadratic in magnetization .
the description is based on few principal spectra , describing elements of permittivity tensor up to the second order in magnetization .
each permittivity tensor element for any magnetization direction and any sample surface orientation is simply determined by weighted summation of the principal spectra , where weights are given by crystallographic and magnetization orientations .
the number of principal spectra depends on the symmetry of the crystal . in cubic crystals owning point symmetry
we need only four principal spectra . here
, the principal spectra are expressed by _
ab - initio _
calculations for bcc fe , fcc co and fcc ni in optical range as well as in hard and soft x - ray energy range , _
i.e. _ at the 2@xmath0- and 3@xmath0-edges .
we also express principal spectra analytically using modified kubo formula .
there is a vast number of physical phenomena proportional to quadratic form of magnetization . in case of dc transport phenomena ,
the most well - known examples are anisotropy magnetoresistance ( amr ) @xcite or longitudinal hall effect @xcite . within the magnetooptic community
, the field of magnetooptic effects quadratic in magnetization is complicated by incredible number of nomenclature , being called cotton - mouton effect , voigt effect , quadratic magnetooptic kerr effect ( qmoke ) @xcite , magnetic linear birefringence , x - ray magnetic linear dichroism ( xmld ) @xcite , magnetic double refraction , magnetooptic orientation effect , magnetooptic anisotropy , hubert - schfer effect or magnetorefractive effect @xcite .
the nomenclature is not strictly defined , however it refers either to type of samples ( liquid , gas , solid state ) or it refers to experimental configurations of the setup ( namely detecting change of light intensity or detecting change of polarization state upon variation of magnetization direction ) .
although those....
And you have already written the first three sentences of the full article: the optical or conductivity properties of generally anisotropic material are described by ( generally complex ) permittivity @xmath11 or conductivity @xmath10 tensor , being mutually related by ( in si units ) @xmath13 , where @xmath14 being kronecker delta and @xmath15 light frequency ( i.e. @xmath16 corresponds to d.c .
current ) .
onsager relations require antisymmetry in magnetization direction , @xmath17 ..
Please generate the next two sentences of the article | as various magnetization direction causes small perturbation to the crystal optical properties , @xmath11 , they can be expressed as taylor series of permittivity tensor in direction of @xmath18 @xcite @xmath19 where superscripts denote zeroth , first , second etc .
order in magnetization . |
3,089 | Suppose that you have an abstract for a scientific paper: complex network approaches have been recently developed as an alternative framework to study the statistical features of time - series data .
we perform a visibility - graph analysis on both the daily and monthly sunspot series .
based on the data , we propose two ways to construct the network : one is from the original observable measurements and the other is from a negative - inverse - transformed series .
the degree distribution of the derived networks for the strong maxima has clear non - gaussian properties , while the degree distribution for minima is bimodal .
the long - term variation of the cycles is reflected by hubs in the network which span relatively large time intervals . based on standard network structural measures , we propose to characterize the long - term correlations by waiting times between two subsequent events .
the persistence range of the solar cycles has been identified over 151000 days by a power - law regime with scaling exponent @xmath0 of the occurrence time of the two subsequent and successive strong minima . in contrast , a persistent trend is not present in the maximal numbers , although maxima do have significant deviations from an exponential form .
our results suggest some new insights for evaluating existing models . the power - law regime suggested by the waiting times
does indicate that there are some level of predictable patterns in the minima . .
And you have already written the first three sentences of the full article: solar - cycle prediction , _
i.e. _ forecasting the amplitude and/or the epoch of an upcoming maximum is of great importance as solar activity has a fundamental impact on the medium - term weather conditions of the earth , especially with increasing concern over the various climate change scenarios .
however , predictions have been notoriously wayward in the past @xcite ..
Please generate the next two sentences of the article | there are basically two classes of methods for solar cycle predictions : empirical data - analysis - driven methods and methods based on dynamo models .
most successful methods in this regard can give reasonably accurate predictions only when a cycle is well advanced ( _ e.g. , _ three years after the minimum ) or with the guidance from its past @xcite . |
3,090 | Suppose that you have an abstract for a scientific paper: nanostructured superconductor / ferromagnet heterocontacts are studied in the different transport regimes of point - contact spectroscopy .
direct measurements of the nanocontact size by scanning electron microscopy allow a comparison with theoretical models for contact - size estimates of heterocontacts .
our experimental data give evidence that size estimates yield reasonable values for the point - contact diameter @xmath0 as long as the samples are carefully characterized with respect to the local electronic parameters . .
And you have already written the first three sentences of the full article: point - contact spectroscopy ( pcs ) has long been known as a method to study the interactions of electrons with other excitations in metals .
@xcite the interpretation of the observed characteristics in point - contact ( pc ) spectra is usually difficult because most often contacts are made by the needle - anvil or shear technique and are not microscopically well - defined with respect to contact size and geometry , structure , and local electronic parameters .
recently , andreev reflection at point contacts was used to extract values of the transport spin polarization @xmath1 out of spectra measured on superconductor / ferromagnet ( s / f ) contacts ..
Please generate the next two sentences of the article | @xcite however , different models @xcite used to describe the transport through s / f interfaces yielded varying values for @xmath1 , also depending on the contact fabrication and the transport regime , @xcite an issue that is not yet understood in detail .
@xcite therefore , a key issue in pcs is to determine the pc parameters , such as the form and diameter of the metallic nanobridge and the mean free path in the immediate contact region , so that one is able to identify the relevant transport regime . usually sharvin s @xcite or wexler s @xcite formulae for the ballistic and diffusive transport regime , respectively , are used to infer the pc diameter from the measured pc resistance . |
3,091 | Suppose that you have an abstract for a scientific paper: we present theoretical results on the galactic abundance gradients of several chemical species for the milky way disk , obtained using an improved version of the two - infall model of chiappini , matteucci , & gratton ( 1997 ) that incorporates a more realistic model of the galactic halo and disk .
this improved model provides a satisfactory fit to the elemental abundance gradients as inferred from the observations and also to other radial features of our galaxy ( i.e. , gas , star formation rate and star density profiles ) .
we discuss the implications these results may have for theories of the formation of the milky way and make some predictions that could in principle be tested by future observations .
# 1_#1 _ # 1_#1 _ = # 1 1.25 in .125 in .25 in .
And you have already written the first three sentences of the full article: in this work we adopt a chemical evolution model ( see chiappini , matteucci , & romano 2000 ) that assumes two main accretion episodes for the formation of the galaxy : the first one forming the halo and bulge in a short timescale followed by a second one that forms the thin - disk , with a timescale which is an increasing function of the galactocentric distance ( being of the order of 7 gyrs at the solar neighborhood ) .
the present model takes into account in more detail than previously the halo density distribution and explores the effects of a threshold density in the star formation process , both during the halo and disk phases .
the model also includes the most recent nucleosynthesis prescriptions concerning supernovae of all types , novae and single stars dying as white dwarfs . in the comparison between model predictions and available data ,.
Please generate the next two sentences of the article | we have focused our attention on abundance gradients as well as gas , star and star formation rate distributions along the disk , since this kind of model has already proven to be quite successful in reproducing the solar neighborhood characteristics .
we suggest that the mechanism for the formation of the halo leaves heavy imprints on the chemical properties of the outer regions of the disk , whereas the evolution of the halo and the inner disk are almost completely disentangled . |
3,092 | Suppose that you have an abstract for a scientific paper: to understand the collective spiking activity in neuronal populations , it is essential to reveal basic circuit variables responsible for these emergent functional states .
here , i develop a mean field theory for the population coupling recently proposed in the studies of visual cortex of mouse and monkey , relating the individual neuron activity to the population activity , and extend the original form to the second order , relating neuron - pair s activity to the population activity , to explain the high order correlations observed in the neural data .
i test the computational framework on the salamander retinal data and the cortical spiking data of behaving rats . for the retinal data ,
the original form of population coupling and its advanced form can explain a significant fraction of two - cell correlations and three - cell correlations , respectively .
for the cortical data , the performance becomes much better , and the second order population coupling reveals non - local effects in local cortical circuits . .
And you have already written the first three sentences of the full article: to uncover the neural circuit mechanisms underlying animal behavior , e.g. , working memory or decision making , is a fundamental issue in systems neuroscience @xcite .
recent developments in multi - neuron recording methods make simultaneous recording of neuronal population activity possible , which gives rise to the challenging computational tasks of finding basic circuit variables responsible for the observed collective behavior of neural populations @xcite .
the collective behavior arises from interactions among neurons , and forms the high dimensional neural code . to search for a low dimensional and yet neurobiologically plausible representation of the neural code ,.
Please generate the next two sentences of the article | thus becomes a key step to understand how the collective states generate behavior and cognition .
correlations among neurons spiking activities play a prominent role in deciphering the neural code @xcite . |
3,093 | Suppose that you have an abstract for a scientific paper: we study the dynamics in the neighborhood of fixed points in a 4d symplectic map by means of the color and rotation method .
we compare the results with the corresponding cases encountered in galactic type potentials and we find that they are in good agreement .
the fact that the 4d phase space close to fixed points is similar to the 4d representations of the surfaces of section close to periodic orbits , indicates an archetypical 4d pattern for each kind of ( in)stability , not only in 3d autonomous hamiltonian systems with galactic type potentials but for a larger class of dynamical systems .
this pattern is successfully visualized with the method we use in the paper . .
And you have already written the first three sentences of the full article: patsis and zachilas [ 1994 ] proposed a method to visualize 4d spaces of section .
it is based on rotation of the 3d projections of the figures in order to understand the geometry of the projections and on color for understanding the distribution of the consequents in the 4th dimension .
this combined information from the rotated , colored , 3d projections allows us to associate specific structures with the dynamical behavior in the neighborhood of periodic orbits ..
Please generate the next two sentences of the article | recently the method has been applied successfully in a series of papers that studied the dynamics in the neighborhood of periodic orbits in a 3d galactic potential [ katsanikas and patsis 2011 , katsanikas et al 2011a , katsanikas et al 2011b ] .
the results of these papers , together with those of the original one by patsis and zachilas [ 1994 ] , as well as further results from work in progress , find a consistency between the shapes of the encountered structures in the 4d spaces of section and the kind of ( in)stability of the periodic orbit . despite the fact that until now no exceptional behavior has been found , the results can not be characterized as generic . |
3,094 | Suppose that you have an abstract for a scientific paper: the molecular absorption of photons with angular momentum can result in _ twisted excitons _ with a well - defined quasi - angular momentum .
although they represent different physical properties , photonic and excitonic quanta can both be described in terms of topological charge , a conserved quantity .
multiple absorption events can be used to create a wide range of excitonic topological charges .
subsequent emission produces photons that exhibit this same range . the molecule can thus be viewed as a mediator for changing the orbital angular momentum of light .
this sidesteps the need to exploit nonlinear light - matter interactions based on higher - order susceptibilities .
a tight - binding paradigm is used to establish topological charge conservation and demonstrate how it can be exploited to combine , subtract , and change the nature of the angular momentum of light .
the approach is then extended to a time - dependent density functional theory setting where the key results are shown to hold in a many - body , multi - level setting . .
And you have already written the first three sentences of the full article: beams of light can carry quantized angular momentum , @xmath0 , that are typically referred to as having a photonic topological charge ( ptc ) of @xmath1 @xcite .
circularly polarized light carries a spin angular momentum ( sam ) of @xmath2 and so has ptc of @xmath3 , but beams can also be created that twist about their axis of propagation @xcite causing them to be referred to as _ vortex beams _ or simply _ twisted light _ @xcite . at the macro - scale ,
their interaction with matter generates torque which can be used to manipulate rings of atoms @xcite and particles @xcite , carry out fabrication @xcite , provide control for spintronics @xcite , and for many other applications as well @xcite . at the atomic scale , the absorption of such photons can change the angular momentum state of bound electrons , only recently confirmed experimentally @xcite.
Please generate the next two sentences of the article | . the ptc of twisted light also amounts to an additional degree of freedom for carrying information content , and ptc values in excess of @xmath4 have been experimentally realized @xcite .
this information perspective on ptc is particularly relevant to emerging technologies in communications , computing and quantum cryptography @xcite , classical data transfer @xcite , quantum key distribution@xcite , quantum entanglement@xcite , and quantum cloning@xcite . |
3,095 | Suppose that you have an abstract for a scientific paper: we present the details and early results from a deep near - infrared survey utilising the nicmos instrument on the _ hubble space telescope _
centred around massive @xmath0 galaxies at @xmath1 found within the great observatories origins deep survey ( goods ) fields north and south .
the goods nicmos survey ( gns ) was designed to obtain deep f160w ( h - band ) imaging of 80 of these massive galaxies , as well as other colour selected objects such as lyman - break drop - outs , bzk objects , distant red galaxies ( drgs ) , extremely red objects ( eros ) , _ spitzer _ selected eros , bx / bm galaxies , as well as flux selected sub - mm galaxies .
we present in this paper details of the observations , our sample selection , as well as a description of features of the massive galaxies found within our survey fields .
this includes : photometric redshifts , rest - frame colours , and stellar masses .
we furthermore provide an analysis of the selection methods for finding massive galaxies at high redshifts , including colour selection methods and how galaxy populations selected through these colour methods overlap . we find that a single colour selection method can not locate all of the massive galaxies , with no one method finding more than 70 percent
we however find that the combination of these colour methods finds nearly all the massive galaxies , as selected by photometric redshifts with the exception of apparently rare blue massive galaxies . by investigating the rest - frame @xmath2 vs. m@xmath3 diagram for these galaxies
we furthermore show that there exists a bimodality in colour - magnitude space at @xmath4 , driven by stellar mass , such that the most massive galaxies are systematically red up to @xmath5 , while lower mass galaxies tend to be blue .
we also discuss the number densities for galaxies with stellar masses @xmath0 , whereby we find an increase of a factor of eight between @xmath6 and @xmath7 , demonstrating that this is an epoch when massive galaxies establish most of their....
And you have already written the first three sentences of the full article: our understanding of distant galaxies and the history of galaxy formation has undergone a revolution in the past decade .
galaxies are now routinely discovered and studied out to redshifts @xmath8 ( e.g. , dickinson et al .
2004 ; yan et al . 2005 ; bouwens et al ..
Please generate the next two sentences of the article | 2007 ; bouwens et al . 2010 ) . samples of a few dozen objects have been found at even higher redshift , back to the era of reionization ( @xmath9 ) , and perhaps some galaxies have been discovered at even higher redshifts , @xmath10 ( e.g. , bouwens et al . 2010 ; finkelstein et al .
this relatively rapid advance in our discovery of the earliest galaxies is the direct result of technical advances in spectroscopy and imaging over the past decade , in which the _ hubble space telescope _ ( _ hst _ ) has played a leading role . |
3,096 | Suppose that you have an abstract for a scientific paper: the universe on large scales is well described by the @xmath0cdm cosmological model .
there however remain some heavy clouds on our global understanding , especially on galaxy scales , which we review here .
while some of these clouds might perhaps disappear through small compensatory adjustments of the model , such as changing the mass of the dark matter particles or accounting better for baryonic physics , others should rather be taken as strong indications that the physics of the dark sector is , at the very least , much richer and complex than currently assumed , and that our understanding of gravity and dynamics might also be at play .
for instance , the empirically well - tested mond phenomenology in galaxies , whatever its final explanation , should be understood in any model of galaxy formation and dynamics .
current alternatives to @xmath0cdm however bring with them many unsolved questions and challenges . .
And you have already written the first three sentences of the full article: assuming general relativity to be valid on all scales , data ranging from the cosmic microwave background to individual galaxies point towards a universe dominated by dark energy and dark matter , the nature of these being most certainly amongst the deepest problems of modern physics .
while dark energy is well - represented by a cosmological constant @xmath0 in einstein s field equations , the currently preferred dark matter candidate is a collection of stable , neutral , elementary particles that condensed from the thermal bath of the early universe , and which are known as ` cold dark matter ' ( cdm ) particles ( see , e.g. , frenk & white 2012 , strigari 2012 for recent reviews ) . on galaxy scales , however , predictions of this standard @xmath0cdm cosmological model , although plagued by the enormous complications of baryonic astrophysics , are difficult to reconcile with observations .
we hereafter review these challenges for the @xmath0cdm model , and point out that some of them hint at a richer and more complex physics of the dark sector than currently assumed ..
Please generate the next two sentences of the article | in particular , many observed scaling relations involve the ubiquitous appearance of an acceleration constant @xmath1 , whose origin is a deep mystery in the standard context .
surprisingly , most of these scaling relations can be summarized by the empirical formula of milgrom ( 1983 ) . |
3,097 | Suppose that you have an abstract for a scientific paper: we discuss the supersymmetric standard model from the perspective that the up and down higgs supermultiplets are composite states .
we show that a higgs multiplet in which the scalar states are bound states of two squarks and the corresponding higgsinos are bound states of a quark and an squark has the correct supersymmetry transformations and may lead to an alternative model which displays dynamical symmetry breaking .
we describe this model through an effective higgs potential which by itself may lead to the correct mass of @xmath0 gev for the lightest higgs boson and to other neutral scalar masses respecting the experimental constraints . .
And you have already written the first three sentences of the full article: the remarkable results of the lhc experiments @xcite , @xcite culminating with the discovery of a higgs boson with a mass @xmath1 gev has limited the parameter space of many beyond the standard model theories @xcite without eliminating them completely . among the most popular candidates of this type are the supersymmetric models with their minimal version the mssm .
the fact that the supersymmetry breaking scale has been pushed further up by the experimental constraints might question if the naturalness @xcite should be one of the main driving reason for low scale supersymmetry . in this context
it would be interesting to explore other avenues supersymmetry related like that of a supersymmetric model with strong dynamics . in what follows we shall consider this point of view and sketch a possible picture in this direction ..
Please generate the next two sentences of the article | inspired by the low energy qcd and by models with dynamical symmetry breaking we shall hypothesize that the squarks of one generation ( assume the top and bottom quarks ) form bound states and condense thus leading to both electroweak and supersymmetry breaking .
the corresponding operators exist already in the mssm lagrangian but instead on dwelling on them we will consider a simple effective lagrangian which parameterizes our ignorance of the underlying strong dynamics . |
3,098 | Suppose that you have an abstract for a scientific paper: we prove a criterion for @xmath0formality of arrangements , using a complex constructed from vector spaces introduced in @xcite . as an application
, we give a simple description of @xmath0formality of graphic arrangements : let @xmath1 be a connected graph with no loops or multiple edges .
let @xmath2 be the flag ( clique ) complex of @xmath1 and let @xmath3 be the homology of the chain complex of @xmath2 .
if @xmath4 is the graphic arrangement associated to @xmath1 , we will show that @xmath4 is @xmath0formal if and only if @xmath5 for every @xmath6 .
[ section ] [ defn0]proposition [ defn0]conjecture [ defn0]theorem [ defn0]lemma [ defn0]corollary [ defn0]example partially supported by nsf dms 03 - 11142 and atp 010366 - 0103 . ] .
And you have already written the first three sentences of the full article: in @xcite , falk and randell introduced the notion of a formal arrangement .
an arrangement is formal iff every linear dependency among the defining forms of the hyperplanes can be expressed as linear combination of dependencies among exactly 3 defining forms .
many interesting classes of arrangements are formal : in @xcite , falk and randell proved that @xmath7 arrangements and arrangements with quadratic orlik - solomon ideal are formal and , in @xcite , yuzvinsky showed that free arrangements are also formal ; and gave an example showing that formality does not depend on the intersection lattice . in @xcite , brandt and terao generalized the notion of formality to @xmath0formality , proving that every free arrangement is @xmath0formal . for this they introduced the concept of higher relation spaces , which capture the dependencies among dependencies. in the first section of this paper we briefly recall the notions of relation spaces and @xmath0formality . by rewriting the definitions.
Please generate the next two sentences of the article | , we obtain a lemma characterizing @xmath0formality topologically .
then we apply this criteria for graphic arrangements to obtain a description of @xmath0formality in terms of the homology of a certain chain complex . with this |
3,099 | Suppose that you have an abstract for a scientific paper: we present the design of a detector used as a particle tracking device in the star experiment at the rhic collider of brookhaven national laboratories .
the `` stave , '' 24 of which make up the completed detector , is a highly mechanically integrated design comprised of 6 custom silicon sensors mounted on a kapton substrate .
4608 wire bonds connect these sensors to 36 analog front - end chips which are mounted on the same substrate .
power and signal connectivity from the hybrid to the front - end chips is provided by wire bonds .
the entire circuit is mounted on a carbon fiber base co - cured to the kapton substrate .
we present the unique design challenges for this detector and some novel techniques for overcoming them .
electrical and mechanical integration ; hybrid substrate ; nuclear physics ; carbon fiber reinforced polymer .
And you have already written the first three sentences of the full article: the intermediate silicon tracker ( ist ) is a silicon based particle detector installed at brookhaven national laboratory ( bnl ) in the relativistic heavy ion collider ( rhic ) .
the detector is located in the central region of the solenoidal tracker at rhic ( star ) experiment and makes up the third tracking layer in a 4-layer vertex detector upgrade .
it is comprised 24 staves , each of which is a flexible pcb wrapped around a carbon fiber core ..
Please generate the next two sentences of the article | attached to each stave are 6 silicon sensors which can detect energetic particles which pass through them .
these silicon sensors are read out by 36 analog front - end chips which are connected to an external data acquisition system . |
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