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11,500 |
Suppose that you have an abstract for a scientific paper: ( _ to appear in the cris 2006 proceedings _ ) the differential intensity of cosmic radiation shows a sequence of depressions referred to as @xmath0 in a large energy band above @xmath1 @xmath2 .
the global depression entailed in the complete spectrum with respect to the extrapolated intensity based on low energy data amounts to a maximum factor of 8 , occurring at @xmath3 @xmath2 , where flux measurements exhibit a relative minimum , referred to as the @xmath4 .
it is demonstrated by a full simulation of cosmic ray trajectories in the galaxy that the intensity minimum around the ankle energy is primarily due to the nuclear interactions of the cosmic ions with the interstellar matter and to the galactic magnetic field .
@xmath5 signal the onset energies of the rectilinear propagation in the milky way at the earth , being for example , @xmath6 @xmath2 for helium and @xmath7 @xmath2 for iron .
the ankle , in spite of its notable importance at the earth , is a local perturbation of the universal spectrum which , between the knee and the ankle , decreases by a round factor @xmath8 , regaining its unperturbed status above @xmath9 @xmath2 . .
And you have already written the first three sentences of the full article: energy measurements of giant air showers demonstrated the existence of a distinctive structure , the @xmath4 , in the differential energy spectrum of the cosmic radiation above @xmath10 .
figure 1 shows the energy spectrum measured by four experiments [ 1,2,3,4 ] at these extreme energies .
cosmic ray intensity does not continue to decrease with a spectral index between 3 and 3.2 , observed between @xmath11 and @xmath10 , but an enhancement of the intensity above @xmath3 @xmath2 appears in all experiments ..
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this enhancement is relative to the extrapolation at high energy with the index of 3 measured at lower energy , below @xmath12 @xmath2 .
the @xmath4 is the distinctive pattern in the spectrum consisting of a minimum of intensity followed by an enhancement observable approximately in the energy band @xmath3-@xmath13 .
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11,501 |
Suppose that you have an abstract for a scientific paper: we present @xmath0 photometry of palomar 6 .
our photometric measurements range from the rgb - tip to @xmath1 2 mag below the rhb and our cmds show that palomar 6 appears to have a well - defined rhb population .
the distance modulus and interstellar reddening of the cluster are estimated by comparing the magnitude and color of palomar 6 rhb stars with respect to those of 47 tuc .
we obtain @xmath2 = 14.28 mag and @xmath3 = 1.30 mag for the cluster and our study suggests that palomar 6 is clearly located in the galaxy s central regions .
we also discuss the metallicity of the cluster using the slope of the rgb .
we obtain [ fe / h ] @xmath1 @xmath41.2 for palomar 6 and our metallicity estimate is @xmath1 0.5 - 1.0 dex lower than previous estimates by others . .
And you have already written the first three sentences of the full article: palomar 6 ( @xmath5 = 17@xmath6 44@xmath7 , @xmath8 = @xmath426@xmath9 13@xmath10 ; @xmath11 = 2.1@xmath9 , @xmath12 = 1.8@xmath9 ; j2000 ) is a globular cluster @xmath1 0.8 kpc from the galactic center and @xmath1 0.2 kpc from the plane ( harris 1996 ) . since it lies near the galactic center ,
it is highly reddened .
malkan ( 1981 ) derived the interstellar reddening for palomar 6 , @xmath3 = 1.4 , based on a reddening - free metallicity index @xmath13 ..
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is defined to be h@xmath14o + 1.5 co , where h@xmath14o and co are the narrow - band infrared photometric absorption indices from h@xmath14o at 2.0 @xmath15 m and co at 2.4 @xmath15 m .
malkan ( 1981 ) claimed that there is a correlation between @xmath13 and a reddening - free ultraviolet line - blanketing parameter @xmath16 ( zinn 1980 ) with , @xmath17 ortolani , bica , & barbuy ( 1995 ) obtained @xmath3 = 1.33 @xmath18 0.10 based on the @xmath19 color magnitude diagram ( cmd ) .
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11,502 |
Suppose that you have an abstract for a scientific paper: a new numerical method is presented for solving the rotating shallow water equations on a rotating sphere using quasi - uniform polygonal meshes .
the method uses special families of finite element function spaces to mimic key mathematical properties of the continuous equations and thereby capture several desirable physical properties related to balance and conservation .
the method relies on two novel features .
the first is the use of _ compound finite elements _ to provide suitable finite element spaces on general polygonal meshes .
the second is the use of _ dual finite element spaces _ on the dual of the original mesh , along with suitably defined discrete hodge star operators to map between the primal and dual meshes , enabling the use of a finite volume scheme on the dual mesh to compute potential vorticity fluxes .
the resulting method has the same mimetic properties as a finite volume method presented previously , but is more accurate on a number of standard test cases .
compound finite element , dual finite element , mimetic , shallow water .
And you have already written the first three sentences of the full article: in order to exploit the new generation of massively parallel supercomputers that are becoming available , weather and climate models will require good parallel scalability .
this requirement has driven the development of numerical methods that do not depend on the orthogonal coordinate system and quadrilateral structure of the longitude - latitude grid , whose polar resolution clustering is predicted to lead to a scalability bottleneck .
a significant challenge is to obtain good scalability without sacrificing accuracy ; in particular conservation , balance , and wave propagation are important for accurate modelling of the atmosphere @xcite ..
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building on earlier work @xcite , @xcite presented a finite volume scheme for the shallow water equations on polygonal meshes .
they start from the continuous shallow water equations in the so - called vector invariant form : @xmath0 where @xmath1 , the geopotential , is equal to the fluid depth times the gravitational acceleration , @xmath2 is the total geopotential at the fluid s upper surface including the contribution from orography , @xmath3 is the velocity , @xmath4 is the mass flux , and @xmath5 .
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11,503 |
Suppose that you have an abstract for a scientific paper: we introduce here the concept of relative space , an extended 3-space which is recognized as the only space having an operational meaning in the study of the space geometry of a rotating disk . accordingly , we illustrate how space measurements are performed in the relative space , and we show that an old - aged puzzling problem , that is the ehrenfest s paradox , is explained in this purely relativistic context .
furthermore , we illustrate the kinematical origin of the tangential dilation which is responsible for the solution of the ehrenfest s paradox . .
And you have already written the first three sentences of the full article: in the special theory of relativity ( srt ) the rotation of the reference frame , contrary to the translation , has an absolute character and can be locally measured by the foucault s pendulum or by the sagnac experiment .
indeed , this peculiarity of rotation , inherited by newtonian physics , is difficult to understand in a relativistic context . as a matter of fact
, many authors who were contrary to srt , had found , in the relativistic approach to rotation , important arguments against the self - consistency of the theory . already in 1909.
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ehrenfest@xcite pointed out an internal contradiction in srt , applied to the case of a rotating disk ; few years later , in 1913 , sagnac@xcite,@xcite evidenced an apparent contradiction in srt with respect to the experimental data . since those years
, these seminal papers had influenced discussions on the foundations of srt , even if these `` paradoxes '' disappear when a careful analysis is undertaken , following the very axioms of the theory .
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11,504 |
Suppose that you have an abstract for a scientific paper: formation and disruption of dark - matter cusps are reviewed .
accumulation of baryons at the center of a halo can displace the dark matter , converting singular density cusps into low - density cores .
the displaced mass can be of order @xmath0 with @xmath1 the mass of the infalling population .
if @xmath1 is identified with the masses of the black holes currently observed at the centers of bright galaxies , predicted core radii are @xmath2 pc .
other mechanisms , such as early mass outflow , may explain the large dark - matter cores in dwarf and low - surface - brightness galaxies .
predictions of dark matter annihilation radiation from the center of the milky way galaxy are shown to be strongly dependent on the galaxy s merger history . .
And you have already written the first three sentences of the full article: the influential paper of navarro , frenk & white @xcite proposed a universal , broken power - law profile for dark matter halos in cold dark matter ( cdm ) cosmologies .
the dependence of @xmath3 on distance from the halo center was found to be well described by a two - parameter family of distributions , @xmath4 the central density of the nfw profile diverges as @xmath5 , similar to what was found in earlier @xmath6-body studies ( e.g. @xcite ) .
however the small - radius dependence was little more than an ansatz since the relevant scales were barely resolved in the simulations ..
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a debate ensued as to whether the profiles are indeed universal , and if so , what power of radius describes the dark matter density in the limit @xmath7 .
a number of subsequent studies @xcite found steeper central profiles , e.g. @xmath8 , the `` moore '' profile . at about the same time , the luminous ( stellar ) densities in galaxies were found to be centrally divergent @xcite ; in contrast with cdm halos , the power law index of stellar nuclei varies widely but correlates well with galaxy properties , in the sense that fainter galaxies have steeper cusps @xcite .
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11,505 |
Suppose that you have an abstract for a scientific paper: we solve einstein s constraint equations in the conformal thin - sandwich decomposition to model thin shells of non - interacting particles in circular orbit about a non - rotating black hole .
we use these simple models to explore the effects of some of the freely specifiable quantities in this decomposition on the physical content of the solutions . specifically , we adopt either maximal slicing or kerr - schild slicing , and make different choices for the value of the lapse on the black hole horizon .
for one particular choice of these quantities the resulting equations can be solved analytically ; for all others we construct numerical solutions .
we find that these different choices have no effect on our solutions when they are expressed in terms of gauge - invariant quantities . .
And you have already written the first three sentences of the full article: a 3 + 1 decomposition of einstein s equations results in a set of constraint equations , which constrain the gravitational fields at all instants of coordinate time , and a set of evolution equations , which propagate the fields forward in time ( e.g. ) .
the four constraint equations can constrain only a subset of the gravitational fields . therefore , the constraint equations can be solved , for example for the construction of initial data , only after the constrained variables have been separated from freely specifiable ones , and after suitable choices have been made for the latter ( see e.g. @xcite for reviews ) .
the constrained variables are separated from the freely specifiable ones by choosing a decomposition of the constraint equations . the conformal thin - sandwich decomposition @xcite has been particularly popular for the construction of quasiequilibrium data ; it has been used extensively , for example , to model compact binaries containing black holes or neutron stars ( see , e.g. , for reviews ) . in the conformal thin - sandwich formalism , the spatial metric is conformally decomposed into a conformal factor and the conformally related metric , and the extrinsic curvature into its trace and a traceless part . in the so - called extended version @xcite , the freely specifiable variables are the conformally related metric and the trace of the extrinsic curvature together with their time derivatives ( which we may set to zero to construct equilibrium data ) , and the constrained variables are the lapse , the shift , and the conformal factor ..
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black holes may be constructed within the conformal thin - sandwich formalism by excising the black hole interior , and imposing suitable inner boundary conditions . in particular
, these boundary conditions may be chosen so that the black hole is momentarily isolated , or in equilibrium ( see @xcite , also compare the isolated horizon formalism laid out in @xcite and references therein ) . as discussed in detail in @xcite ,
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11,506 |
Suppose that you have an abstract for a scientific paper: we give a gauge - covariant decomposition of the yang - mills field with an exceptional gauge group @xmath0 , which extends the field decomposition invented by cho , duan - ge , and faddeev - niemi for the @xmath1 yang - mills field . as an application of the decomposition
, we derive a new expression of the non - abelian stokes theorem for the wilson loop operator in an arbitrary representation of @xmath0 .
the resulting new form is used to define gauge - invariant magnetic monopoles in the @xmath0 yang - mills theory .
moreover , we obtain the quantization condition to be satisfied by the resulting magnetic charge . the method given in this paper
is general enough to be applicable to any semi - simple lie group other than @xmath1 and @xmath0 . .
And you have already written the first three sentences of the full article: understanding the mechanism underlying quark confinement from the first principle of qcd is still a challenging problem in theoretical particle physics @xcite . as a possible step towards this goal
, it will be efficient to extract the dominant field mode @xmath2 responsible for confinement from the yang - mills field @xmath3 to clarify the physics behind the phenomena of confinement .
the well - known mathematical identity called the cartan decomposition @xcite is used to decompose the field variable @xmath3 valued in the lie algebra @xmath4 of a gauge group @xmath5 into the simultaneously diagonalizable part in the cartan subalgebra @xmath6 and the remaining off - diagonal part in the orthogonal complement of @xmath7 ..
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however , the cartan decomposition is not suited for studying the non - perturbative features of the gauge field theory with local gauge invariance , since the cartan decomposition can not retain the original form after the gauge transformation , namely , the local rotation of the cartan - weyl basis for the lie algebra . in view of these , the novel decomposition called the cho - duan - ge - faddeev - niemi ( cdgfn ) decomposition @xcite is quite attractive , since the cdgfn decomposition given in the form @xmath8 is gauge covariant , namely , it keeps its form under the gauge transformation or the local color rotation . in the cdgfn decomposition
, the unit lie algebra valued field @xmath9 called the color direction field or the color field for short plays the crucial role for retaining the local gauge covariance of the decomposition . for @xmath10 , the color field @xmath11
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11,507 |
Suppose that you have an abstract for a scientific paper: nonlinear elastic effects play an important role in the dynamics of microelectromechanical systems ( mems ) .
a duffing oscillator is widely used as an archetypical model of mechanical resonators with nonlinear elastic behavior .
in contrast , nonlinear dissipation effects in micromechanical oscillators are often overlooked . in this work ,
we consider a doubly clamped micromechanical beam oscillator , which exhibits nonlinearity in both elastic and dissipative properties .
the dynamics of the oscillator is measured in both frequency and time domains and compared to theoretical predictions based on a duffing - like model with nonlinear dissipation .
we especially focus on the behavior of the system near bifurcation points .
the results show that nonlinear dissipation can have a significant impact on the dynamics of micromechanical systems . to account for the results ,
we have developed a continuous model of a geometrically nonlinear beam - string with a linear voigt - kelvin viscoelastic constitutive law , which shows a relation between linear and nonlinear damping .
however , the experimental results suggest that this model alone can not fully account for all the experimentally observed nonlinear dissipation , and that additional nonlinear dissipative processes exist in our devices . .
And you have already written the first three sentences of the full article: the field of micro - machining is forcing a profound redefinition of the nature and attributes of electronic devices .
this technology allows fabrication of a variety of on - chip fully integrated micromechanical sensors and actuators with a rapidly growing range of applications . in many cases ,
it is highly desirable to shrink the size of mechanical elements down to the nano - scale @xcite ..
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this allows enhancing the speed of operation by increasing the frequencies of mechanical resonances and improving their sensitivity as sensors .
furthermore , as devices become smaller , their power consumption decreases and the cost of mass fabrication can be significantly lowered .
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11,508 |
Suppose that you have an abstract for a scientific paper: we show that the low - energy electronic structure of arbitrarily stacked graphene multilayers with nearest - neighbor interlayer tunneling consists of chiral pseudospin doublets .
although the number of doublets in an @xmath0-layer system depends on the stacking sequence , the pseudospin chirality sum is always @xmath0 .
@xmath0-layer stacks have @xmath0 distinct landau levels at @xmath1 for each spin and valley , and quantized hall conductivity @xmath2 where @xmath3 is a non - negative integer . .
And you have already written the first three sentences of the full article: the recent explosion@xcite of research on the electronic properties of single layer and stacked multilayer graphene sheets has been driven by advances in material preparation methods@xcite , by the unusual@xcite electronic properties of these materials including unusual quantum hall effects@xcite , and by hopes that these elegantly tunable systems might be useful electronic materials . in this paper
, we demonstrate an unanticipated low - energy property of graphene multilayers , which follows from an interplay between interlayer tunneling and the chiral properties of low - energy quasiparticles in an isolated graphene sheet .
our conclusions apply in the strongest form to models with only nearest - neighbor interlayer tunneling , but are valid over a broad field range as we explain below ..
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we find that the low - energy band structure of any graphene multilayer consists of a set of independent pseudospin doublets . within each doublet ,
the bands are described by a pseudospin hamiltonian of the form @xmath4 , \label{eq : chiralband}\ ] ] where @xmath5 is a pauli matrix acting on the doublet pseudospin , @xmath6 is an envelope function momentum measured from either the @xmath7 or @xmath8 corner of the honeycomb lattice s brillouin - zone@xcite , @xmath9 , and @xmath10 is the orientation of @xmath6 .
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11,509 |
Suppose that you have an abstract for a scientific paper: we present results from observations made at 33 ghz with the very small array ( vsa ) telescope towards potential candidates in the galactic plane for spinning dust emission . in the cases of the diffuse hii regions lph96 and nrao591 we find no evidence for anomalous emission and , in combination with effelsberg data at 1.4 and 2.7 ghz , confirm that their spectra are consistent with optically thin free free emission . in the case of the infra - red bright snr 3c396 we find emission inconsistent with a purely non - thermal spectrum and discuss the possibility of this excess arising from either a spinning dust component or a shallow spectrum pwn , although we conclude that the second case is unlikely given the strong constraints available from lower frequency radio images .
radiation mechanisms : general radio continuum : ism dust , extinction ism : individual : 3c396 .
And you have already written the first three sentences of the full article: a localized excess of emission in the microwave region was first detected in the @xmath0/dmr data and was initially attributed to free free emission ( kogut et al .
1996a , 1996b ) .
since then this anomalous emission has been detected by a number of authors ( de oliveira - costa et al ..
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2002 , 2004 ; banday et al . 2003 ; finkbeiner et al . 2004 ; watson et al . 2005 ; fernndez - cerezo et al .
2006 ) , and has been nicknamed ` @xmath1 @xmath2 ' . although initially ascribed to thermal bremsstrahlung in view of its strong correlation with thermal dust , low h@xmath3 surface brightness measurements ( leitch et al .
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11,510 |
Suppose that you have an abstract for a scientific paper: we give an alternative perturbative proof of the renormalizability of the system defined by the gradient flow and the fermion flow in vector - like gauge theories . .
And you have already written the first three sentences of the full article: the non - abelian gauge theory is renormalizable in the sense that one can send the momentum cutoff infinity while keeping the strength of the interaction finite . in such a theory with an infinite cutoff , any observable
must be renormalized one and hence in gauge theory how to construct renormalized quantities is a fundamental question .
the gradient or wilson flow @xcite provides a surprisingly versatile method to define renormalized quantities in gauge theory , without explicitly referring to the perturbative renormalization ..
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see also ref .
since renormalized quantities have the meaning being independent of regularization , this method is especially useful in the context of lattice regularization with which one clearly wants to define renormalized quantities without referring to perturbation theory as much as possible . that the bare gauge field and its composite operators evolved by the gradient flow possess finite correlation functions without any wave function renormalization
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11,511 |
Suppose that you have an abstract for a scientific paper: beam stability and halo formation in high - intensity axisymmetric 2d beams in a uniform focusing channel are analyzed using particle - in - cell simulations .
the tune depression - mismatch space is explored for the uniform ( kv ) distribution of the particle transverse - phase - space density , as well as for more realistic ones ( in particular , the water - bag distribution ) , to determine the stability limits and halo parameters .
the numerical results show an agreement with predictions of the analytical model for halo formation @xcite . .
And you have already written the first three sentences of the full article: there is an increasing interest in high - current applications of ion linacs , such as the transformation of radioactive waste , the production of tritium , and fusion drivers .
high currents of the order of 100 ma restrict beam losses below 1 ppm .
thorough studies are necessary to understand mechanisms of intense - beam losses , in particular , beam instabilities and halo formation ..
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most of the theoretical efforts so far have concentrated on the kapchinsky - vladimirsky ( kv ) distribution of particles in transverse phase space @xcite .
the kv beam density is uniform so that space - charge forces inside the beam are linear .
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11,512 |
Suppose that you have an abstract for a scientific paper: we study a large class of one dimensional reaction diffusion models with quenched disorder using a real space renormalization group method ( rsrg ) which yields exact results at large time .
particles ( e.g. of several species ) undergo diffusion with random local bias ( sinai model ) and may react upon meeting .
we obtain a detailed description of the asymptotic states ( i.e attractive fixed points of the rsrg ) , such as the large time decay of the density of each specie , their associated universal amplitudes , and the spatial distribution of particles .
we also derive the spectrum of non trivial exponents which characterize the convergence towards the asymptotic states . for reactions which lead to several possible asymptotic states separated by unstable fixed points
, we analyze the dynamical phase diagram and obtain the critical exponents characterizing the transitions .
we also obtain a detailed characterization of the persistence properties for single particles as well as more complex patterns .
we compute the decay exponents for the probability of no crossing of a given point by , respectively , the single particle trajectories ( @xmath0 ) or the thermally averaged packets ( @xmath1 ) .
the generalized persistence exponents associated to @xmath2 crossings are also obtained .
specifying to the process @xmath3 or @xmath4 with probabilities @xmath5 , we compute exactly the exponents @xmath6 and @xmath7 characterizing the survival up to time @xmath8 of a domain without any merging or with mergings respectively , and the exponents @xmath9 and @xmath10 characterizing the survival up to time @xmath8 of a particle @xmath4 without any coalescence or with coalescences respectively .
@xmath1 , @xmath11 and @xmath12 obey hypergeometric equations and are numerically surprisingly close to pure system exponents ( though associated to a completely different diffusion length ) .
the effect of additional disorder in the reaction rates , as well as some open questions , are also discussed .
....
And you have already written the first three sentences of the full article: reaction diffusion processes are of wide interest in physics , chemistry and biology @xcite . in physics
they present a relatively simpler case of non equilibrium stochastic processes with non trivial behaviour .
traditionally they have been studied via mean field type methods ( e.g. law of mass action , local chemical kinetics ) @xcite . however , in sufficiently low spatial dimension , particle density fluctuations become dominant and mean field methods become invalid @xcite ..
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the role of fluctuations in these processes has thus been studied for a while , but has received renewed attention recently @xcite , as new exact results in one dimension @xcite and systematic renormalisation group studies have appeared @xcite .
one interest of these models is their relation to phase ordering kinetics via the `` coarsening '' of domain structures evolving towards equilibrium @xcite . in some cases ,
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11,513 |
Suppose that you have an abstract for a scientific paper: _ the ejecta of the first probably very massive stars polluted the big bang primordial element mix with the first heavier elements .
the resulting ultra metal - poor abundance distribution provided the initial conditions for the second stars of a wide range of initial masses reaching down to intermediate and low masses . the importance of these second stars for understanding the origin of the elements in the early universe are manifold . while the massive first stars have long vanished the second stars are still around and currently observed .
they are the carriers of the information about the first stars , but they are also capable of nuclear production themselves .
for example , in order to use ultra or extremely metal - poor stars as a probe for the r - process in the early universe a reliable model of the s - process in the second stars is needed .
eventually , the second stars may provide us with important clues on questions ranging from structure formation to how the stars actually make the elements , not only in the early but also in the present universe .
in particular the c - rich extremely metal - poor stars , most of which show the signature , are thought to be associated with chemical yields from the evolved giant phase of intermediate mass stars .
models of such agb stars at extremely low metallicity now exist , and comparison with observation show important discrepancies , for example with regard to the synthesis of nitrogen .
this may hint at burning and mixing aspects of extremely metal - poor evolved stars that are not yet included in the standard picture of evolution , as for example the hydrogen - ingestion flash .
the second stars of intermediate mass may have also played an important role in the formation of heavy elements that form through slow neutron capture reaction chains ( s - process ) .
comparison of models with observations reveal which aspects of the physics input and assumptions need to be improved .
the s - process is a particularly useful diagnostic tool....
And you have already written the first three sentences of the full article: one of the most intriguing questions of astrophysics and astronomy is the origin of the elements in the early universe , and how this relates to the first formation of structure .
about 200,000 years after the big bang the epoch of structure formation emerged and the first stars were born from the initial , pristine baryonic matter . without any elements heavier than helium to provide cooling , the first stars that formed from the baryonic matter trapped in the emerging mini - dark matter halos were probably very massive , greater than 30@xmath0 ( e.g. * ? ? ?
these massive stars burned through their available fuel in about one to two million years , exploded as supernovae , and dispersed the first elements heavier than helium into the nascent universe , or collapsed into black holes ..
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these first events of stellar evolution influenced their early universe neighborhood , and determined under which conditions and with which initial abundance low - mass stars with masses like the sun eventually formed .
these take about 100 to 1000 times longer to form than more massive stars .
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11,514 |
Suppose that you have an abstract for a scientific paper: the influence of a small perturbation on a cavity mode plays an important role in fields like optical sensing , cavity quantum electrodynamics and cavity optomechanics .
typically , the resulting cavity frequency shift directly relates to the polarizability of the perturbation .
here we demonstrate that particles perturbing a radiating cavity can induce strong frequency shifts that are opposite to , and even exceed , the effects based on the particles polarizability .
a full electrodynamic theory reveals that these anomalous results rely on a non - trivial phase relation between cavity and nanoparticle radiation , allowing back - action via the radiation continuum .
in addition , an intuitive model based on coupled mode theory is presented that relates the phenomenon to retardation .
because of the ubiquity of dissipation , we expect these findings to benefit the understanding and engineering of a wide class of systems .
the fact that a small perturbation of a potential can influence the distribution of a system s energy levels is a well - known principle permeating various branches of physics . in quantum mechanics , for example , the effect of a perturbing potential @xmath0 on an eigenstate @xmath1 is that it modifies its unperturbed energy @xmath2 by an amount @xmath3 , where @xmath4 is the new eigenstate and we assume @xmath5 . in electrodynamics ,
a local change of potential ( _ i.e. _ permittivity ) can impact the frequency of a resonant cavity .
this is at the basis of many applications that use the influence of a perturbing atom , molecule , or dielectric body to establish an interaction that can be exploited for optical sensing or control @xcite .
the shift of a mode s complex eigenfrequency @xmath6 , with cavity resonance frequency @xmath7 and linewidth @xmath8 , due to a local permittivity perturbation @xmath9 contained in a volume @xmath10 is given by @xmath11/4u_0 $ ] . here
@xmath12 and @xmath2 represent the field and total energy of the unperturbed cavity mode ,....
And you have already written the first three sentences of the full article: in this section , we show the derivation of the exact bethe - schwinger cavity perturbation formula , analogous to the approach by @xcite .
afterwards , we discuss how small approximations result in equation ( [ eq : bs ] ) of the main text .
we note , that the calculation of the different contributions to the eigenfrequency change in our simulations did not involve the approximated equation ( [ eq : bs ] ) , but the exact formula as shown in equation ( [ eq : bethe ] ) ..
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we consider the modes of an open cavity described by a spatial distribution of permittivity @xmath74 and permeability @xmath75 ( in the following , the spatial dependence of both is implicitly assumed ) .
the eigenmodes of the system are found by solving maxwell s equations in all of space in the absence of external drives .
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11,515 |
Suppose that you have an abstract for a scientific paper: we discuss the hierarchy of subphase transitions in first - order - like nucleation processes for an examplified aggregation transition of heteropolymers .
we perform an analysis of the microcanonical entropy , i.e. , the density of states is considered as the central statistical system quantity since it connects system - specific entropic and energetic information in a natural and unique way .
nucleation , first - order transition , polymer , structural phases , microcanonical analysis .
And you have already written the first three sentences of the full article: the noncovalent cooperative effects in structure formation processes on mesoscopic scales let linear polymers be very interesting objects for studies of the statistical mechanics and thermodynamics of nucleation processes , even on a fundamental level .
structural properties of polymers can typically be well described by means of simple , coarse - grained models of beads and sticks ( or springs ) representing the monomers and the covalent bonds between adjacent monomers in the chain , respectively .
contemporary , sophisticated generalized - ensemble monte carlo simulation techniques as well as large - scale computational resources enable the precise and systematic analysis of thermodynamic properties of all structural phases of coarse - grained polymer models by means of computer simulations . among the most efficient simulations methods.
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are multicanonical sampling @xcite , replica - exchange techniques @xcite , and the wang - landau method @xcite . the high precision of the numerical data for quantities that are hardly accessible in analytic calculations one of the most prominent and , as it will turn out in the following , most relevant system - specific quantities is the density ( or number ) of states with energy @xmath0 , @xmath1 opens new perspectives for the physical interpretation and classification of cooperative processes such as phase transitions .
this is particularly interesting for small systems , where conventional statistical analyses are often little systematic and a general concept seems to be missing .
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11,516 |
Suppose that you have an abstract for a scientific paper: we introduce the concept of index for regular dirichlet forms by means of energy measures , and discuss its properties . in particular , it is proved that the index of strong local regular dirichlet forms is identical with the martingale dimension of the associated diffusion processes . as an application ,
a class of self - similar fractals is taken up as an underlying space .
we prove that first - order derivatives can be defined for functions in the domain of the dirichlet forms and their total energies are represented as the square integrals of the derivatives . .
And you have already written the first three sentences of the full article: the concept of dimensions with regard to stochastic processes has been studied in various contexts . for example
, motoo and watanabe @xcite considered a class @xmath0 of martingale additive functionals of general markov processes , and proved that there exists a basis @xmath1 of @xmath0 such that every element in @xmath0 can be represented as a sum of stochastic integrals based on @xmath1 and a discontinuous part .
this is a broad extension of the study by ventcel @xcite , where the brownian motion on @xmath2 was considered ..
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the number of elements constituting the basis is sometimes called the _ martingale dimension _ , which coincides with the usual dimension of the underlying state space in typical cases .
some related arguments are found in the papers by kunita and watanabe @xcite , cramr @xcite , and so on .
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Suppose that you have an abstract for a scientific paper: giant - amplitude oscillations in dc magnetoresistance of a high - mobility two - dimensional electron system can be induced by millimeterwave irradiations , leading to zero - resistance states at the oscillation minima . following a brief overview of the now well - known phenomenon ,
this paper reports on aspects of more recent experiments on the subject .
these are : new zero - resistance states associated with multi - photon processes ; suppression of shubnikov - de haas oscillations by high - frequency microwaves ; and microwave photoconductivity of a high - mobility two - dimensional hole system . .
And you have already written the first three sentences of the full article: under irradiation of microwaves dramatic new effects occur in two - dimensional electron systems ( 2des ) in gaas - algaas heterostructures previously used to study quantum hall effects ( qhe).@xcite as first reported by zudov _
et al._,@xcite and also by ye _
et al._,@xcite in the millimeterwave ( mw ) frequency range ( @xmath0 ghz ) and in a small magnetic field ( @xmath1 t ) , at low temperatures ( @xmath2 k ) a new type of oscillations arises in the magnetoresistance @xmath3 of a high - mobility 2des ..
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these oscillations are periodic in @xmath4 and can occur in a @xmath5 weaker than the onset of shubinikov - de haas oscillations ( sdh ) .
characteristically , their period is controlled by the ratio of the microwave frequency to the electron cyclotron frequency , @xmath6 , where @xmath7 , @xmath8 is the effective mass of the conduction band electrons in gaas . in particular ,
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Suppose that you have an abstract for a scientific paper: nearly 1/3 of the sources listed in the third _ fermi _ large area telescope ( lat ) catalog ( 3fgl ) remain unassociated .
it is possible that predicted and even unanticipated gamma - ray source classes are present in these data waiting to be discovered . taking advantage of the excellent spectral capabilities achieved by the _ fermi _
lat , we use machine learning classifiers ( random forest and xgboost ) to pinpoint potentially novel source classes in the unassociated 3fgl sample outside the galactic plane . here
we report a total of 34 high - confidence galactic candidates at @xmath0 .
the currently favored standard astrophysical interpretations for these objects are pulsars or low - luminosity globular clusters hosting millisecond pulsars ( msps ) . yet , these objects could also be interpreted as dark matter annihilation taking place in ultra - faint dwarf galaxies or dark matter subhalos .
unfortunately , _ fermi _
lat spectra are not sufficient to break degeneracies between the different scenarios .
careful visual inspection of archival optical images reveals no obvious evidence for low - luminosity globular clusters or ultra - faint dwarf galaxies inside the 95% error ellipses .
if these are pulsars , this would bring the total number of msps at @xmath0 to 106 , down to an energy flux @xmath1 erg @xmath2 s@xmath3 between 100 mev and 100 gev .
we find this number to be in excellent agreement with predictions from a new population synthesis of msps that predicts 100126 high - latitude 3fgl msps depending on the choice of high - energy emission model .
if , however , these are dark matter substructures , we can place upper limits on the number of galactic subhalos surviving today and on dark matter annihilation cross sections .
these limits are beginning to approach the canonical thermal relic cross section for dark matter particle masses below @xmath4 gev in the bottom quark ( @xmath5 ) annihilation channel . .
And you have already written the first three sentences of the full article: there is compelling evidence for the existence of dark matter in the universe . already in 1933 , @xcite had collected enough data to postulate the presence of more mass than what could be inferred from visible galaxies . over the past 80 years , additional observations ranging from the rotation curves of spiral galaxies @xcite to large - scale structure @xcite seem to point in the same direction .
one outstanding prediction of cosmological simulations using cold dark matter particles is that the milky way halo should be heavily populated with thousands of smaller dark matter subhalos as a result of the hierarchical assembly process @xcite . dark matter
subhalos would include any dark matter configuration , from those hosting the largest known dwarf spheroidal galaxies in the milky way to the lightest predicted dark matter substructures with masses around @xmath6 @xcite . conceptually in this scenario , the bulk of the subhalo population is made up by small - scale dark matter substructures with limited or null star formation , which would be almost impossible to detect in existing optical surveys ..
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should dark matter subhalos without major star formation episodes exist in large numbers , one of the only ways to detect them might be by tracking gamma rays from dark matter annihilation .
the all - sky coverage and unprecedented sensitivity of the large area telescope ( lat ) , on board nasa s _ fermi _ satellite , is enabling the most effective search for potential dark matter subhalos to date .
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Suppose that you have an abstract for a scientific paper: we have studied the origin of excess noise in superconducting transition - edge sensors ( tes ) with several different detector designs .
we show that most of the observed noise and complex impedance features can be explained by a thermal model consisting of three bodies .
we suggest that one of the thermal blocks and the corresponding thermal fluctuation noise arises due to the high - frequency thermal decoupling of the normal and superconducting phase regions inside the tes film .
our results are also consistent with the prediction that in thin bilayer proximitized superconductors , the jump in heat capacity at the critical temperature is smaller than the universal bcs theory result . .
And you have already written the first three sentences of the full article: a transition - edge sensor ( tes ) is a thin superconducting film that can be used as a sensitive thermometer when voltage biased within the normal metal - superconducting transition region and read out with superconducting squid sensors @xcite .
tes based devices are used as extremely sensitive bolometers and calorimeters to detect radiation in a wide energy range from gamma - rays to sub - millimeter radiation @xcite , and typically the thermal conductance to the bath is controlled by mounting the tes on a thin insulating sin membrane .
although the performance of these detectors is already excellent , the most sensitive tes devices have not yet reached the theoretical limits in energy resolution ..
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this is mostly due to excess noise that has been shown to be present in many devices @xcite .
several candidates for the noise sources have been proposed , such as thermal fluctuations within the tes @xcite , fluctuations in the cooper - pair density @xcite or phase - slips @xcite , but a definitive answer is still missing .
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Suppose that you have an abstract for a scientific paper: we investigate the effects of matter - enhanced ( msw ) transformation of neutrinos in the early universe on the primordial helium yield ( @xmath0 ) .
we find that @xmath0 is affected much more by the msw - induced alterations in the neutrino energy spectra than by the associated change in expansion rate .
specifically , the absence due to transformation of low energy electron neutrinos can significantly affect neutron - proton weak interconversion rates through the lifting of fermi - blocking of neutron decay at low energies and through halting low - energy neutrino capture on neutrons .
we find that the change of @xmath0 within a causal horizon is @xmath1 for @xmath2 in the case of @xmath3-@xmath4-@xmath5 mixing , with the lower limit at @xmath6 , and @xmath7 for @xmath8 in the case of @xmath5-@xmath4 mixing . .
And you have already written the first three sentences of the full article: big bang nucleosynthesis ( bbn ) remains one of the most successful probes of early times in the hot big bang cosmology .
standard bbn ( sbbn ) assumes the standard model proposition of only three massless light neutrinos , leaving the primordial element abundances characterized by only one parameter , the baryon - to - photon ratio @xmath9 .
now , the evidence for neutrino mass from the super - kamiokande atmospheric neutrino observations is overwhelming @xcite ..
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in addition , the solar neutrino deficit and the lsnd experiment @xcite are hinting at the presence of a fourth light neutrino that would necessarily be `` sterile '' due to the @xmath10 decay width @xcite .
the role of neutrino masses and their mixing bring another aspect to the physical evolution of the early universe , when neutrinos played a large role .
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Suppose that you have an abstract for a scientific paper: quantum metrology promises high - precision measurements beyond the capability of any classical techniques , and has the potential to be integral to investigative techniques
. however , all sensors must tolerate imperfections if they are to be practical .
here we show that photons with perfectly overlapped modes , which are therefore fully indistinguishable , are not required for quantum - enhanced measurement , and that partially - distinguishable photons do not have to be engineered to mitigate the adverse effects of distinguishability .
we quantify the effect of distinguishability on quantum metrology experiments , and report results of an experiment to verify that two- and four - photon states containing partially - distinguishable photons can achieve quantum - enhanced sensitivity with low - visibility quantum interference .
this demonstrates that sources producing photons with mixed spectral states can be readily utilized for quantum metrology . in an ideal scenario ,
the use of non - classical states of @xmath0 photons to measure an optical phase @xmath1 will enable the scaling of precision to be increased beyond the shot - noise limit ( snl)@xmath2to the fundamental heisenberg limit@xmath3 @xcite .
however , a real sensor will operate in non - ideal conditions with non - ideal parameters .
effects such as photon loss and phase diffusion have been shown to remove much of the advantage offered by non - classical techniques , so that the snl can only be beaten by a constant factor @xcite , and this motives further study of imperfections in quantum metrology @xcite .
proposals for photonic quantum metrology typically exploit quantum interference of photons which have exactly the same parameters and are therefore perfectly indistinguishable .
achieving this indistinguishability is a major technical challenge in practice , in particular for immature and developing photon source technology .
here we study the effect on precision measurements using non - classical probe states that....
And you have already written the first three sentences of the full article: to obtain the estimates of the fisher information , for the post - selected two - photon input state as plotted in fig . 3 of the main text ,
the probability functions for each of the outcomes were first estimated . theoretically , the probability functions are : @xmath74 , \\ p\left(|\delta| = 0|\theta \right ) & = \frac{1}{4}\left [ 3 - \mathcal{i}^\prime + ( 1 + \mathcal{i}^\prime ) \cos(2 \theta ) \right ] , \end{split}\ ] ] where @xmath75
. the detection efficiency of each outcome @xmath76 will affect the observed statistics so we correct for this in order to estimate the probability functions which would be observed with ideal detection efficiency ..
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these functions are fitted to our data by allowing the fourier coefficients ; @xmath77 to vary .
we fit probability functions with positive and negative @xmath78 separately .
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Suppose that you have an abstract for a scientific paper: we carry out a global analysis of the experimental data on the @xmath0 production cross section and the ratio @xmath1 at the lhc and the tevatron . the related long - distance matrix elements ( ldmes ) at both leading order ( lo ) and next - to - leading order ( nlo ) in the qcd coupling constant are renewed .
we also present the transverse momentum distribution of the @xmath0 production cross section and the ratio @xmath1 for several experimental conditions and find that nlo predictions agree with all sets of experimental data .
by contrast , at lo , one can not explain all the data with a unique value of the color - octet ldme .
a brief analysis of the nonrelativistic qcd scale dependence of the cross sections shows that , for the conditions we are concerned with in this paper , the dependence can be almost totally absorbed into the ldme . .
And you have already written the first three sentences of the full article: since the large hadron collider ( lhc ) started its run , many experimental results have come out that have provided an opportunity to carry out further investigation of the phenomenology of qcd - based effective theories .
nonrelativistic qcd ( nrqcd ) is one of the most successful effective theories describing quarkonium production and decays @xcite . under the nrqcd framework ,
the cross section is factorized into the summation of the products of the short - distance coefficient ( sdc ) , which is independent of the quarkonium state and can be calculated perturbatively , and the long - distance matrix element ( ldme ) , which only depends on the quarkonium state and requires the fit of experimental data to extract its value ..
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the cross section for the process of heavy quarkonium @xmath2 production or decay can be expressed as d(h)=_ndf_no^h(n)[eqn : nrqcd ] where @xmath3 is the sdc for the @xmath4 state @xmath5 , and @xmath6 is the ldme of state @xmath5 for quarkonium @xmath2 .
nrqcd succeeded in many processes where the color - singlet ( cs ) model @xcite failed ; however , it still faces many challenges .
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Suppose that you have an abstract for a scientific paper: the static string - like solutions of the abelian higgs model coupled to dilaton gravity are analyzed and compared to the non - dilatonic case . except for a special coupling between the higgs lagrangian and the dilaton , the solutions are flux tubes that generate a non - asymptotically flat geometry .
any point in parameter space corresponds to two branches of solutions with two different asymptotic behaviors . unlike the non - dilatonic case , where one branch is always asymptotically conic , in the present case the asymptotic behavior changes continuously along each branch .
+ @xmath0 _ department of natural sciences , the open university of israel , _ _ p.o.b .
39328 , tel aviv 61392 , israel _
0.4 cm @xmath1 _ department of physics , university of odense , _
_ campusvej 55 , 5230 odense m , denmark _ 1.1 cm _ pacs : 11.27.+d , 04.20.jb , 98.80.cq_ .
And you have already written the first three sentences of the full article: [ secintro ] of all the topological defects @xcite , which may have been formed during phase transitions in the early universe , cosmic strings @xcite are those which have attracted most attention from a cosmological point of view .
they were introduced into cosmology some 20 years ago by kibble @xcite , zeldovich @xcite and vilenkin @xcite , and were considered for a long time as possible sources for density perturbations and hence for structure formation in the universe .
indeed , the latest data from the boomerang and maxima experiments @xcite disagree with the predictions @xcite for the cosmic microwave background anisotropies based on topological defect models ( see also ref ..
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this seems to point to the conclusion that if cosmic strings were formed in the early universe they could not have been responsible for structure formation
. however , cosmic strings are still cosmologically relevant and enjoy wide interest in cosmology . the most common field - theoretical model , which is used in order to describe the generation of cosmic strings during a phase transition , is the abelian higgs model .
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Suppose that you have an abstract for a scientific paper: we investigate matter density perturbations in models of structure formation with or without causal / acausal source . under the fluid approximation in the linear theory ,
we first derive full perturbation equations in flat space with a cosmological constant @xmath0 .
we then use green - function technique to obtain analytic solutions for matter perturbations in a flat @xmath1 model .
some incorrect solutions in the literature are corrected here . a simple yet accurate extrapolation scheme is then proposed to obtain solutions in curved or @xmath2 cosmologies .
some general features of these solutions are revealed . in particular
, we analytically prove that the resulting matter density perturbations are independent of the way the causal source was compensated into the background contents of the universe when it was first formed .
we also use our green - function solutions to investigate the compensation mechanism for perturbations with causal seeds , and yield a mathematically and physically explicit form in interpreting it .
we found that the compensation scale depends not only on the dynamics of the universe , but also on the properties of the seeds near the horizon scale .
it can be accurately located by employing our green functions .
.2 in .
And you have already written the first three sentences of the full article: the standard cosmology was lack of a mechanism to produce cosmological perturbations . in order to compensate for this flaw in the standard model , there are currently two main paradigms for structure formation inflation @xcite and topological defects @xcite . while the beauty and simplicity of the former appears to have enticed more adherents and studies , the latter has proved computationally much more challenging to make robust predictions with which to confront observations @xcite .
these two paradigms are fundamentally different in the way they generate cosmological perturbations .
the standard adiabatic inflation produces primordial perturbations on all scales of cosmological interest via quantum fluctuations and the causal constraint during inflation , and these perturbations grow over time in an uncorrelated manner . as a consequence.
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, the perturbations today can be thought of as simply transfered from the initial irregularities that inflation set up , and this transfer function can be easily obtained in the linear theory and thus well understood in the literature . on the other hand ,
topological defects are the byproducts of the spontaneous symmetry - breaking phase transition in the early universe , and hence carry energy that was carved out of the originally homogeneous background energy of the universe . therefore due to causality
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Suppose that you have an abstract for a scientific paper: we consider what occurs when we remove one of the compositeness conditions proposed by bardeen , hill and lindner that leads to predictions for the top quark mass conflicting with the experimental value . through this consideration
the condition for the higgs particle to be the composite particle is reconsidered .
we show that in this case , ( i ) the higgs - yukawa system of the standard model becomes equivalent to a non - local four - fermi system at a high - energy scale @xmath0 , ( ii ) the higgs - yukawa sector of the model becomes useless above the scale because the vacuum state can not be defined .
we regard the two phenomena as indications of the compositeness of the higgs particle .
it is suggested that the new physics above @xmath0 contains bi - local fields .
addtoresetequationsection 20.5 cm 0.2 cm nup - a-2000 - 14 + hep - ph/0007225 + eizou umezawa + .
And you have already written the first three sentences of the full article: the top quark condensation is an attractive idea that explains the electroweak symmetry breaking in the absence of fundamental scalar bosons , and gives an understanding of that the top quark mass is of the order of the electroweak scale @xcite .
bardeen , hill and lindner ( bhl ) have proposed an interesting scenario for the top condensation @xcite . in their model ,
the renormalization group ( rg ) equations play an important role , and the composite nature of the higgs particle is reflected in the boundary conditions for the coupling constants of the standard model , namely , the compositeness conditions of bhl ..
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the usual standard model is considered to well describe physical phenomena in the low energies where the higgs particle can be regarded as elementary particle . on the other hand , if the higgs particle is composed of some elementary particle , the higgs - yukawa sector of the model will be useless in some high - energy region because the lagrangian written in terms of the local higgs field must be useless to describe the inside of the higgs particle . in the scenario of bhl ,
the higgs - yukawa sector becomes useless at a high - energy scale @xmath0 and above owing to the divergence of the yukawa coupling constant for the top quark at the scale .
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Suppose that you have an abstract for a scientific paper: let @xmath0 be a closed orientable surface .
we give an explicit formula for the number mod 2 of quadruple points occurring in any generic regular homotopy between any two regularly homotopic embeddings @xmath1 .
the formula is in terms of homological data extracted from the two embeddings .
[ section ] [ thm]lemma [ thm]proposition [ thm]corollary [ thm]definition [ thm]remark .
And you have already written the first three sentences of the full article: for @xmath0 a closed surface and @xmath2 two regularly homotopic generic immersions , we are interested in the number mod 2 of quadruple points occurring in generic regular homotopies between @xmath3 and @xmath4 .
it has been shown in [ n1 ] that this number is the same for all such regular homotopies , and so it is a function of @xmath3 and @xmath4 which we denote @xmath5 . for @xmath0 orientable and @xmath1
two regularly homotopic _ embeddings _ , we give an explicit formula for @xmath6 which depends on the following data : if @xmath7 is an embedding then @xmath8 splits @xmath9 into two pieces , one compact which will be denoted @xmath10 and the other non - compact which will be denoted @xmath11 . by restriction of range.
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@xmath12 induces maps @xmath13 ( @xmath14 ) and let @xmath15 be the kernel of the map induced by @xmath16 on @xmath17 .
let @xmath18 be the orientation on @xmath0 which is induced from @xmath10 to @xmath19 and then via @xmath12 to @xmath0 .
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Suppose that you have an abstract for a scientific paper: we introduce vincular pattern posets , then we consider in particular the quasi - consecutive pattern poset , which is defined by declaring @xmath0 whenever the permutation @xmath1 contains an occurrence of the permutation @xmath2 in which all the entries are adjacent in @xmath1 except at most the first and the second .
we investigate the mbius function of the quasi - consecutive pattern poset and we completely determine it for those intervals @xmath3}}$ ] such that @xmath2 occurs precisely once in @xmath1 . .
And you have already written the first three sentences of the full article: the study of patterns in permutations is one of the most active trends of research in combinatorics .
the richness of the notion of permutation patterns is especially evident from its plentiful appearances in several very different disciplines , such as algebra , geometry , analysis , theoretical computer science , and many others .
even if it is arguably not possible to encompass all possible applications of this notion into a simple formal environment , it seems reasonable to assert that the single mathematical structure which best catches the concept of a pattern and allows us to express a great deal of results about it is the _ permutation pattern poset_. given two permutations @xmath4 , we say that @xmath5 in the permutation pattern poset whenever there is an occurrence of @xmath2 in @xmath1 as a classical pattern ..
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an extremely challenging open problem concerning the permutation pattern poset is the determination of its mbius function .
the problem , originally posed by wilf @xcite , received quite recently much attention , and some partial results have been achieved @xcite .
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Suppose that you have an abstract for a scientific paper: recent results from the lhc for the higgs boson with mass between @xmath0 points to pev - scale split supersymmetry .
this article explores the consequences of a higgs mass in this range and possible discovery modes for split susy .
moderate lifetime gluinos , with decay lengths in the to range , are its imminent smoking gun signature .
the @xmath1 lhc will be sensitive to the moderately lived gluinos and trilepton signatures from direct electroweakino production .
moreover , the dark matter abundance may be obtained from annihilation through an @xmath2-channel higgs resonance , with the lsp almost purely bino and mass @xmath3 .
the higgs resonance region of split susy has visible signatures in dark matter direct and indirect detection and electric dipole moment experiments .
if the anomalies go away , the majority of split susy parameter space will be excluded . .
And you have already written the first three sentences of the full article: the lhc has recently provided tentative evidence for a standard model higgs boson in the mass range of @xmath4 .
the hints for the higgs boson comes from several independent analyses .
first , both atlas and cms find @xmath5 excesses in the @xmath6 channel that favor the mass range of 120 to 170 gev with a production cross section equal to that of the standard model higgs with @xmath7 @xcite ..
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next , both cms and atlas observe too many @xmath8 events with three events clustered between 142 gev and 145 gev @xcite . finally , the tevatron s combined data in the @xmath9 channel is @xmath5 high with the excess consistent with the expected standard model production cross section for the higgs boson@xcite . while these excesses have not been officially combined , cms and atlas @xmath10-values are each @xmath11 and the excess could be greater than @xmath12 @xcite . and @xmath13 in split supersymmetry .
the recent experimental excess is consistent with @xmath14 , favoring scalar mass scales greater than @xmath15 .
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Suppose that you have an abstract for a scientific paper: in the light of the recent measurement of the leptonic mixing angle @xmath0 , implications of the latest mixing data have been investigated for non - minimal textures of lepton mass matrices pertaining to dirac neutrinos .
all these texture specific lepton mass matrices have been examined for their compatibility with the latest data in the cases of normal hierarchy , inverted hierarchy and degenerate scenario of neutrino masses .
the implications of all the three lepton mixing angles have been investigated on the lightest neutrino mass as well as the jarlskog s cp violating parameter in the leptonic sector . .
And you have already written the first three sentences of the full article: ever since being proposed by pauli , neutrinos have been a sort of fascinating puzzle for the physicists .
the recent observation of non zero leptonic mixing angle @xmath0 @xcite-@xcite has provided significant boost to the sharpening of implications of the neutrino oscillations and has added another dimension to neutrino physics by implying the possibility of cp violation in the leptonic sector , hence deepening the flavor puzzle further .
the non zero value of @xmath0 , on the one hand , restores the parallelism between the mixings of quarks and leptons , on the other hand , its unexpectedly ` large ' value signifies the differences between these , the leptonic mixing angles being large as compared to the quark counterparts . in the absence of any viable theory of flavor dynamics for explaining the fermion masses and mixings.
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, approaches followed on the theoretical front can broadly be catagorized into ` top - down ' and ` bottom - up ' . despite large number of attempts using the ` top - down ' perspective @xcite , we have yet to arrive at a viable approach which accounts for the vast amount of data related to flavor mixings .
therefore , in the present work , we follow the ` bottom - up ' approach consisting of finding the phenomenological fermion mass matrices which are in tune with the latest low energy data . in this context , texture
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Suppose that you have an abstract for a scientific paper: recently , a continuous dynamics was proposed to simulate dynamics of interpersonal relations in a society represented by a fully connected graph .
final state of such a society was found to be identical with the so - called heider balance ( hb ) , where the society is divided into two mutually hostile groups . in the continuous model , a polarization of opinions was found in hb .
here we demonstrate that the polarization occurs also in barabsi - albert networks , where the heider balance is not necessarily present . in the second part of this work
we demonstrate the results of our formalism , when applied to reference examples : the southern women and the zachary club . * heider balance in human networks * + p. gawroski and k. kuakowski + _ department of applied computer science , faculty of physics and applied computer science , agh university of science and technology + al .
mickiewicza 30 , pl-30059 krakw , poland _
_ pacs numbers : _ 87.23.ge _ keywords : _ numerical calculations ; sociophysics .
And you have already written the first three sentences of the full article: the heider balance @xcite is a final state of personal relations between members of a society , reached when these relations evolve according to some dynamical rules .
the relations are assumed to be symmetric , and they can be friendly or hostile . the underlying psycho - sociological mechanism of the rules is an attempt of the society members to remove a cognitive dissonance , which we feel when two of our friends hate each other or our friend likes our enemy . as a result of the process ,
the society is split into two groups , with friendly relations within the groups and hostile relations between the groups . as a special case ,.
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the size of one group is zero , i.e. all hostile relations are removed .
hb is the final state if each member interacts with each other ; in the frames of the graph theory , where the problem is formulated , the case is represented by a fully connected graph .
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Suppose that you have an abstract for a scientific paper: we study the density of states and magnetotransport properties of disordered weyl semimetals , focusing on the case of a strong long - range disorder . to calculate the disorder - averaged density of states close to nodal points , we treat exactly the long - range random potential fluctuations produced by charged impurities , while the short - range component of disorder potential is included systematically and controllably with the help of a diagram technique .
we find that for energies close to the degeneracy point , long - range potential fluctuations lead to a finite density of states . in the context of transport
, we discuss that a self - consistent theory of screening in magnetic field may conceivably lead to non - monotonic low - field magnetoresistance . .
And you have already written the first three sentences of the full article: coulomb disorder plays dominant role in determining thermodynamic and kinetic properties of doped semiconductors due to its long - range nature .
@xcite this physics becomes especially intriguing in the context of dirac materials , namely solid state systems that host quasiparticles with linear dispersion near the band - touching degeneracy points , such as that in @xmath0-wave superconductors , @xcite graphene , @xcite topological insulators @xcite and weyl semimetals .
@xcite while the former three classes of systems have been intensively studied over almost a decade by now , materials that can be identified as weyl semimetals have been discovered only fairly recently ..
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@xcite theoretical studies of the effect of disorder on a single weyl node have a long history , @xcite and this problem has been revisited in a number of recent works .
@xcite the prevailing point of view is that a weak disorder has negligible effect on the density of states , which vanishes quadraticaly with the energy counted from the nodal point .
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Suppose that you have an abstract for a scientific paper: rhythmic and sequential subdivision of the elongating vertebrate embryonic body axis into morphological somites is controlled by an oscillating multicellular genetic network termed the segmentation clock .
this clock operates in the presomitic mesoderm ( psm ) , generating dynamic stripe patterns of oscillatory gene - expression across the field of psm cells . how these spatial patterns , the clock s collective period , and the underlying cellular - level interactions are related is not understood .
a theory encompassing temporal and spatial domains of local and collective aspects of the system is essential to tackle these questions .
our delayed coupling theory achieves this by representing the psm as an array of phase oscillators , combining four key elements : a frequency profile of oscillators slowing across the psm ; coupling between neighboring oscillators ; delay in coupling ; and a moving boundary describing embryonic axis elongation .
this theory predicts that the segmentation clock s collective period depends on delayed coupling .
we derive an expression for pattern wavelength across the psm and show how this can be used to fit dynamic wildtype gene - expression patterns , revealing the quantitative values of parameters controlling spatial and temporal organization of the oscillators in the system .
our theory can be used to analyze experimental perturbations , thereby identifying roles of genes involved in segmentation . the hfsp journal , in press . .
And you have already written the first three sentences of the full article: during vertebrate development , segmentation of the continually elongating embryonic body axis occurs rhythmically and sequentially from head to tail in a process termed somitogenesis @xcite .
somites are regularly sized cell clusters that bud off periodically from the anterior end of the posterior - most unsegmented tissue , the pre - somitic mesoderm ( psm ) , with a species - specific frequency .
these transient , left - right symmetric structures are the embryonic precursors of adult bone and muscle segments , and defects in their formation lead to congenital birth defects @xcite . underlying the morphogenetic rhythm of somitogenesis , repeated waves of oscillating gene expression sweep through the cells of the psm from the posterior to the anterior @xcite , see fig ..
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[ fig : boundaries]a and supplementary movie 1 .
these genetic oscillations are thought to slow down and arrest at different phases of their cycles at an anteriorly positioned arrest front that moves in concert with embryonic elongation @xcite ( fig .
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Suppose that you have an abstract for a scientific paper: we made use of the two latest sets of rotational measures ( rms ) of extra - galactic radio sources , namely the nrao vla sky survey rotation measures catalog , and a compilation by kronberg and newton - mcgee , to infer the global structure of the galactic magnetic field ( gmf ) .
we have checked that these two data sets are mutually consistent .
given the existence of clear patterns in all - sky rm distribution we considered gmf models consisting of two components : disk ( spiral or ring ) and halo .
the parameters of these components were determined by fitting different model field geometries to the observed rms .
we found that the model consisting of a symmetric ( with respect to the galactic plane ) spiral disk and anti - symmetric halo fits the data best and reproduces the observed distribution of rms over the sky very well .
we confirm that ring disk models are disfavored .
our results favor small pitch angles around @xmath0 and an increased vertical scale of electron distribution , in agreement with some recent studies . based on our fits
, we select two benchmark models suitable for studies of cosmic ray propagation , including the ultra - high energies . .
And you have already written the first three sentences of the full article: a realistic model of the galactic magnetic field ( gmf ) is needed for various applications , such as direct dark matter searches , studies of cosmic rays , and others .
in particular , the gmf plays a crucial role in the propagation of ultra - high energy cosmic rays ( uhecrs)those with energies in excess of @xmath1 ev . their deflections ( assuming these are charged particles ) in the gmf are large enough to prevent the identification of some , perhaps most sources directly from the uhecr data .
however , in the case of protons these deflections are sufficiently small to be corrected for , provided the gmf is known with enough accuracy ..
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thus , the possibility of astronomy with charged particles at ultra - high energies may depend crucially on our knowledge of the gmf . the magnetic field ( mf ) of our galaxy
is thought to contain both regular and turbulent components ( see , e.g. , @xcite ) . while the regular component is subdominant in strength by a factor of a few , it is expected to give a dominant contribution in integral quantities such as total deflections of ultra - high energy particles . unlike the turbulent component
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Suppose that you have an abstract for a scientific paper: turing patterns can be observed in reaction - diffusion systems where chemical species have different diffusion constants . in recent years , several studies investigated the effects of noise on turing patterns and showed that the parameter regimes , for which stochastic turing patterns are observed , can be larger than the parameter regimes predicted by deterministic models , which are written in terms of partial differential equations for species concentrations . a common stochastic reaction - diffusion approach is written in terms of compartment - based ( lattice - based ) models , where the domain of interest is divided into artificial compartments and the number of molecules in each compartment is simulated . in this paper ,
the dependence of stochastic turing patterns on the compartment size is investigated .
it has previously been shown ( for relatively simpler systems ) that a modeller should not choose compartment sizes which are too small or too large , and that the optimal compartment size depends on the diffusion constant .
taking these results into account , we propose and study a compartment - based model of turing patterns where each chemical species is described using a different set of compartments .
it is shown that the parameter regions where spatial patterns form are different from the regions obtained by classical deterministic pde - based models , but they are also different from the results obtained for the stochastic reaction - diffusion models which use a single set of compartments for all chemical species . in particular , it is argued that some previously reported results on the effect of noise on turing patterns in biological systems need to be reinterpreted . .
And you have already written the first three sentences of the full article: in his pioneering work , alan turing @xcite showed that stable spatial patterns can develop in reaction - diffusion systems which include chemical species ( morphogens ) with different diffusion constants . considering a system of two chemical species with concentrations @xmath0 and @xmath1 in one - dimensional interval
@xmath2 $ ] , the underlying deterministic model of turing patterns can be written as a system of two reaction - diffusion partial differential equations ( pdes ) @xmath3 where @xmath4 and @xmath5 are diffusion constants of morphogens @xmath6 and @xmath7 , respectively , and @xmath8 and @xmath9 describe chemical reactions . then the standard analysis proceeds as follows @xcite : a homogeneous steady state @xmath10 , @xmath11 is found by solving @xmath12 and @xmath13 .
it is shown that the homogenous steady state is stable when @xmath14 , and conditions on @xmath15 , @xmath16 , @xmath4 and @xmath5 are obtained which guarantee that the homogeneous steady state will become unstable for @xmath17 . then turing patterns are observed at the steady state ..
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the above argument was extensively analysed in the mathematical biology literature and conditions for turing patterns have been determined @xcite .
experimental studies with chemical systems ( chlorite - iodide - malonic acid reaction ) demonstrated turing type patterns @xcite .
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Suppose that you have an abstract for a scientific paper: the problem of anomaly detection has been studied for a long time . in short , anomalies are abnormal or unlikely things . in financial networks ,
thieves and illegal activities are often anomalous in nature .
members of a network want to detect anomalies as soon as possible to prevent them from harming the network s community and integrity .
many machine learning techniques have been proposed to deal with this problem ; some results appear to be quite promising but there is no obvious superior method . in this paper , we consider anomaly detection particular to the bitcoin transaction network .
our goal is to detect which users and transactions are the most suspicious ; in this case , anomalous behavior is a proxy for suspicious behavior . to this end , we use three unsupervised learning methods including @xmath0-means clustering , mahalanobis distance , and unsupervised support vector machine ( svm ) on two graphs generated by the bitcoin transaction network : one graph has users as nodes , and the other has transactions as nodes . .
And you have already written the first three sentences of the full article: network structures have appeared for a long time , and along with them are those who behave abnormally within the system .
we refer to these people or their illegal activities as anomalies . with respect to financial transactional networks
, anomalies can include those who execute fraudulent transactions . in these networks ,.
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a common goal is to detect those anomalies to prevent future illegal actions .
bitcoin is a special type of transaction system ; more information about it can be found in [ 1 ] .
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Suppose that you have an abstract for a scientific paper: in this work we provide the motivation for considering non - riemannian models in cosmology .
non - riemannian extensions of general relativity theory have been studied for a long time . in such theories
the spacetime continuum is no longer described by the metric alone but endowed with additional geometric quantities .
these new quantities can be coupled to the intrinsic properties of matter in a very natural way and therefore provide a richer gravitational theory , which might be necessary in view of the recent cosmological evidence for dark matter and dark energy . in this work we mainly focus on the concepts in metric - affine gravity and point out their possible significance in the process of cosmological model building . .
And you have already written the first three sentences of the full article: cosmology , especially its observational sector , is currently a thriving field of physics . on
the theoretical side opinions have converged to what is nowadays dubbed _ cosmological concordance model _ ( ccm ) .
but , despite of all the successes of this model in describing different cosmological observations , we should not fool ourselves to believe that the grand picture of cosmology stands on a firm basis ..
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the reason for this is simple : interpretation of the data within the concordance model leads inevitably to the introduction of the concepts of _ dark matter _ and _ dark energy_. we surely could live with such concepts by stating that they depend on some peculiar details which yet have to be added to the description of our universe . unfortunately , dark matter and energy make up the complete energy budget within our simple picture and therefore can not be treated as some minor details which remains to be worked out .
this is clearly an embarrassing situation which needs to be addressed by cosmologists . in the following
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Suppose that you have an abstract for a scientific paper: after analysing the main quantum secret sharing protocol based on the entanglement states , we propose an idea to directly encode the qubit of quantum key distributions , and then present a quantum secret sharing scheme where only product states are employed . as entanglement , especially the inaccessable multi - entangled state ,
is not necessary in the present quantum secret sharing protocol , it may be more applicable when the number of the parties of secret sharing is large .
its theoretic efficiency is also doubled to approach 100% .
pacs number(s ) : 03.67.hk , 89.70.+c .
And you have already written the first three sentences of the full article: suppose the president of a bank , alice , wants to give access to a vault to two vice presidents , bob and charlie , who are not entirely trusted . instead of giving the combination to any one individual , it may be desirable to distribute information in such a way that no vice president alone has any knowledge of the combination , but both of them can jointly determine the combination .
classical cryptography provides an answer which is known as secret sharing@xcite .
alice creates two coded messages and one of them is sent to bob and the other to charlie ..
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each of the encrypted message contains no information about her original message , but together they contain the complete message .
however , either a fourth party or the dishonest member of the bob - charlie pair gains access to both of alice s transmissions can learn the contents of her message in this classical procedure .
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Suppose that you have an abstract for a scientific paper: we present an analysis of elemental abundances of ejecta of the recurrent nova rs oph using published optical and near - infrared spectra during the 2006 outburst .
we use the cloudy photoionization code to generate synthetic spectra by varying several parameters , the model generated spectra are then matched with the observed emission line spectra obtained at two epochs .
we obtain the best fit model parameters through the @xmath0 minimization technique .
our model results fit well with observed optical and near - infrared spectra .
the best - fit model parameters are compatible with a hot white dwarf source with t@xmath1 of 5.5 - 5.8 @xmath2 10@xmath3 k and roughly constant a luminosity of 6 - 8 @xmath2 10@xmath4 ergs s@xmath5 . from the analysis we find the following abundances ( by number ) of elements with respect to solar : he / h = 1.8 @xmath6 0.1 , n / h = 12.0 @xmath6 1.0 , o / h = 1.0 @xmath6 0.4 , ne / h = 1.5 @xmath6 0.1 , si / h = 0.4 @xmath6 0.1 , fe / h = 3.2 @xmath6 0.2 , ar / h = 5.1 @xmath6 0.1 , and al / h = 1.0 @xmath6 0.1 , all other elements were set at the solar abundance .
this shows the ejecta are significantly enhanced , relative to solar , in helium , nitrogen , neon , iron and argon . using the obtained parameter values , we estimate an ejected mass in the range of 3.4 - 4.9 @xmath2 10@xmath7 m@xmath8 which is consistent with observational results .
novae ; abundances . .
And you have already written the first three sentences of the full article: rs ophiuchi ( rs oph ) is a well - observed recurrent nova ( recurrence period @xmath9 20 years ) and is one of the ten confirmed recurrent novae that belong to our galaxy ( kato @xmath10 hachisu 2012 , schaefer 2010 ) .
the rs oph system is composed of a massive ( @xmath9 1.35 m@xmath8 , kato , hachisu @xmath10 luna 2008 ) white dwarf ( wd ) primary accompanied by a red giant secondary of estimated spectral class around m2 iii ( worters et al .
2007 and references therein ) ..
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brandi et al .
( 2009 ) estimated the orbital period to be 453.6 days , the red giant mass , m@xmath11 = 0.68 - 0.80 m@xmath8 and the orbital inclination , i = 49@xmath12 - 52@xmath12 for the system .
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Suppose that you have an abstract for a scientific paper: we study the dynamics resulting out of an abrupt change of the two - particle interaction in two models of closed one - dimensional fermi systems : ( a ) the field theoretical tomonaga - luttinger model and ( b ) a microscopic lattice model . using a nonperturbative approach which is controlled for small two - particle interactions we are able to reach large times allowing us to access the properties of the steady state of the lattice model . comparing those to the exact solution of the full dynamics in the tomonaga - luttinger model we provide evidence for universal luttinger liquid behavior . .
And you have already written the first three sentences of the full article: with the rapid progress in the preparation and measurement techniques for isolated cold gases @xcite investigating the fundamental questions of if and how a closed quantum many - body system prepared in a nonequilibrium initial state approaches a stationary one is within experimental reach . studying the physics of the steady state itself
is of particular interest if it is nonthermal,@xcite that is expectation values of observables differ from those computed using a canonical statistical operator with the temperature fixed by the excess energy .
one - dimensional ( 1d ) interacting fermi systems are promising candidates for realizing such unusual nonequilibrium states as in many of those the dynamics is restricted not only by energy conservation but by additional conservation laws.@xcite an often studied protocol , which we also employ , is an abrupt quench of the amplitude @xmath0 of the two - particle interaction : the system is prepared in the canonical ensemble of an initial hamiltonian @xmath1 , while the time evolution is performed with @xmath2 , @xmath3 . after taking the thermodynamic limit local observables might become stationary at long times @xmath4.@xcite in equilibrium the exactly solvable tomonaga - luttinger ( tl ) model @xcite is the infrared fixed point model under a renormalization group ( rg ) flow of a large class of interacting 1d models in their ungapped metallic phase.@xcite the low - energy physics of models out of this luttinger liquid ( ll ) universality class @xcite is given by that of the tl model . for spinless models.
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the fixed point is characterized by the velocity @xmath5 of the elementary excitations and the ll parameter @xmath6 entering exponents of algebraically decaying correlation functions .
both depend on the parameters of a given model , in particular on @xmath0 .
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Suppose that you have an abstract for a scientific paper: this work reviews and examines two particular issues related with the new technique of electrical detection of ferromagnetic resonance ( fmr ) .
this powerful technique has been broadly applied for studying magnetization and spin dynamics over the past few years .
the first issue is the relation and distinction between different mechanisms that give rise to a photovoltage via fmr in composite magnetic structures , and the second is the proper analysis of the fmr line shape , which remains the `` achilles heel '' in interpreting experimental results , especially for either studying the spin pumping effect or quantifying the spin hall angles via the electrically detected fmr . .
And you have already written the first three sentences of the full article: electrical detection of ferromagnetic resonance ( fmr ) in ferromagnets ( fm ) is a powerful new experimental tool which has transformed the research on spin and magnetization dynamics .
@xcite over the past few years , this technique has generated a great deal of interest in the communities of magnetism , spintronics , and microwave technologies .
it has been broadly applied for studying diverse material structures , ranging from ferromagnetic thin films such as py ( permalloy , ni@xmath0fe@xmath1),@xcite , cro@xmath2,@xcite fe@xmath3o@xmath4,@xcite single crystal fe,@xcite gamnas,@xcite and la@xmath5sr@xmath6mno@xmath3,@xcite bilayer devices such as py / pt,@xcite py / au,@xcite py / gaas,@xcite and y@xmath3fe@xmath7o@xmath8/pt,@xcite to a variety of magnetic tunneling junctions ( mtj ) based on magnetic multilayers.@xcite from a technical standpoint , its high sensitivity has made it possible to quantitatively determine spin boundary conditions@xcite and to directly measure non - linear magnetization damping@xcite , the quasiparticle mass for the domain wall@xcite , the phase diagram of the the spin - transfer driven dynamics@xcite and various kinds of parametric spin wave excitation @xcite . its capability to probe the interplay of spins , charges , and photons has been utilized for studying spin rectification@xcite , spin pumping@xcite , spin torque@xcite , and spin hall effects@xcite , which have led to the proposing and realization of novel dynamic spintronic devices such as the spin battery,@xcite spin diode,@xcite spin dynamo,@xcite and spin demodulator @xcite . very recently , its ability to detect coherent processes@xcite has enabled electrical probing of the spin - resonance phase and the relative phase of electromagnetic waves@xcite , which pave new ways for microwave sensing@xcite , non - destructive imaging,@xcite and dielectric spectroscopy@xcite ..
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such a coherent capability is especially exciting as it resembles the latest achievement in semiconductor spintronics , where a new platform for coherent optical control of spin / charge currents has been developed by using nonresonant quantum interferences .
@xcite from the physical standpoint , many different effects may generate a time - independent dc voltage in magnetic materials via the fmr .
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Suppose that you have an abstract for a scientific paper: let @xmath0 be an elliptic surface defined over a number field @xmath1 , where @xmath2 is a smooth projective curve , and let @xmath3 be a section defined over @xmath1 with canonical height @xmath4 . in this article , we show that the function @xmath5 on @xmath6 is the height induced from an adelically metrized line bundle with non - negative curvature on @xmath2 .
applying theorems of thuillier and yuan , we obtain the equidistribution of points @xmath7 where @xmath8 is torsion , and we give an explicit description of the limiting distribution on @xmath9 .
finally , combined with results of masser and zannier , we show there is a positive lower bound on the height @xmath10 , after excluding finitely many points @xmath11 , for any non - special " section @xmath12 of a family of abelian varieties @xmath13 that split as a product of elliptic curves . .
And you have already written the first three sentences of the full article: suppose @xmath14 is an elliptic surface defined over a number field @xmath1 , so @xmath2 is a smooth projective curve and all but finitely many fibers @xmath15 , @xmath16 , are smooth elliptic curves .
we let @xmath17 denote the nron - tate canonical height of @xmath18 viewed as an elliptic curve over the function field @xmath19 ; we let @xmath20 denote the canonical height on the fibers for ( all but finitely many ) @xmath21 .
suppose that @xmath22 is a section defined over @xmath1 for which @xmath23 , so , in particular , the points @xmath8 on the fiber are not torsion in @xmath15 for all @xmath24 ..
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tate showed that the function @xmath25 is a weil height on @xmath6 , up to a bounded error @xcite .
more precisely , there exists a divisor @xmath26 of degree equal to @xmath27 so that @xmath28 where @xmath29 is a weil height on @xmath6 associated to @xmath30 . in a series of three articles @xcite , silverman refined statement ( [ elliptic variation ] ) by analyzing the nron decomposition of the canonical height on the fibers @xmath31 where @xmath32 denotes the set of places of the number field @xmath1 , and @xmath33 are the integers appearing in the product formula @xmath34 for all @xmath35 . in this article , we explain how silverman s conclusions about the local functions @xmath36 are precisely the input needed to show that @xmath37 is a good " height function on the base curve @xmath2 , from the point of view of equidistribution . combining his work with methods from complex dynamics , as in @xcite , and the inequalities of zhang on successive minima @xcite , we prove : [ good height ] let @xmath1 be a number field and @xmath38 for a smooth projective curve @xmath2 defined over @xmath1 .
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Suppose that you have an abstract for a scientific paper: we study the propagation of quasi - discrete microwave solitons in a nonlinear left - handed coplanar waveguide coupled with split ring resonators . by considering the relevant transmission line analogue
, we derive a nonlinear lattice model which is studied analytically by means of a quasi - discrete approximation .
we derive a nonlinear schrdinger equation , and find that the system supports bright envelope soliton solutions in a relatively wide subinterval of the left - handed frequency band .
we perform systematic numerical simulations , in the framework of the nonlinear lattice model , to study the propagation properties of the quasi - discrete microwave solitons .
our numerical findings are in good agreement with the analytical predictions , and suggest that the predicted structures are quite robust and may be observed in experiments .
= 1 .
And you have already written the first three sentences of the full article: artificially engineered _ metamaterials _ have unique electromagnetic ( em ) properties , which are of great interest both from the basic physics viewpoint and for numerous applications @xcite . in such media ,
the effective permittivity @xmath0 and permeability @xmath1 is such that , in certain frequency bands , the metamaterial displays either a right - handed ( rh ) behavior ( @xmath2 , @xmath3 ) or a left - handed ( lh ) behavior ( @xmath4 , @xmath5 ) ; in other words , energy and wavefronts may travel in the same or opposite directions in the rh or the lh frequency region , respectively . metamaterials with a lh behavior , namely lh - metamaterials ( lhm ) , exhibit negative refraction at microwave @xcite or optical frequencies @xcite .
apart from the effective medium description , there has also been a large interest in studying equivalent transmission line ( tl ) models for lhms in the microwave frequency region ..
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in such a case , the effective permittivity @xmath6 and permeability @xmath1 are directly connected to the serial and shunt impedance of the tl model ; this way , so - called , _ composite right - left handed _ ( crlh ) tls @xcite may exhibit either a rh or a lh behavior depending on the frequency band . in practice , crlh - tls
may be implemented with the coplanar waveguide ( cpw ) @xcite or microstrip technology @xcite .
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Suppose that you have an abstract for a scientific paper: the problem of inter - band tunneling in a semiconductor ( zener breakdown ) in a nonstationary and homogeneous electric field is solved exactly . using the exact analytical solution ,
the approximation based on classical trajectories is studied .
a new mechanism of enhanced tunneling through static non - one - dimensional barriers is proposed in addition to well known normal tunneling solely described by a trajectory in imaginary time . under certain conditions on the barrier shape and the particle energy , the probability of enhanced tunneling
is not exponentially small even for non - transparent barriers , in contrast to the case of normal tunneling
. 1.0 cm .
And you have already written the first three sentences of the full article: a control of processes of quantum tunneling through potential barriers by external signals is a part of the field called quantum control which is actively developed now , see , for example , ref .
@xcite and references therein .
excitation of molecules , when one should excite only particular chemical bonds @xcite , formation of programmable atomic wave packets @xcite , a control of electron states in heterostructures @xcite , and a control of photocurrent in semiconductors @xcite , are typical examples of control by laser pulses ..
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a control of quantum tunneling through potential barriers is also a matter of interest , since tunneling is a part of many processes in nature .
the computation of probability for a classically forbidden region has a certain peculiarity from the mathematical stand point : there necessarily arises here the concept of motion in imaginary time or along a complex trajectory @xcite .
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Suppose that you have an abstract for a scientific paper: we show the existence of the braess paradox for a traffic network with nonlinear dynamics described by the lighthill whitham - richards model for traffic flow . furthermore
, we show how one can employ control theory to avoid the paradox .
the paper offers a general framework applicable to time - independent , uncongested flow on networks .
these ideas are illustrated through examples . .
And you have already written the first three sentences of the full article: consider the following scenario : we have a simple network consisting of two routes connecting @xmath0 to @xmath1 , see figure [ fig:4roads ] .
each route consists of two roads .
roads @xmath2 and @xmath3 are identical , as are roads @xmath4 and @xmath5 ..
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traffic is unidirectional in the direction from @xmath0 to @xmath1 .
travel time along roads @xmath2 and @xmath3 are given by @xmath6 , where @xmath7 is the number of vehicles on that road , while the travel time is @xmath8 for each of roads @xmath4 and @xmath5 , irrespective of the number of vehicles on that road . in equilibrium , vehicles will distribute evenly between the two routes connecting @xmath0 and @xmath1 , i.e. , roads @xmath2 & @xmath3 and @xmath4 & @xmath5 . assuming that initially @xmath9 vehicles start from @xmath0
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Suppose that you have an abstract for a scientific paper: an attempt has been made to extract the evolution of radial flow from the analysis of the experimental data on electromagnetic probes measured at sps and rhic energies .
the transverse momentum ( @xmath0 ) spectra of photons and dileptons measured by wa98 and na60 collaborations respectively at the cern - sps and the photon and dilepton spectra obtained by phenix collaboration at bnl - rhic have been used to constrain the theoretical models .
we use the ratio of photon to dilepton spectra to extract the flow , where some model dependence are canceled out . within the ambit of the present analysis
we argue that the variation of the radial velocity with invariant mass is indicative of a phase transition from initially produced partons to hadrons at sps and rhic energies . .
And you have already written the first three sentences of the full article: the hot and dense matter expected to be formed in the partonic phase after ultra - relativistic heavy ion collisions dynamically evolve in space and time due to high internal pressure . consequently the system cools and reverts back to hadronic matter from the partonic phase . just after the formation , the entire energy of the system is thermal in nature and with progress of time some part of the thermal energy gets converted to the collective ( flow ) energy . in other words , during the expansion stage the total energy of the system is shared by the thermal as well as the collective degrees of freedom .
the evolution of the collectivity within the system is sensitive to the equation of state ( eos ) .
therefore , the study of the collectivity in the system formed in the quark gluon plasma ( qgp ) phase will be useful to shed light on the eos @xcite ( see @xcite for review ) and on the nature of the transition that may take place during the evolution process ..
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it is well known that the average magnitude of radial flow at the freeze - out surface can be extracted from the transverse momentum ( @xmath0 ) spectra of the hadrons .
however , hadrons being strongly interacting objects can bring the information of the state of the system when it is too dilute to support collectivity _
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Suppose that you have an abstract for a scientific paper: we investigate the rigidity of hyperbolic cone metrics on @xmath0-manifolds which are isometric gluing of ideal and hyper - ideal tetrahedra in hyperbolic spaces .
these metrics will be called ideal and hyper - ideal hyperbolic polyhedral metrics .
it is shown that a hyper - ideal hyperbolic polyhedral metric is determined up to isometry by its curvature and a decorated ideal hyperbolic polyhedral metric is determined up to isometry and change of decorations by its curvature .
the main tool used in the proof is the fenchel dual of the volume function . .
And you have already written the first three sentences of the full article: we study geometry of 3-dimensional spaces which are isometric gluing of ( ideal and hyper - ideal ) tetrahedra in hyperbolic spaces .
our main focus is on the rigidity of these spaces .
the metrics of these spaces are given by the lengths of edges of tetrahedra ( in the underlying triangulation ) ..
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the curvatures of the spaces are @xmath1 less the cone angles at the edges .
our main results state that for a fixed triangulation , the curvature determines the edge lengths and hence these hyperbolic polyhedral metrics .
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Suppose that you have an abstract for a scientific paper: we present the first lyman alpha emitter ( lae ) study that combines : ( i ) cosmological sph simulations run using gadget-2 , ( ii ) radiative transfer simulations ( crash ) , and ( iii ) a previously developed lae model .
this complete lae model accounts for the intrinsic lae ly@xmath0/continuum luminosity , dust enrichment and ly@xmath0 transmission through the intergalactic medium ( igm ) , to quantify the effects of reionization , dust and velocity fields on the ly@xmath0 and uv luminosity functions ( lf ) .
we find that a model neglecting dust sorely fails to reproduce either the slope or the magnitude of the observed ly@xmath0 and uv lfs .
clumped dust is required to simultaneously fit the observed uv and ly@xmath0 lfs , such that the intrinsic ly@xmath0-to - continuum luminosity is enhanced by a factor @xmath1 ( 3.7 ) excluding ( including ) peculiar velocities .
the higher value including velocity fields arises since laes reside in large potential wells and inflows decrease their ly@xmath0 transmission . for the first time , a _
degeneracy _ is found between the the ionization state of the igm and the clumping of dust inside high - redshift galaxies .
the ly@xmath0 lf @xmath2 can be well reproduced ( to within a @xmath3 error ) by a wide range of igm average neutral hydrogen fraction , @xmath4 , provided that the increase in the ly@xmath0 transmission through a more ionized igm is compensated by a decrease in the ly@xmath0 escape fraction from the galaxy due to dust absorption .
the physical properties of laes are presented , along with a discussion of the assumptions adopted .
[ firstpage ] methods : numerical - radiative transfer - galaxies : high redshift - luminosity function - ism : dust - cosmology : theory .
And you have already written the first three sentences of the full article: the epoch of reionization marks the second major change in the ionization state of the universe .
reionization begins when the first sources of neutral hydrogen ( ) ionizing photons form within dark matter potential wells and start building an ionization region around themselves , the so - called strmgren sphere .
however , the reionization history and the redshift at which it ends still remain the subject of much discussion ..
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this is because the reionization process depends on a number of parameters including the initial mass function ( imf ) of the first sources , their star formation rates ( sfr ) , their stellar metallicity and age , the escape fraction of ionizing photons produced by each source and the clumping of the intergalactic medium ( igm ) , to name a few .
given the large number of free parameters that inevitably enter into the construction of theoretical reionization models , it is imperative to compare and update the models as fresh data sets are acquired . in this sense , it has been suggested ( malhotra & rhoads 2004 , 2005 ; santos 2004 ; mesinger , haiman & cen 2004 ; haiman & cen 2005 ; dijkstra , lidz & wyithe 2007 ; mesinger & furlanetto 2008 ; dayal , ferrara & gallerani 2008 ; dayal et al .
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Suppose that you have an abstract for a scientific paper: if @xmath0 is a set of matroids , then @xmath1 denotes the set of matroids that have no minor isomorphic to a member of @xmath0 . if @xmath2 , we say that @xmath3 is _ superfluous _
if @xmath4 contains only finitely many @xmath5-connected matroids .
we characterize the superfluous subsets of six well - known collections of excluded minors . .
And you have already written the first three sentences of the full article: if @xmath0 is a set of matroids , then let @xmath1 be the set of matroids such that @xmath6 if and only if @xmath7 has no minor isomorphic to a member of @xmath0 .
thus , if @xmath8 , then @xmath9 is the set of graphic matroids of planar graphs . hall s
classical theorem on the graphs without a @xmath10-minor @xcite can be interpreted as saying that @xmath11 contains only a single @xmath5-connected matroid , namely @xmath12 itself ..
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this motivates the following definition : if @xmath0 is a set of matroids , then @xmath2 is a _
superfluous _ subset of @xmath0 if @xmath4 contains only finitely many @xmath5-connected matroids .
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Suppose that you have an abstract for a scientific paper: metals deformed at high strain rates can exhibit failure through formation of shear bands , a phenomenon often attributed to hadamard instability and localization of the strain into an emerging coherent structure .
we verify formation of shear bands for a nonlinear model exhibiting strain softening and strain rate sensitivity .
the effects of strain softening and strain rate sensitivity are first assessed by linearized analysis , indicating that the combined effect leads to turing instability . for the nonlinear model a class of self - similar solutions
is constructed , that depicts a coherent localizing structure and the formation of a shear band .
this solution is associated to a heteroclinic orbit of a dynamical system .
the orbit is constructed numerically and yields explicit shear localizing solutions . .
And you have already written the first three sentences of the full article: shear bands are narrow zones of intense shear observed during the dynamic deformation of many metals at high strain rates .
shear localization forms a striking instance of material instability , often preceding rupture , and its study has attracted considerable attention in the mechanics _ e.g.
_ @xcite , numerical @xcite , or mathematical literature @xcite . in experimental investigations of high strain - rate deformations of steels , observations of shear bands.
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are typically associated with strain softening response past a critical strain of the measured stress - strain curve @xcite .
it was proposed by zener and hollomon @xcite , and further precised by clifton et al @xcite , that the effect of the deformation speed is twofold : an increase in the deformation speed changes the deformation conditions from isothermal to nearly adiabatic , and the combined effect of thermal softening and strain hardening of metals may produce a net softening response .
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Suppose that you have an abstract for a scientific paper: the bulk viscosity in spin - one color - superconducting strange quark matter is calculated by taking into account the interplay between the nonleptonic and semi - leptonic week processes . in agreement with previous studies
, it is found that the inclusion of the semi - leptonic processes may result in non - negligible corrections to the bulk viscosity in a narrow window of temperatures .
the effect is generally more pronounced for pulsars with longer periods .
compared to the normal phase , however , this effect due to the semi - leptonic processes is less pronounced in spin - one color superconductors . assuming that the critical temperature of the phase transition is much larger than @xmath0 , the main effect of spin - one color superconductivity in a wide range of temperatures is an overall increase of the bulk viscosity with respect to the normal phase .
the corresponding enhancement factor reaches up to about 9 in the polar and _ a_-phases , about 25 in the planar phase and about 29 in the csl phase .
this factor is determined by the suppression of the nonleptonic rate in color - superconducting matter and , therefore , may be even larger if all quark quasiparticles happen to be gapped . .
And you have already written the first three sentences of the full article: understanding the physical properties of baryonic matter above nuclear saturation density is one of the fundamental challenges in modern nuclear astrophysics .
many aspects of neutron stars ( e.g. , the mass - radius relation , cooling and rotational dynamics , glitches and pulsar kicks ) depend on these properties .
for example , the equation of state of supranuclear baryonic matter plays the key role in determining the maximum possible mass of neutron stars ..
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the harder ( softer ) equation of state is , the larger ( smaller ) maximum mass can be .
the equation of state of dense baryonic matter is also one of the essential ingredients that determines the dynamics of core - collapse supernovae and , in turn , the mass distribution of black holes in the universe @xcite .
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Suppose that you have an abstract for a scientific paper: we study isothermal magnetization processes in the cu - al - mn intermetallic alloy .
hysteresis is observed at temperatures below the spin - freezing of the system .
the characteristics of the hysteresis cycles as a function of temperature and mn content ( magnetic element ) are obtained . at low temperature
( @xmath0 k ) a change from smooth to sharp cycles is observed with increasing mn content , which is related to the decrease of configurational disorder .
we also study a zero - temperature site - diluted ising model , suitable for the description of this cu - al - mn system .
the model reproduces the main features of the hysteresis loops observed experimentally .
it exhibits a disorder - induced critical line separating a disordered phase from an incipient ferromagnetic ground - state .
the comparison between the model and the experiments allows to conclude that the observed change in the experimental hysteresis loops can be understood within the framework of the theory of disorder - induced criticality in fluctuationless first - order phase transitions . .
And you have already written the first three sentences of the full article: hysteresis is the history dependence of the properties of a material when driven by an applied external field @xcite .
it is observed in many different systems in non - equilibrium conditions . in general
it is a dynamical effect which must be treated within a time - dependent formalism . here.
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we will focus on a special class of systems that display , under certain conditions , time independent hysteresis properties .
the prototypes are ferromagnets , at low temperature , in which magnetization versus magnetic field paths are not influenced by the applied field rate , at least for low enough rates . in such materials ,
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Suppose that you have an abstract for a scientific paper: network latency and packet loss are considered to be an important requirement for realistic evaluation of peer - to - peer protocols .
dedicated clusters , such as grid5000 , do not provide the variety of network latency and packet loss rates that can be found in the internet .
however , compared to the experiments performed on testbeds such as planetlab , the experiments performed on dedicated clusters are reproducible , as the computational resources are not shared . in this paper , we perform experiments to study the impact of network latency and packet loss on the time required to download a file using bittorrent . in our experiments ,
we observe a less than 15% increase on the time required to download a file when we increase the round - trip time between any two peers , from 0 ms to 400 ms , and the packet loss rate , from 0% to 5% .
our main conclusion is that the underlying network latency and packet loss have a marginal impact on the time required to download a file using bittorrent .
hence , dedicated clusters such as grid5000 can be safely used to perform realistic and reproducible bittorrent experiments .
bittorrent , experiment , performance , clusters , latency , loss rate . .
And you have already written the first three sentences of the full article: a rich diversity in network latency and packet loss rates have become essential for experimental evaluation of bittorrent and other communication protocols used in the internet .
the need for such a diversity in network latency and packet loss rates is because of the heterogeneous nature of the internet @xcite .
the heterogeneity of the internet is the primary motivation for the creation of testbeds such as planetlab @xcite ..
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however , due to the shared nature of the planetlab platform , the results of the experiments performed on planetlab are not reproducible @xcite . in contrast , dedicated clusters , such as grid5000 @xcite , not only offer a reproducible environment but also enable the scaling of bittorrent experiments by supporting a large number of bittorrent instances on a single machine .
the primary shortcoming of experiments performed on clusters is the absence of the diverse network latency and packet loss rates that can be found in the internet . as _ the impact of the network latency and packet loss on bittorrent performance is not known _ , there exists _ a dilemma while selecting a testbed for the bittorrent experiments_. the bittorrent protocol uses tcp to efficiently distribute the _ pieces _ of a file to a large number of peers using peer - to - peer ( p2p ) connections @xcite .
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Suppose that you have an abstract for a scientific paper: the gravitational redshift measured by cottam , paerels and mendez for the neutron star ( ns ) in the low - mass x - ray binary exo 0748 - 676 depends on the identification of an absorption line during a type i burst as the h@xmath0 line from hydrogenic fe .
we show that fe is present above the photosphere as long as @xmath1 during the burst . in this limit , the total fe column is @xmath2 for incident material of solar abundances and only depends on the nuclear physics of the proton spallation .
the fe destruction creates many heavy elements with @xmath3 which may imprint photo - ionization edges on the ns spectra during a radius expansion event or in a burst cooling tail .
detecting these features in concert with those from fe would confirm a redshift measurement .
we also begin to address the radiative transfer problem , and find that a concentrated fe layer with @xmath4 and column @xmath5 ( depending on the line depth ) above the hotter continuum photosphere is required to create the h@xmath0 line of the observed strength .
this estimate must be refined by considerations of non - lte effects as well as resonant line transport . until these are carried out
, we can not say whether the fe column from accretion and spallation is in conflict with the observations .
we also show that hydrogenic fe might remain in the photosphere due to radiative levitation from the high burst flux . .
And you have already written the first three sentences of the full article: the dominant thermal flux during type i bursts and superbursts offer an ideal opportunity for studying neutron star ( ns ) properties through spectral measurements of their photospheres ( e.g. london , taam & howard 1984 , 1986 ; foster , ross & fabian 1987 ) . though never confirmed , the reports by waki et al .
( 1984 ) , turner & breedon ( 1984 ) , nakamura , inoue & tanaka ( 1988 ) and magnier et al .
( 1989 ) of 4 kev absorption lines during type i bursts motivated theoretical work on the formation of the fe ly@xmath0 line and edge ( e.g. foster et al . 1987 ; day , fabian & ross 1992 ) ..
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cottam , paerels & mendez ( 2002 ; hereafter cpm ) observed the accreting ns using the reflection grating spectrometer ( rgs ) aboard the xmm - newton satellite and claimed detection of hydrogen - like and helium - like fe absorption features from the @xmath6 h@xmath0 transitions during type i bursts .
letter _ is an initial study on the implications of the hydrogen - like feature and predictions for heavy element abundances near the photosphere .
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Suppose that you have an abstract for a scientific paper: we discuss the appearance of magnetic and charge instabilities , named respectively metamagnetism ( mm ) and phase separation ( ps ) , in systems which can be described by a perturbed luttinger liquid .
we argue that such instabilities can be associated with the vanishing of the effective fermi velocity @xmath0 , which in some cases coincides with a divergence of the effective luttinger parameter @xmath1 .
we analyze in particular an @xmath2 chain with next - nearest - neighbor interactions in different limits where mm shows up and an extended hubbard model where in turn , ps occurs .
qualitative agreement with previous studies is found .
pacs numbers : 75.10.jm , 75.60.ej # 1 # 1#1 .
And you have already written the first three sentences of the full article: the study of instabilities in low dimensional strongly correlated electron systems has received much attention in the last few years .
one of the main reasons is that a charge instability phenomenon ( phase separation ( ps ) ) often shows up in the vicinity of the superconducting transition in cuprates . in the case of double exchange models for manganese oxides that exhibit the colossal " magnetoresistance effect @xcite
, this charge instability arises close to the transition to ferromagnetism and , interestingly , finite size studies of both the two - dimensional realistic model and its one - dimensional version display similar features in this respect ..
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the case of magnetic instabilities ( metamagnetism ( mm ) ) has also received recent attention in connection to the one dimensional antiferromagnetic ( af ) @xmath2 spin chain with next - nearest - neighbor interactions ( nnn ) , where it was found that mm arises in a finite region of the phase space @xcite .
generically , at the point where charge or magnetic instabilities occur , a divergent compressibility or magnetic susceptibility arises .
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Suppose that you have an abstract for a scientific paper: the pseudo - perturbative shifted - @xmath0 expansion technique pslet is shown applicable in the non - hermitian @xmath1- symmetric context .
the construction of bound states for several @xmath2- symmetric potentials is presented , with special attention paid to @xmath3 oscillators .
[ theorem]acknowledgement [ theorem]algorithm [ theorem]axiom [ theorem]claim [ theorem]conclusion [ theorem]condition [ theorem]conjecture [ theorem]corollary [ theorem]criterion [ theorem]definition [ theorem]example [ theorem]exercise [ theorem]lemma [ theorem]notation [ theorem]problem [ theorem]proposition [ theorem]remark [ theorem]solution [ theorem]summary .
And you have already written the first three sentences of the full article: in their recent studies dorey , dunning and tateo ( ddt ) [ 1 ] have considered the manifestly non - hermitian schrdinger equation , in @xmath4 units , @xmath5 \,{\large \psi }
_ { k,\ell } ( r)=e_{k,\ell } { \large \psi } % _ { k,\ell } ( x).\ ] ] they have rigorously proved that the spectrum @xmath6 is real and discrete in the domain of the sufficiently large angular momenta , @xmath7 \equiv \ell _ { ddt}(\alpha ) .\ ] ] this inspired our subsequent study of this model [ 2 ] where we have shown that in the strong coupling regime with @xmath8 , the low lying ddt bound states may be very well approximated by the harmonic oscillators . at the same time
we have noticed that the quality of such an asymptotic approximation may deteriorate quite significantly with both the increase of excitation @xmath9 and/or with the decrease of @xmath10 ..
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such a situation is , obviously , challenging .
firstly , our study [ 2 ] revealed that the manifest non - hermiticity of the models of the type ( 1 ) leads to the reliable leading order approximation _ only after _ we select our harmonic oscillator approximant as lying _ very far _ from the real axis ( i.e. , from the hermitian regime ) .
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Suppose that you have an abstract for a scientific paper: we have observed trapping of electrons in an electrostatic trap formed over the surface of liquid @xmath0 .
these electrons are detected by a single electron transistor located at the center of the trap .
we can trap any desired number of electrons between 1 and @xmath1 . by repeatedly ( @xmath2 times ) putting a single electron into the trap and lowering the electrostatic barrier of the trap , we can measure the effective temperature of the electron and the time of its thermalisation after heating up by incoherent radiation . in 1999 ,
platzman and dykman@xcite proposed that single electrons electrostatically trapped on the surface of a liquid helium film could be used as qubits and hence form the basis of a quantum computer .
this proposal quickly aroused experimentalistsinterest.@xcite here we present experimental results on the trapping of a single ( or other desired number ) electron and measurements of the upper limit of its relaxation time in view of defining its usefulness as potential qubit . .
And you have already written the first three sentences of the full article: the tested device consists in a system of electrodes designed to hold an electron in a well - defined position over the liquid helium surface .
a single electron transistor ( set ) located below the electron is used to monitor its quantum state .
the whole structure is represented in fig.[sample ] ..
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it comprises an electron reservoir and the electron trap , which is supplied in electrons from the reservoir , and a guard electrode made out of a thick ( @xmath30.5 @xmath4 m ) layer of nb .
the structure is covered by a saturated helium film @xmath5200 - 400 in thickness .
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Suppose that you have an abstract for a scientific paper: in this paper , the isodiametric problem for centrally symmetric convex bodies in the euclidean @xmath0-space @xmath1 containing no interior non - zero point of a lattice @xmath2 is studied .
it is shown that the intersection of a suitable ball with the dirichlet - voronoi cell of @xmath3 is extremal , i.e. , it has minimum diameter among all bodies with the same volume .
it is conjectured that these sets are the only extremal bodies , which is proved for all three dimensional and several prominent lattices .
2000 mathematical subject classification : primary 52a20 , 52c07 ; secondary 52a40 keywords : isodiametric problem , lattices , dirichlet - voronoi cells , parallelohedra .
And you have already written the first three sentences of the full article: let @xmath1 be the @xmath0-dimensional euclidean space endowed with standard norm @xmath4 and inner product @xmath5 .
we denote the set of full rank lattices by @xmath6 , where a ( full rank ) _ lattice _ @xmath2 of @xmath1 is a set of the form @xmath7 with @xmath8 .
the columns of @xmath9 are called a _ basis _ of @xmath2 ..
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the determinant @xmath10 of the lattice is independent of the chosen basis . for a lattice @xmath2 ,
let @xmath11 be the family of all centrally symmetric convex bodies , that is , compact convex sets @xmath12 with @xmath13 , which do not contain a non - zero lattice point in their interior .
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Suppose that you have an abstract for a scientific paper: an experiment to demonstrate the fourier transform of an electric signal using the kundt s tube is described .
the results of finding the component frequencies and an approximation to the amplitudes of two sinusoidal signals which compose an input electric signal is presented .
undergraduate students are expected to more easily relate to the meaning of a fourier transform through such mechanical demonstrations . .
And you have already written the first three sentences of the full article: the mathematical technique of fourier transform has ubiquitous usage in physics . to demonstrate fourier transform , there are experiments available which use electronic circuits , computer programs@xcite,@xcite and bass guitar strings@xcite . in this paper
, we present a _
mechanical _ means of physically realizing a fourier transform ..
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a mechanical demonstration of a fourier transform can be achieved using a kundt s tube .
kundt s tube is a simple and an easily available apparatus in undergraduate teaching labs where it is used to measure the speed of sound . in this experiment
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Suppose that you have an abstract for a scientific paper: we present the cosmological distance errors achievable using the baryon acoustic oscillations as a standard ruler .
we begin from a fisher matrix formalism that is upgraded from @xcite .
we isolate the information from the baryonic peaks by excluding distance information from other less robust sources .
meanwhile we accommodate the lagrangian displacement distribution into the fisher matrix calculation to reflect the gradual loss of information in scale and in time due to nonlinear growth , nonlinear bias , and nonlinear redshift distortions .
we then show that we can contract the multi - dimensional fisher matrix calculations into a 2-dimensional or even 1-dimensional formalism with physically motivated approximations .
we present the resulting fitting formula for the cosmological distance errors from galaxy redshift surveys as a function of survey parameters and nonlinearity , which saves us going through the 12-dimensional fisher matrix calculations .
finally , we show excellent agreement between the distance error estimates from the revised fisher matrix and the precision on the distance scale recovered from n - body simulations . .
And you have already written the first three sentences of the full article: the famous hubble expansion drives more distant objects to recede faster from us .
recent observations of supernovae argue that this expansion is in fact accelerating , implying an existence of dark energy with negative pressure @xcite .
this dark energy , which contributes two third of energy density in the present universe , is mysterious in its physical origin ..
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precise measurements of its time evolution will be crucial to uncover the identity of this energy component .
one of most promising probes to measure the dark energy is a standard ruler called baryon acoustic oscillations in large - scale clustering @xcite baryon acoustic oscillations ( hereafter bao ) arise from sound waves that propagated in the hot plasma of tightly coupled photons and baryons in the early universe . as the universe expands and cools
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Suppose that you have an abstract for a scientific paper: with a redshift of @xmath0 , sn 1997ff is the most distant type ia supernova discovered so far .
this sn is close to several bright , @xmath1 galaxies , and we consider the effects of lensing by those objects on the magnitude of sn 1997ff .
we estimate their velocity dispersions using the tully - fisher and faber - jackson relations corrected for evolution effects , and calculate , applying the multiple - plane lensing formalism , that sn 1997ff is magnified by @xmath2 mag . due to the spatial configuration of the foreground galaxies ,
the shear from individual lenses partially cancels out , and the total distortion induced on the host galaxy is considerably smaller than that produced by a single lens having the same magnification .
after correction for lensing , the revised distance to sn 1997ff is @xmath3 mag , which improves the agreement with the @xmath4 cosmology expected from lower - redshift sne ia , and is inconsistent at the @xmath5 confidence level with a uniform gray dust model or a simple evolution model . .
And you have already written the first three sentences of the full article: one of the strongest lines of evidence for an accelerating universe is the observation that @xmath6 type ia supernovae ( sne ia ) are @xmath7 mag fainter than predicted by an @xmath8 cosmology ( riess et al .
1998 ; perlmutter et al . 1999
; riess 2000 ) ..
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however , there are several effects such as gray dust ( aguirre 1999 ) or luminosity evolution ( drell , loredo , & wasserman 2000 ) that could mimic the effect of a cosmological constant .
riess et al .
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Suppose that you have an abstract for a scientific paper: in this paper , we propose a theoretical scheme of ghost imaging in terms of @xmath0th - order correlated thermal light .
we obtain the gaussian thin lens equations in the ghost imaging protocol .
we show that it is possible to produce @xmath1 ghost images of an object at different places in a nonlocal fashion by means of a higher - order correlated imaging process with an @xmath0th - order correlated thermal source and correlation measurement .
we investigate the visibility of the ghost images in the scheme , and obtain the upper bounds of the visibility for the @xmath0th - order correlated thermal - light ghost imaging .
it is found that the visibility of the ghost images can be dramatically enhanced when the order of correlation becomes larger . .
And you have already written the first three sentences of the full article: ghost imaging with thermal light @xcite has been studied extensively in recent years .
bennink and coworkers @xcite first pointed out that ghost imaging can also be realized using a classical source with the appropriate correlations .
a thermal or quasi - thermal source can exhibit such a classical correlation ..
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a very close formal analogy was demonstrated between ghost imaging with thermal and quantum - entangled beams in refs .
@xcite , which implied that classically correlated beams were able to emulate the relevant features of quantum ghost imaging .
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Suppose that you have an abstract for a scientific paper: we present the optical spectra of four newly discovered gravitational lenses from the cosmic lens all - sky survey ( class ) .
these observations were carried out using the low resolution imaging spectrograph on the w. m. keck - i telescope as part of a program to study galaxy - scale gravitational lenses . from our spectra
we found the redshift of the background source in class b0128 + 437 ( @xmath0 ) and the lensing galaxy redshifts in class b0445 + 123 ( @xmath1 ) and class b0850 + 054 ( @xmath2 ) .
intriguingly , we also discovered that class b0631 + 519 may have two lensing galaxies ( @xmath3 , @xmath4 ) .
we also found a single unidentified emission line from the lensing galaxy in class b0128 + 437 and the lensed source in class b0850 + 054 .
we find the lensing galaxies in class b0445 + 123 and class b0631 + 519 ( @xmath5 ) to be early - type galaxies with einstein radii of @xmath6 kpc .
the deflector in class b0850 + 054 is a late - type galaxy with an einstein radius of @xmath7 kpc .
[ firstpage ] gravitational lensing - quasars : individual : class b0128 + 437 , class b0445 + 123 , class b0631 + 519 , class b0850 + 054 .
And you have already written the first three sentences of the full article: gravitational lensing has the ability to probe the internal mass distributions of galaxies at cosmological distances .
the ability to form complete samples , based solely on mass , has allowed studies of the formation and evolution of early - type galaxies at intermediate redshifts ( e.g. @xcite ; @xcite ) .
anomalous flux - density ratios observed in merging gravitational lens images have recently been used to argue for cold dark matter substructure within the haloes of lensing galaxies @xcite ..
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the magnification of the lensed source has also allowed studies of star - formation at high redshift ( e.g. @xcite ) and the dust content of quasar host galaxies to be estimated @xcite .
furthermore , gravitational lenses have proved to be powerful tools for determining the cosmological parameters .
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Suppose that you have an abstract for a scientific paper: following an early claim by nelson & mcevoy @xcite suggesting that word associations can display ` spooky action at a distance behaviour ' , a serious investigation of the potentially quantum nature of such associations is currently underway .
this paper presents a simple quantum model of a word association system .
it is shown that a quantum model of word entanglement can recover aspects of both the spreading activation model and the spooky model of word association experiments . .
And you have already written the first three sentences of the full article: human beings are adept and drawing context - sensitive associations and inferences across a broad range of situations ranging from the mundane to the creative inferences that lead to scientific discovery .
such reasoning has a strong pragmatic character and is transacted with comparatively scarce cognitive assets . however , despite our apparent proficiency at drawing inferences , and our ability to express words in such a manner that other people can ( usually ) understand the meaning that we are trying to convey , our theoretical understanding of how this process occurs has been slow to develop .
the field of cognitive science has recently produced an ensemble of semantic models which have an encouraging , and at times impressive track record of replicating human information processing , such as human word associations norms @xcite ..
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the term `` semantic '' derives from the intuition that words seen in the context of a given word contribute to its meaning , or , more colloquially expressed , the meaning of a word is derived from the `` company it keeps '' @xcite . in order to progress in our understanding of how meaning is generated from sets of words in a language we must understand the way in which the mental lexicon of that language is generated during language acquisition , and how it works once created in the mind of a specific individual .
the mental lexicon of a language refers to the words of a language , but its structure is represented by the associative links that bind this vocabulary together .
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Suppose that you have an abstract for a scientific paper: we present a perspective on quantum games that focuses on the physical aspects of the quantities that are used to implement a game . if a game is to be played , it has to be played with objects and actions that have some physical existence .
we call such games playable . by focusing on the notion of playability for games we can more clearly see the distinction between classical and quantum games and tackle the thorny issue of what it means to quantize a game .
the approach we take can more properly be thought of as gaming the quantum rather than quantizing a game and we find that in this perspective we can think of a complete quantum game , for a given set of preferences , as representing a single family of quantum games with many different playable versions .
the versions of quantum prisoners dilemma presented in the literature can therefore be thought of specific instances of the single family of quantum prisoner s dilemma with respect to a particular measurement .
the conditions for equilibrium are given for playable quantum games both in terms of expected outcomes and a geometric approach .
we discuss how any quantum game can be simulated with a classical game played with classical coins as far as the strategy selections and expected outcomes are concerned . .
And you have already written the first three sentences of the full article: multiplayer non - cooperative game theory is a mathematical formulation of competition in which players compete against one another to obtain some resource or reward [ 1 ] . at its most abstract level
a game is simply a mapping , via some function , of the elements of one set to another .
although the mathematics of game theory can be phrased in terms of such abstract symbols , those symbols are given an interpretation in terms of the actions , or strategies , of the players and the eventual rewards they receive ..
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implicit in this interpretation is the notion that , should it be so desired , the players could actually _ play _ such a game .
in other words , there exists a real physical implementation of a game in terms of physically realizable actions and tangible rewards .
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Suppose that you have an abstract for a scientific paper: we present a formalism for computing the complexity of metastable states and the zero - temperature magnetic hysteresis loop in the soft - spin random - field model in finite dimensions .
the complexity is obtained as the legendre transform of the free - energy associated to a certain action in replica space and the hysteresis loop above the critical disorder is defined as the curve in the field - magnetization plane where the complexity vanishes ; the nonequilibrium magnetization is therefore obtained without having to follow the dynamical evolution .
we use approximations borrowed from condensed - matter theory and based on assumptions on the structure of the direct correlation functions ( or proper vertices ) , such as a local approximation for the self - energies , to calculate the hysteresis loop in three dimensions , the correlation functions along the loop , and the second moment of the avalanche - size distribution . .
And you have already written the first three sentences of the full article: the random - field ising model ( rfim ) at zero temperature is a prototype of many disordered systems which exhibit hysteretic and jerky behavior when an external parameter ( _ e.g. _ magnetic field , pressure , strain ) is slowly changed@xcite .
this behavior is related to the existence of a corrugated ( free ) energy landscape with many local minima ( or metastable states ) separated by barriers much larger than @xmath0 , therefore preventing relaxation towards equilibrium on experimental time scales . as a consequence ,
the response to an external driving field is a series of discontinuous jumps ( called avalanches ) from one metastable state to another , the number and size of these jumps varying with the amount of disorder . in the 3-dimensional rfim with gaussian random fields two regimes of avalanches.
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are observed@xcite : at large disorder , there are many microscopic jumps resulting in a smooth magnetization curve macroscopically ; at low disorder , there is a system - spanning avalanche resulting in a macroscopic jump in the magnetization curve .
these two regimes are separated by a critical point at which avalanches of all sizes are observed . as shown recently
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Suppose that you have an abstract for a scientific paper: the relation between event horizons and trapping horizons is investigated in a number of different situations with emphasis on their role in thermodynamics . a notion of constant change
is introduced that in certain situations allows the location of the event horizon to be found locally .
when the black hole is accreting matter the difference in area between the two different horizons can be many orders of magnitude larger than the planck area .
when the black hole is evaporating the difference is small on the planck scale .
a model is introduced that shows how trapping horizons can be expected to appear outside the event horizon before the black hole starts to evaporate .
finally a modified definition is introduced to invariantly define the location of the trapping horizon under a conformal transformation . in this case
the trapping horizon is not always a marginally outer trapped surface . .
And you have already written the first three sentences of the full article: black holes are defined by their horizons .
there are different types of black hole horizons that can be used in different situations .
what type of horizon is relevant may depend on the question being asked . in black hole thermodynamics.
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the area of the black hole plays a role analogous to entropy via the bekenstein - hawking relation .
there has been a rigorous attempt to understand whether this entropy has an underlying microscopic explanation and it is hoped that the answer to this question will be an important clue to a theory of quantum gravity .
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Suppose that you have an abstract for a scientific paper: the color - magnitude relation ( cmr ) of early - type galaxies in clusters provides a powerful tool for finding clusters and determining photometric redshifts for clusters using two - filter imaging data .
we demonstrate the high accuracy of photometric redshifts attainable using the cmr by applying the technique to a sample of 45 abell clusters with known redshifts .
furthermore , by using the red sequence of galaxies from the cmr , we have developed an extremely efficient technique for detecting clusters and groups of galaxies .
we demonstrate this using both observed photometric catalogs with redshifts ( from the cnoc2 survey ) and simulations . .
And you have already written the first three sentences of the full article: early - type galaxies form the dominant population in the core of all galaxy clusters with few or no exceptions from low redshift to @xmath0 , from poor to rich clusters .
the uniformity of the properties of early - type galaxies provide important tools , such as the fundamental plane and the color - magnitude relation ( cmr ) , in the study of galaxy clusters and their evolution .
the cmr for early - type galaxies ( e / s0 s ) was first noted by baum ( 1959 ) in that the colors for elliptical galaxies become bluer as they become less luminous ..
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furthermore , e / s0 galaxies are also the reddest normal galaxies at any single given redshift .
hence , the e / s0 s form a sequence on the color - magnitude plane which is sometimes called the `` red sequence '' , as illustrated for the cluster abell 2256 using data from lpez - cruz & yee ( 1999a , also see lpez - cruz 1997 ) in figure 1 .
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Suppose that you have an abstract for a scientific paper: we study the three nucleon force in @xmath0 dynamical clover fermion lattice qcd , utilizing the nambu - bethe - salpeter wave function of the three nucleon system .
since parity - odd two nucleon potentials are not available in lattice qcd at this moment , we develop a new formulation to extract the genuine three nucleon force which requires only the information of parity - even two nucleon potentials . in order to handle the extremely expensive calculation cost
, we consider a specific three - dimensional coordinate configuration for the three nucleons .
we find that the linear setup is advantageous , where nucleons are aligned linearly with equal spacings .
the lattice calculation is performed with @xmath1 configurations at @xmath2 , @xmath3gev generated by cp - pacs collaboration , and the result of the three nucleon force in triton channel is presented .
address= graduate school of pure and applied sciences , university of tsukuba , tsukuba 305 - 8571 , japan .
And you have already written the first three sentences of the full article: understanding the interaction among nucleons is one of the most important issues in particle and nuclear physics .
in particular , the properties of the three nucleon force ( tnf ) are the forefront of not only particle / nuclear physics but also astro physics . for the binding energies of light nuclei , the two nucleon ( 2n ) force alone underestimates the experimental data , and attractive tnf components are required @xcite . on the other hand , repulsive tnf components are also necessary in both of symmetric and asymmetric nuclear matters , in order to reproduce the empirical saturation density of nuclei in the former case , and to make the equation of state of asymmetric nuclear matter hard enough to sustain the observed massive neutron star masses in the latter case @xcite .
recently , it is argued that tnf is responsible for the anomaly in the drip line and the nontrivial magic number of neutron - rich nuclei @xcite , and could impact on the supernova nucleosynthesis ..
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pioneered by fujita - miyazawa @xcite , tnf have been commonly studied from the two - pion exchange models with the @xmath4-excitation . however , since tnf is originated by the fact that a nucleon is not a fundamental particle , it is desirable to study tnf from the fundamental degrees of freedom ( dof ) , i.e. , quarks and gluons . in this report , we carry out first - principle calculations of tnf using the lattice qcd technique . in the lattice qcd calculation of nuclear forces , it is recently proposed @xcite to use the nambu - bethe - salpeter ( nbs ) wave function so that the potential is faithful to the phase shift by construction .
the obtained ( parity - even ) 2n potentials are found to have desirable features , such as attractive well at long and medium distances , and the central repulsive core at short distance @xcite .
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Suppose that you have an abstract for a scientific paper: excitable media are a generic class of models used to simulate a wide variety of natural systems including cardiac tissue .
propagation of excitation waves in this medium results in the formation of characteristic patterns such as rotating spiral waves .
instabilities in these structures may lead to spatiotemporal chaos through spiral turbulence , which has been linked to clinically diagnosed conditions such as cardiac fibrillation .
usual methods for controlling such phenomena involve very large amplitude perturbations and have several drawbacks .
there have been several recent attempts to develop low - amplitude control procedures for spatiotemporal chaos in excitable media which are reviewed in this paper .
the control schemes have been broadly classified by us into three types : ( i ) global , ( ii ) non - global spatially - extended and ( iii ) local , depending on the way the control signal is applied , and we discuss the merits and drawbacks for each . .
And you have already written the first three sentences of the full article: excitable media denotes a class of systems that share a set of features which make their dynamical behavior qualitatively similar .
these features include ( i ) the existence of two characteristic dynamical states , comprising a stable _ resting state _ and a metastable _ excited state _ , ( ii ) a _ threshold _ value associated with one of the dynamical variables characterising the system , on exceeding which , the system switches from the resting state to the excited state , and ( iii ) a _ recovery period _ following an excitation , during which the response of the system to a supra - threshold stimulus is diminished , if not completely absent @xcite .
natural systems which exhibit such features include , in biology , cells such as neurons , cardiac myocytes and pancreatic beta cells , all of which are vital to the function of a complex living organism ..
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other examples of dynamical phenomena associated with excitable media include camp waves observed during aggregation of slime mold , calcium waves observed in xenopus oocytes , muscle contractions during childbirth in uterine tissue , chemical waves observed in the belusov - zhabotinsky reaction and concentration patterns in co - oxidation reaction on pt(110 ) surface .
excitation in such systems is observed as the characteristic _ action potential _ , where a variable associated with the system ( e.g. , membrane potential , in the case of biological cells ) increases very fast from its resting value to the peak value corresponding to the excited state , followed by a slower process during which it gradually returns to the resting state .
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Suppose that you have an abstract for a scientific paper: a galaxy system must have a minimum velocity dispersion for its mass to be greater than the sum of the masses of its galaxies .
nearly half of the nearby hickson compact groups ( hcgs ) have too low a velocity dispersion in comparison with the rotational velocities of their spiral galaxies and internal velocity dispersions of their early types . a detailed study of the low velocity dispersion group , hcg 16 the only known group of late - type galaxies with diffuse intergalactic x - ray emitting hot gas
reveals that half of the diffuse x rays are associated with foreground / background sources and the remaining gas is clumpy and mostly associated with the bright galaxies of the group .
the large - scale environment of the group suggests that hcg 16 lies where a cosmological filament falls perpendicularly onto a large - scale sheet .
the observed frequency of compact groups is lower than predicted from the extended press - schechter formalism , which also predicts that most @xmath0 objects in the universe must be fairly old and hence have already coalesced into single objects , reminiscent of elliptical galaxies over - luminous in x - rays that are now being discovered .
thus , the low survival time of dense groups against the merging instability is no longer a worry for compact groups , as they form in large enough numbers .
i show why other arguments against the reality of hcgs no longer hold , partly because of the biases of hickson s sample .
-2 cm _ contribution to iau colloq .
174 on small galaxy groups , held in turku , finland , june 1318 , 1999 , ed .
m. valtonen & c. flynn , asp series _ .
And you have already written the first three sentences of the full article: compact groups ( hereafter cgs ) have been puzzling astronomers for a number of years . how can a few bright galaxies coexist within less than 100 kpc ?
cgs may have formed early , and have managed to survive the merging instability ( @xcite ; athanassoula , in these proceedings ) or else formed just recently @xcite . alternatively
, cgs may be not be truly dense in 3d , but caused instead by chance alignments of galaxies along the line of sight within larger loose groups @xcite , clusters @xcite and cosmological filaments ( @xcite , hereafter hkw ) . in this contribution.
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, we provide new light on this debate by studying the group velocity dispersions , x - ray , optical and continuum radio emission , and by predicting the frequency of dense groups as compact as @xcite s ( @xcite , hereafter hcgs ) appear to be , using the @xcite cosmological formalism .
we conclude on the nature of hcgs .
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Suppose that you have an abstract for a scientific paper: .7em garoufalidis and levine introduced the homology cobordism group of homology cylinders over a surface .
this group can be regarded as an enlargement of the mapping class group .
using torsion invariants , we show that the abelianization of this group is infinitely generated provided that the first betti number of the surface is positive .
in particular , this shows that the group is not perfect .
this answers questions of garoufalidis - levine and goda - sakasai .
furthermore we show that the abelianization of the group has infinite rank for the case that the surface has more than one boundary component .
these results hold for the homology cylinder analogue of the torelli group as well
. subjclassname@1991=subjclassname@2000= .
And you have already written the first three sentences of the full article: given @xmath0 and @xmath1 , let @xmath2 be a fixed oriented , connected and compact surface of genus @xmath3 with @xmath4 boundary components .
we denote by @xmath5 the group of orientation preserving diffeomorphisms of @xmath2 which restrict to the identity on the boundary . the _ mapping class group _
@xmath6 is defined to be the set of isotopy classes of elements in @xmath7 , where the isotopies are understood to restrict to the identity on the boundary as well ..
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we refer to ( * ? ? ?
* section 2.1 ) for details .
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Suppose that you have an abstract for a scientific paper: the present manuscript considers the application of the method of the near - edge x - ray absorption spectroscopy ( nexafs ) for the investigation of the graphene - based systems ( from free - standing graphene to the metal - intercalation - like systems ) .
the spectra for the selected systems are calculated in the framework of the approach , which includes the effects of the dynamic core - hole screening .
the presented spectral changes from system to system are analysed with the help of the corresponding band - structure calculations .
the obtained results are compared with available experimental data demonstrating the excellent agreement between theory and experiment .
the direct correlation between the strength of the graphene interaction with the metallic substrate and the spectral distributions ( shape and intensities of @xmath0 and @xmath1 features in the c @xmath2 nexafs spectra ) is found that can be taken as a fingerprint for the description of interaction at the graphene / metal interface .
nexafs / xes / xmcd project : .
And you have already written the first three sentences of the full article: the method of x - ray absorption spectroscopy ( xas ) is one of the widely used spectroscopic tools for electronic structure investigations in condensed matter physics @xcite .
it is based on the absorption of the x - ray photons when core shell electron is transferred into the unoccupied valence band states ( conduction band ) above the fermi level ( @xmath3 ) ( fig .
[ fig : scheme ] ) ..
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therefore one or more jumps ( absorption edges ) are usually observed in the absorption spectrum .
moreover the energy position of any edge is element specific since it coincides with the energy of the corresponding atomic core level . besides
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Suppose that you have an abstract for a scientific paper: we provide a thorough exposition of recent results on the quantum stabilization of cosmic strings .
stabilization occurs through the coupling to a heavy fermion doublet in a reduced version of the standard model .
the study combines the vacuum polarization energy of fermion zero - point fluctuations and the binding energy of occupied energy levels , which are of the same order in a semi - classical expansion . populating these bound states
assigns a charge to the string .
strings carrying fermion charge become stable if the higgs and gauge fields are coupled to a fermion that is less than twice as heavy as the top quark .
the vacuum remains stable in the model , because neutral strings are not energetically favored .
these findings suggest that extraordinarily large fermion masses or unrealistic couplings are not required to bind a cosmic string in the standard model . .
And you have already written the first three sentences of the full article: it is well known that the electroweak standard model and many of its extensions have the potential to support string like configurations that are the particle physics analogs of vortices or magnetic flux tubes in condensed matter physics .
such objects are usually called _ cosmic strings _ to distinguish them from the fundamental variables in string theory , and also to indicate that they typically stretch over cosmic length scales .
they are also called electroweak strings or @xmath0strings@xcite@xcite because the @xmath0component of the electroweak gauge boson acquires the structure of the abelian nielsen olesen vortex@xcite ..
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such strings may have emerged copiously in the early universe at interfaces between regions of different vacuum expectation values of the higgs field(s ) in several stages after the big bang until electroweak symmetry breaking was reached . if strings are absolutely stable they should have survived and we should be able to observe them today . in the electroweak standard model
topologically stable strings are ruled out , but the absence of this particular stabilizing mechanism does not imply that electroweak strings are unstable or irrelevant for particle physics . while their direct gravitational effects are negligible , @xmath0strings can still be relevant for cosmology at a sub dominant level@xcite .
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Suppose that you have an abstract for a scientific paper: we report on the identification of a third , new ultraluminous x - ray source ( ulx ) in the starburst galaxy m82 . previously , the source was observed at fluxes consistent with the high state of galactic black hole binaries ( bhbs ) .
we observe fluxes up to @xmath0 ergs s@xmath1 in the ultraluminous regime .
when the source is not in the the low / hard state , spectral fitting using a multicolor disk model shows that the disk luminosity varies as the disk inner temperature raised to the power @xmath2 , consistent with the behavior of galactic bhbs in the thermal dominant state .
fitting the spectrum with a multicolor disk model with general relativistic corrections suggests that the source harbors a rapidly spinning black hole with a mass less than 100 solar masses .
a soft excess was found in the source spectrum that could be blackbody emission from a photosphere created by a massive outflow .
the source also showed soft dips during a flare . .
And you have already written the first three sentences of the full article: ultraluminous x - ray sources ( ulxs ) are nonnuclear , point - like x - ray sources in external galaxies with an apparent luminosity over the eddington limit of a stellar - mass black hole , which is typically @xmath3 ergs s@xmath1 for a 20 @xmath4 black hole .
those with variability on time scales from minutes to months are accreting compact objects .
the nature of ulxs is still unclear ..
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if the emission is ( roughly ) isotropic and under the eddington limit , they may harbor black holes up to @xmath5 @xmath4 , belonging to the missing population of intermediate - mass black holes ( imbhs ; * ? ? ?
* ; * ? ? ?
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Suppose that you have an abstract for a scientific paper: we use 2mass and _ msx _ infrared observations , along with new molecular line ( co ) observations , to examine the distribution of young stellar objects ( ysos ) in the molecular cloud surrounding the halo region kr 140 in order to determine if the ongoing star - formation activity in this region is dominated by sequential star formation within the photodissociation region ( pdr ) surrounding the region .
we find that kr 140 has an extensive population of ysos that have `` spontaneously '' formed due to processes not related to the expansion of the region .
much of the yso population in the molecular cloud is concentrated along a dense filamentary molecular structure , traced by c@xmath0o , that has not been erased by the formation of the exciting o star .
some of the previously observed submillimetre clumps surrounding the region are shown to be sites of recent intermediate and low - mass star formation while other massive starless clumps clearly associated with the pdr may be the next sites of sequential star formation .
stars : pre - main - sequence stars : formation regions infrared : stars .
And you have already written the first three sentences of the full article: this study is the fourth in a series of papers exploring the structure of the region kr 140 and its associated star - forming activity . in @xcite ves 735 , the o - star powering the region was examined .
a second paper , @xcite , was a multiwavelength study of the structure , energetics , and kinematics of the region .
finally , @xcite presented an analysis of submillimetre ( submm hereafter ) observations of the region at 450 and 850 @xmath1 m ..
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the main result of @xcite was the discovery of numerous submm dust cores located within the molecular gas surrounding the region , including a large number of cores that were clearly located at the interface between ionized and molecular gas , a likely location for star - formation induced or `` triggered '' by the expansion of the region @xcite .
two of the more isolated cores were clearly associated with _ iras _ sources , but the low resolution of _ iras _ combined with the extensive diffuse emission of dust associated with the region made it impossible to determine if any of the other cores were associated with star - formation activity .
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Suppose that you have an abstract for a scientific paper: using the riemann - liouville and caputo fractional standard maps ( fsm ) and the fractional dissipative standard map ( fdsm ) as examples , we investigate types of solutions of non - linear fractional differential equations .
they include periodic sinks , attracting slow diverging trajectories ( asdt ) , attracting accelerator mode trajectories ( amt ) , chaotic attractors , and cascade of bifurcations type trajectories ( cbtt ) .
new features discovered include attractors which overlap , trajectories which intersect , and cbtts . .
And you have already written the first three sentences of the full article: in recent years fractional calculus ( fc ) and fractional differential equations ( fde ) became very popular in many areas of science .
the books dedicated to the applications of fdes published in 2010 - 2011 include @xcite in physics in general , @xcite in modeling and control , @xcite in viscoelasticity , @xcite in systems with long - range interaction .
a good review of applications of fc to chaos in hamiltonian systems is given in @xcite . because fractional derivatives are integro - differential operators , they are used to describe systems distributed in time and/or space : systems with long range interaction @xcite , non - markovian systems with memory ( @xcite ch.10 , @xcite ) , fractal media @xcite , etc ..
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biological systems are probably the best examples of systems with memory . as it has been shown recently @xcite , even processing of external stimuli by individual neurons can be described by fractional differentiation . in some cases @xcite fdes
are equivalent to the volterra integral equations of the second kind .
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Suppose that you have an abstract for a scientific paper: the purpose of this paper is to present some results on the existence of homologous , nonisotopic symplectic or lagrangian surfaces embedded in a simply connected symplectic @xmath0-dimensional manifold . .
And you have already written the first three sentences of the full article: let @xmath1 be a closed simply connected symplectic @xmath0-manifold and let @xmath2 be a symplectic form on @xmath1 , i.e. a closed , nondegenerate @xmath3-form .
a closed ( oriented ) embedded surface @xmath4 is called + - _ symplectic _ if @xmath5 restricts to a symplectic form on @xmath6 , i.e. @xmath7 ; + - _ lagrangian _ if @xmath5 restricts to the trivial form on @xmath6 , i.e. @xmath8 . given two submanifolds representing the same homology class , we say that they are isotopic if they can be joined by a family of embedded submanifolds . by the isotopy extension theorem ( see e.g. @xcite ) , this is equivalent to the existence of an ambient isotopy of @xmath1 connecting them .
isotopic submanifolds are essentially the same , from the point of view of the smooth topology of @xmath1 , so in order to study the topological aspects of symplectic and lagrangian submanifolds of @xmath1 we need to take into account the equivalence relation above ..
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this leads to the following + * problem * ( p ) : fix a homology class @xmath9 ; classify all the symplectic ( lagrangian ) representatives of @xmath10 up to the equivalence relation above . +
this problem was first posed , in the study of lagrangian @xmath11 s linear outside a ball in @xmath12 ( where the homology condition becomes irrelevant ) by arnold in @xcite , and further generalized , also in the lagrangian case , by eliashberg and polterovich ( see @xcite ) .
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Suppose that you have an abstract for a scientific paper: we have found a new evolutionary path to type ia supernovae ( sne ia ) which has been overlooked in previous work . in this scenario , a carbon - oxygen white dwarf ( c+o wd ) is originated , not from an asymptotic giant branch star with a c+o core , but from a red - giant star with a helium core of @xmath0 .
the helium star , which is formed after the first common envelope evolution , evolves to form a c+o wd of @xmath1 with transferring a part of the helium envelope onto the secondary main - sequence star .
this new evolutionary path , together with the optically thick wind from mass - accreting white dwarf , provides a much wider channel to sne ia than previous scenarios .
a part of the progenitor systems are identified as the luminous supersoft x - ray sources or the recurrent novae like u sco , which are characterized by the accretion of helium - rich matter .
the white dwarf accretes hydrogen - rich , helium - enhanced matter from a lobe - filling , slightly evolved companion at a critical rate and blows excess matter in the wind .
the white dwarf grows in mass to the chandrasekhar mass limit and explodes as an sn ia .
a theoretical estimate indicates that this channel contributes a considerable part of the inferred rate of sne ia in our galaxy ,
i.e. , the rate is about ten times larger than the previous theoretical estimates for white dwarfs with slightly evolved companions . .
And you have already written the first three sentences of the full article: type ia supernovae ( sne ia ) have been widely believed to be a thermonuclear explosion of a mass - accreting white dwarf ( wd ) ( e.g. , @xcite for a recent review ) .
however , the immediate progenitor binary systems have not been identified yet ( @xcite ) .
there exist two models discussed frequently as progenitors of sne ia : 1 ) the chandrasekhar ( ch ) mass model , in which a mass - accreting carbon - oxygen ( c+o ) wd grows in mass up to the ch mass and explodes as an sn ia , and 2 ) the sub - chandrasekhar ( sub - ch ) mass model , in which an accreted layer of helium atop a c+o wd ignites off - center for a wd mass well below the ch mass ..
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the early time spectra of the majority of sne ia are in excellent agreement with the synthetic spectra of the ch mass models , while the spectra of the sub - ch mass models are too blue to be comparable with the observations ( @xcite ; @xcite ) . for the evolution of accreting wds toward the ch mass ,
two scenarios have been proposed : 1 ) a double degenerate ( dd ) scenario , i.e. , merging of double c+o wds with a combined mass surpassing the ch mass limit ( @xcite ; @xcite ) , and 2 ) a single degenerate ( sd ) scenario , i.e. , accretion of hydrogen - rich matter via mass transfer from a binary companion ( e.g. , @xcite ; @xcite ) . the issue of dd vs. sd
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Suppose that you have an abstract for a scientific paper: we propose a predictive standard model for heavy electron systems based on a detailed phenomenological two - fluid description of existing experimental data .
it leads to a new phase diagram that replaces the doniach picture , describes the emergent anomalous scaling behavior of the heavy electron ( kondo ) liquid measured below the lattice coherence temperature , @xmath0 , seen by many different experimental probes , that marks the onset of collective hybridization , and enables one to obtain important information on quantum criticality and the superconducting / antiferromagnetic states at low temperatures . because @xmath0 is @xmath1 , the nearest neighbor rkky interaction , a knowledge of the single - ion kondo coupling , @xmath2 , to the background conduction electron density of states , @xmath3 , makes it possible to predict kondo liquid behavior , and to estimate its maximum superconducting transition temperature in both existing and newly discovered heavy electron families . .
And you have already written the first three sentences of the full article: although we have yet to obtain a microscopic solution of the kondo lattice problem that serves as a model for heavy electron materials , thanks to a recent phenomenological analysis @xcite of decades of experimental efforts on heavy electron behavior , we now have an experiment - based model for their behavior that explains existing experiments and has predictive power in the exploration of new families of heavy electron materials .
our model provides a unified explanation of the emergence of the heavy electron kondo liquid that is responsible for the anomalies seen in the knight shift , magneto - transport , and other experiments , leads to a new phase diagram that replaces the doniach picture , and has the potential for becoming the standard model of heavy electron physics .
it contains several basic aspects : * there exists a unique temperature scale @xmath0 for each heavy electron material ; it marks the emergence of a new state of matter , a coherent heavy electron ( kondo ) liquid that is produced by the collective hybridization of the local moments with the conduction electron sea , and exhibits universal behavior that scales with @xmath0@xcite ..
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* @xmath0 is the nearest neighbor rkky ( ruderman - kittel - kasuya - yosida ) local moment interaction ; for the local moments it separates their high-@xmath4 weakly interacting phase from their low-@xmath4 entangled phase .
it is given by @xmath5@xmath6 , where @xmath2 is the single - ion kondo coupling to the background conduction electron density of states @xmath3 @xcite .
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Suppose that you have an abstract for a scientific paper: it is claimed in another paper that the collapse of a quantum mechanical wave function is more than invariant , it is trans - representational . it must occur along a fully invariant surface .
the obvious surface available for this purpose is that of the backward time cone of the collapse event as proposed by hellwig and kraus . this collapse is widely believed to result in paradoxical causal loops that can not be removed by special relativistic and/or standard quantum mechanical considerations alone .
however , the paradox is resolved when we apply the qrule foundation theory that is developed in the other paper .
the causal and temporal orders of state reduction are then found to be in agreement with one another , and the resulting boundaries in minkowski space are shown to have a novel architecture that limits the range of a hellwig - kraus reduction in space and time . although these boundaries have been worked out using the qrules , they should be the same for any foundation theory that treats the collapse of a wave in an invariant way , and requires that a collapse destroys the possibility of any further influence on itself as do the qrules .
keywords : measurement , state reduction , wave collapse . .
And you have already written the first three sentences of the full article: the collapse of a wave function is an undeniable feature of individual quantum mechanical systems .
however , the collapse of a state along a @xmath0 = constant surface of an arbitrary coordinate system is unbelievable , inasmuch as nature does not recognize a surface that is so obviously constructed by humans . for this reason , a foundation theory must provide for the collapse of a wave along an invariant surface that is independent of coordinate representations .
the collapse of a wave is not just invariant , it is trans - representational ; that is , it is independent of any choice of basis states ..
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furthermore , it will collapse along the surface of the backward time cone that is here called a _ conic _ surface .
this is the hellwig and kraus state reduction @xcite that has been widely dismissed as being causally problematic @xcite .
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Suppose that you have an abstract for a scientific paper: we study theoretically the capturing of paramagnetic beads by a magnetic field gradient in a microfluidic channel treating the beads as a continuum .
bead motion is affected by both fluidic and magnetic forces .
the transfer of momentum from beads to the fluid creates an effective bead - bead interaction that greatly aids capturing .
we demonstrate that for a given inlet flow speed a critical density of beads exists above which complete capturing takes place . .
And you have already written the first three sentences of the full article: recently , there has been an increasing interest in using magnetic beads in separation of , say , biochemical species in microfluidic systems @xcite . the principle is to have biochemically functionalized polymer beads with inclusions of superparamagnetic nanometersize particles of , for example , magnetite or maghemite .
they attach to particular biochemical species and can be separated out from solution by applying external magnetic fields . as most biological material is either diamagnetic or weakly paramagnetic , this separation is specific .
paramagnetic particles in fluids are also used to measure the susceptibility of , for example , magnetically labelled cells by measuring particle capture or motion in a known field @xcite . in this paper.
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we study microfluidic capturing of paramagnetic beads from suspension by modeling the beads as a continuous distribution @xcite .
the separation of suspended paramagnetic beads from their host fluid is an important process as it decides operating characteristics for practical microfluidic devices .
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Suppose that you have an abstract for a scientific paper: the structures produced during the epoch of reionization by the action of radiation on neutral hydrogen are in principle different to those that arise through gravitational growth of initially small perturbations .
we explore the difference between the two mechanisms using high resolution cosmological radiative transfer .
our computations use a monte carlo code which raytraces directly through sph kernels without a grid , preserving the high spatial resolution of the underlying hydrodynamic simulation .
because the properties of the first sources of radiation are uncertain , we simulate a range of models with different source properties and recombination physics .
we examine the morphology of the neutral hydrogren distribution and the reionization history in these models .
we find that at fixed mean neutral fraction , structures are visually most affected by the existence of a lower limit in source luminosity , then by galaxy mass to light ratio , and are minimally affected by changes in the recombination rate and amplitude of mass fluctuations .
we concentrate on the autocorrelation function of the neutral hydrogen , @xmath0 as a basic quantitive measure of radiation induced structure ( ris . )
all the models we test exhibit a characteristic behaviour , with @xmath1 becoming initially linearly antibiased with respect to the matter correlation function , reaching a minimum bias factor @xmath2 when the universe is @xmath3 ionized . after this
@xmath1 increases rapidly in amplitude , overtaking the matter correlation function .
it keeps a power law shape , but flattens considerably , reaching an asymptotic logarithmic slope of @xmath4 .
the growth rate of @xmath5 fluctuations is exponentially more rapid than gravitational growth over a brief interval of redshift @xmath6 .
[ firstpage ] cosmology : observations large - scale structure of universe .
And you have already written the first three sentences of the full article: in the standard cosmological model , the large - scale structure in the density field grows from small initial perturbations through the mechanism of gravitational instability .
statistical measures of this structure can be used to both verify the growth mechanism ( see e.g. , bernardeau 2002 and references therein ) and quantify the initial pertubations . a different kind of growth of structure is expected when we consider the neutral hydrogen density field during the epoch of reionization ( see e.g. , the review by loeb & barkana 2001 ) . in this case , bubbles of ionized material form first around bright sources and grow as the ionization fronts overlap until the universe is fully ionized .
statistical measures applied to this `` radiation induced structure '' ( hereafter ris ) can be used in a similar way to the gravitational instability picture above , but this time to verify the process of reionization and the nature of the sources of radiation ..
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the effect of ris is likely to be qualitatively different from that of gravity , and as a result the statistical signatures will be different . our aim in this paper is to explore the differences , using ray traced simulations of reionization .
we aim to both find out how reionization is different from gravity in the way it forms structure and how to use these differences to categorize reionization scenarios .
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Suppose that you have an abstract for a scientific paper: we present first results from the southern cosmology survey , a new multiwavelength survey of the southern sky coordinated with the atacama cosmology telescope ( act ) , a recently commissioned ground - based mm - band cosmic microwave background experiment .
this article presents a full analysis of archival optical multi - band imaging data covering an 8 square degree region near right ascension 23 hours and declination -55 degrees , obtained by the blanco 4-m telescope and mosaic - ii camera in late 2005 .
we describe the pipeline we have developed to process this large data volume , obtain accurate photometric redshifts , and detect optical clusters . our cluster finding process uses the combination of a matched spatial filter , photometric redshift probability distributions and richness estimation .
we present photometric redshifts , richness estimates , luminosities , and masses for 8 new optically - selected clusters with mass greater than @xmath0 at redshifts out to 0.7 .
we also present estimates for the expected sunyaev - zeldovich effect ( sze ) signal from these clusters as specific predictions for upcoming observations by act , the south pole telescope and atacama pathfinder experiment . .
And you have already written the first three sentences of the full article: the new generation of high - angular resolution cosmic microwave background ( cmb ) ground - based experiments represented by the the atacama cosmology telescope ( act ) @xcite and the south pole telescope ( spt ) @xcite are currently targeting their observations in a common area in the southern sky that will ultimately cover several hundreds to thousands of square degrees . these experiments will provide a blind survey of the oldest light in the universe at wavelengths of @xmath1 mm and angular scales beyond the resolution limits of the wmap and planck satellites . at these arcminute angular scales , temperature fluctuations in the cmb are dominated by secondary effects arising from the formation of large - scale structure in the universe .
one of the strongest effects is the imprint left by galaxy clusters though the sunyaev zeldovich effect ( sze ) @xcite in which cmb photons suffer inverse compton scattering by the hot intracluster gas .
act and spt are designed to detect the sze , through its frequency - dependence : these experiments will measure temperature shifts of the cmb radiation corresponding to a decrement below and an increment above the `` null '' frequency around 220 ghz ..
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much can be learned about the universe from these surveys .
first , accurate systematics - free maps will allow measurement of the primary power spectrum of temperature fluctuations at all scales on which they are the dominant contribution .
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Suppose that you have an abstract for a scientific paper: starting with next - generation experiments , flavor physics fully enters the era of precision measurements .
the focus shifts from testing the standard model to finding and characterizing new physics contributions .
we review the opportunities offered by future flavor experiments , discussing the expected sensitivities of the most important measurements .
we also present some examples of measurable deviations from the standard model in the flavor sector generated in a selection of new physics models , demonstrating the major contribution that precision flavor physics could give to the effort of going beyond the standard model .
* lal 11 - 245 * + october 2011 * physics opportunities at the next generation + of precision flavor physics * + + + + .
And you have already written the first three sentences of the full article: up to now the standard model ( sm ) managed to pass all the experimental challenges unscathed , providing an overall good description of particle physics up to the energy scales probed in experiments so far , namely hundreds of gev .
the higgs boson , the last missing building block of the sm , is being searched for at the lhc experiments atlas and cms , which will be able to find or exclude it . in spite of the phenomenological success , however , the sm is not satisfactory for several theoretical reasons , including the instability of the fundamental scale of weak interactions , the fermi scale , against radiative corrections , the absence of a dark matter candidate , an amount of cp violation too small to account for the matter - antimatter asymmetry in the universe , the lack of an explanation for the origin of flavor and cp violation and the non - unified description of the interactions , with gravity completely missing . for these reasons ,
the sm is regarded as a low - energy theory bound to fail at some energy scale larger than the fermi scale , where new physics ( np ) effects become important ..
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the search for these effects beyond the sm is the main goal of particle physics in the next decades , both at present and future experimental facilities .
the most straightforward way to search for np is producing and observing new particles in colliders . to this end
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Suppose that you have an abstract for a scientific paper: we study the evolution of a magnetic arcade that is anchored to an accretion disk and is sheared by the differential rotation of a keplerian disk . by including an extremely low external plasma pressure at large distances , we obtain a sequence of axisymmetric magnetostatic equilibria and
show that there is a fundamental difference between field lines that are affected by the plasma pressure and those are not ( i.e. , force - free ) .
force - free fields , while being twisted by the differential rotation of the disk , expand outward at an angle of @xmath0 away from the rotation axis , consistent with the previous studies .
these force - free field lines , however , are enclosed by the outer field lines which originate from small disk radii and come back to the disk at large radii .
these outer fields experience most of the twist , and they are also affected most by the external plasma pressure . at large cylindrical radial distances ,
magnetic pressure and plasma pressure are comparable so that any further radial expansion of magnetic fields is prevented or slowed down greatly by this pressure .
this hindrance to cylindrical radial expansion causes most of the added twist to be distributed on the ascending portion of the field lines , close to the rotation axis .
since these field lines are twisted most , the increasing ratio of the toroidal @xmath1 component to the poloidal component @xmath2 eventually results in the collimation of magnetic energy and flux around the rotation axis .
we discuss the difficulty with adding a large number of twists within the limitations of the magnetostatic approximation . .
And you have already written the first three sentences of the full article: the process of forming collimated jets / outflows due to disk accretion onto central compact objects is thought to depend on how magnetic fields behave when they are swirled around by the accretion disk .
the progress of understanding this process has , however , been hindered by the significant lack of knowledge on the global magnetic field configuration in / near the accretion disk ( see okamoto 1999 for detailed critiques on many mhd models ; see also blandford 2000 for a recent review ) .
an ordered magnetic field is widely thought to have an essential role in jet formation from a rotating accretion disk ..
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two main regimes have been considered in theoretical models ( see lovelace , ustyugova & koldoba 1999 for a review ) , the _ hydromagnetic regime _ where the energy and angular momentum is carried by both the electromagnetic field and the kinetic flux of matter , and the _ poynting flux regime _ where the energy and angular momentum outflow from the disk is carried predominantly by the electromagnetic field .
major progress has been made recently in the hydromagnetic regime of jet formation , originally proposed by blandford & payne ( 1982 ) .
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Suppose that you have an abstract for a scientific paper: a non - relativistic quantum mechanical model for interaction of dark particles with matter is proposed ; the model describes resonant amplification of effective interaction between two massive bodies at large distances between them .
the phenomenon is explained by catalytic action by a third dark particle scattered at a system of two heavy bodies . it is shown that effective interaction between the heavy bodies is changed at larger distances and can transform into repulsion contributing in that case to the dark energy action . * n. takibayev * institute of experimental and theoretical physics al - farabi kazakh national university al - farabi 71 , almaty 050040 , kazakhstan * subject classification : * 03.65nk ; 21.45.+v ; 95.35.+d + * keywords : * dark particles , three - body system , resonance distances .
And you have already written the first three sentences of the full article: as it is known , the dark matter problem arose from analysis of astronomical data when considerable discrepancy between orbital velocities of stellar objects at periphery of large galaxies compared to velocities calculated for usual gravitational fields has been found ( see , for instance , reviews in [ 8 , 14 ] ) .
this phenomenon was explained by the dark matter action that resulted in increased mass of such stellar objects . discovered effect of gravitational lensing considerably supported such assumption .
a particular obstacle was to provide experimental verification for existence of the dark matter particles ..
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many candidates for such particles have been proposed as well as several theories for their interaction with ordinary matter were considered [ 1 , 15 ] .
still , particles of dark matter have not been found .
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Suppose that you have an abstract for a scientific paper: we present a simple theoretical framework to describe the thermal noise of a microscopic mechanical beam in a viscous fluid : we use the sader approach to describe the effect of the surrounding fluid ( added mass and viscous drag ) , and the fluctuation dissipation theorem for each flexural modes of the system to derive a general expression for the power spectrum density of fluctuations .
this prediction is compared with an experimental measurement on a commercial atomic force microscopy cantilever in a frequency range covering the two first resonances .
a very good agreement is found on the whole spectrum , with no adjustable parameters but the thickness of the cantilever . .
And you have already written the first three sentences of the full article: cantilevers of micrometer size are nowadays present in many applications , ranging from chemical and biological sensors@xcite to scanning probe microscopy@xcite . in many cases , these tiny mechanical systems operate in a fluid environment ( air or water for instance ) which has a great influence on their dynamical behavior : the viscosity of the medium will broaden the structural resonances while the added mass due to the fluid moving along with the cantilever will shift their frequencies .
a few theoretical models have been proposed to account for these effects @xcite , and validated experimentally @xcite . among the prediction of these approaches ,
the power spectrum of thermal noise induced fluctuations is of particular interest for its applications in atomic force microscopy ( afm ) or micro - electromechanical systems ( mems ) ..
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we will focus here on the approach by sader et al .
@xcite , and derive a generic formula for the thermal noise using the fluctuation dissipation theorem for each mode , extending the work of paul and cross @xcite in a simpler framework than dorignac et al.@xcite .
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Suppose that you have an abstract for a scientific paper: high energy particles behavior including fusion born alpha particles in an iter like tokamak in the presence of background driftwave turbulence is investigated by an orbit following calculation .
the background turbulence is given by the toroidal driftwave eigenmode combined with a random number generator .
the transport level is reduced as the particle energy increase ; the widths of the guiding center islands produced by the passing particles are inverse proportional to the square root of parallel velocities . on the other hand ,
the trapped particles are sensitive to @xmath0 drift at the banana tips whose radial displacement is larger for lower energy particles .
coulomb collisional effects are incorporated which modifies the transport process of the trapped high energy particles whose radial excursion resides in limited radial domains without collisions . .
And you have already written the first three sentences of the full article: for a self - ignited tokamak plasma , confinement of alpha particles is a crucial issue .
the alpha particles must effectively heat the bulk plasma without a spontaneous loss .
alpha particles heat electrons first and then ions through electron - ion thermal equilibriation ..
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recent gyrokinetic simulation studies have pointed out that the microinstabilities strongly affect the high energy particles transport@xcite .
another gyrokinetic study of ion temperature gradient turbulence suggested that the diffusion of the high energy particles is small@xcite .
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Suppose that you have an abstract for a scientific paper: direct searches for lepton flavor violating higgs boson decays in the @xmath0 channel have been recently reported by the cms collaboration .
the results display a slight excess of signal events with a significance of 2.5@xmath1 , which translates into a branching ratio of about @xmath2% . by interpreting these findings as a hint for beyond the standard model physics ,
we show that the type - iii 2hdm is capable of reproducing such signal while at the same time satisfying boundedness from below of the scalar potential , perturbativity , electroweak precision data , measured higgs standard decay modes and low - energy lepton flavor violating constraints .
we have found that the allowed signal strength ranges for the @xmath3 , @xmath4 and @xmath5 standard channels shrink as soon as br@xmath6% is enforced .
thus , we point out that if the excess persists , improved measurements of these channels may be used to test our type - iii 2hdm scenario . .
And you have already written the first three sentences of the full article: since the discovery of the higgs boson @xcite special effort has been made to determine its properties .
the motivation for such an effort resides on understanding the mechanism for electroweak symmetry breaking . at present ,
several aspects of the higgs boson are to some extent well known , in particular those related with some of its expected `` standard '' decay modes , namely : @xmath7 , @xmath8 , @xmath9 , @xmath10 and @xmath11 ..
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currently , measurements of these decay modes have shown compatibility with the standard model ( sm ) expectations , although with large associated uncertainties @xcite . indeed , it is due to these large uncertainties that there is still room for nonstandard decay properties , something that has encouraged such searches at the lhc as well .
searches for invisible higgs decays have been published in @xcite , while direct searches for lepton flavor violating higgs decays ( @xmath12 ) have been recently reported by the cms collaboration in @xcite . in this letter
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Suppose that you have an abstract for a scientific paper: in these proceedings , we review results for several di - boson production processes beyond nlo qcd at high transverse momenta using the vbfnlo monte - carlo program together with the loopsim method . additionally , we show for the @xmath0 production process how higher order qcd corrections can resemble anomalous coupling effects . .
And you have already written the first three sentences of the full article: di - boson production processes are important channels to test the standard model ( sm ) at the lhc .
they have been studied intensively in the past years both from the theoretical and the experimental side . as a signal , they are sensitive to triple gauge boson couplings , and therefore , provide a unique avenue to quantify deviations from the sm predictions .
furthermore , they are a background to many sm and beyond standard model analyses . due to the large size of the next - to - leading order(nlo ) corrections and the expected percent precision measurement at the lhc ,.
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the theoretical community has pursued in the last years the task to provide next - to - next - to - leading order ( nnlo ) qcd results .
this task has been almost completed in the last years and exact results at nnlo are known for most of the processes , not only for total cross sections @xcite , but also for differential distributions @xcite . at the same time , due to the large collection of results known at nlo for processes with different jet multiplicities , a field by its own has emerged with the aim to merge in a consistent way processes with different jet multiplicities at nlo . in this letter , following the loopsim approach @xcite , we will merge @xmath1 and @xmath1+jet samples and review results at approximate nnlo accuracy for several di - boson production processes .
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11,591 |
Suppose that you have an abstract for a scientific paper: ab initio calculations using the local spin density approximation and also including the hubbard @xmath0 have been performed for three low energy configurations of the interface between laalo@xmath1 and tio@xmath2-anatase .
two types of interfaces have been considered : lao / tio@xmath2 and alo@xmath2/tio , the latter with ti - termination and therefore a missing oxygen .
a slab - geometry calculation was carried out and all the atoms were allowed to relax in the direction normal to the interface . in all the cases considered ,
the interfacial ti atom acquires a local magnetic moment and its formal valence is less than @xmath3 .
when there are oxygen vacancies , this valence decreases abruptly inside the anatase slab while in the lao / tio@xmath2 interface the changes are more gradual .
+ 3 mm .
And you have already written the first three sentences of the full article: complex oxide heterostructures have been the subject of many recent papers , both experimental and theoretical , as their interesting interface properties promise to pave the way towards novel electronic devices . with the current available experimental techniques oxide thin films
can be produced with a high degree of cristallinity and the electronic structure of their surfaces and interfaces can be precisely determined .
the most studied system of this type has been laalo@xmath1/srtio@xmath1 ( lao / sto ) , that consists of two perovskite structures stacked along the ( 001 ) direction@xcite , in which they present alternate layers of lao , alo2 , tio2 and sro with a very small lattice mismatch between them . a similar but.
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less studied interface is that of lao with tio@xmath2-anatase , that presents an even smaller lattice mismatch , namely less than 0.1% , along the ( 001 ) direction @xcite .
tio2 is a key material for most applications , including catalytic and optical devices , sensors , optoelectronics and spintronics .
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Suppose that you have an abstract for a scientific paper: we consider the one - person game of peg solitaire played on a computer .
two popular board shapes are the 33-hole cross - shaped board , and the 15-hole triangular board we use them as examples throughout .
the basic game begins from a full board with one peg missing and finishes at a board position with one peg .
first , we discuss ways to solve the basic game on a computer .
then we consider the problem of quickly distinguishing boards positions that can be reduced to one peg ( winning " board positions ) from those that can not be solved to one peg ( losing " board positions ) .
this enables a computer to alert the player if a jump under consideration leads to a dead end .
on the 15-hole triangular board , it is possible to identify all winning board positions ( from any single vacancy start ) by storing a key set of 437 board positions . for the central game " on the 33-hole cross - shaped board
, we can identify all winning board positions by storing 839,536 board positions .
+ [email protected] + .2 in .
And you have already written the first three sentences of the full article: peg solitaire is one of the earliest known puzzles , with a 300 year history .
the puzzle consists of a game board together with a number of pegs , or more commonly marbles .
the board contains a grid of holes in which these pegs or marbles are placed ..
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figure [ fig1 ] shows the two most common shapes for a peg solitaire board , the 33-hole cross - shaped board , and the 15-hole triangular board .
the game is played by jumping one peg over another into an empty hole , removing the peg that was jumped over . on the cross - shaped board of figure [ fig1]a ,
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Suppose that you have an abstract for a scientific paper: the usage of the high - level scripting language python has enabled new mechanisms for data interrogation , discovery and visualization of scientific data .
we present ` yt ` , an open source , community - developed astrophysical analysis and visualization toolkit for data generated by high - performance computing ( hpc ) simulations of astrophysical phenomena . through a separation of responsibilities in the underlying python code , ` yt ` allows data generated by incompatible , and sometimes even directly competing , astrophysical simulation platforms to be analyzed in a consistent manner , focusing on physically relevant quantities rather than quantities native to astrophysical simulation codes .
we present on its mechanisms for data access , capabilities for mpi - parallel analysis , and its implementation as an _ in situ _ analysis and visualization tool . .
And you have already written the first three sentences of the full article: in the last decade , multiphysics astrophysical simulations have increased exponentially in both sophistication and size @xcite ; however , the software tools to mine those simulations have not kept pace .
typically , methods for examining data suffer from a lack of agility , discouraging exploratory investigation . to accommodate this
, massively parallel visualization tools such as visit and paraview @xcite have been repurposed as domain - specific astrophysical tools ..
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this repurposing , while effective , does not benefit from domain - specific analysis or data structures .
the lack of domain - specific quantitative analysis tools designed for astrophysical data leads to the development of specialized tools by individual researchers or research groups , most of which are never shared outside the research group .
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Suppose that you have an abstract for a scientific paper: a novel functional integral formulation of quantum mechanics for non - lagrangian systems is presented .
the new approach , which we call `` stringy quantization , '' is based solely on classical equations of motion and is free of any ambiguity arising from lagrangian and/or hamiltonian formulation of the theory .
the functionality of the proposed method is demonstrated on several examples .
special attention is paid to the stringy quantization of systems with a general @xmath0-power friction force @xmath1 .
results for @xmath2 are compared with those obtained in the approaches by caldirola - kanai , bateman and kostin .
relations to the caldeira - leggett model and to the feynman - vernon approach are discussed as well .
dedicated to my father on the occasion of his 60th birthdays . .
And you have already written the first three sentences of the full article: quantization is a phenomenon that changes our bright classical perspective into a bit uncertain and at first sight rather nonintuitive picture .
this picture , however , is more rigorous than the classical one , possesses many fascinating features and has produced a lot of successful predictions .
the subtle problem of transition from classical to quantal attracts attention from the early days of quantum mechanics . over the years.
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various techniques and methods for solving this puzzle have been invented .
our aim is not to trace back the complete ( hi)story of the milestone ideas in this field ( for the review we refer to @xcite ) .
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Suppose that you have an abstract for a scientific paper: recently , the @xmath0 and @xmath1 radiative corrections to the orthopositronium lifetime have been presented in closed analytical form , in terms of basic irrational numbers that can be evaluated numerically to arbitrary precision [ phys .
rev .
lett .
* 101 * , 193401 ( 2008 ) ] . here
, we present the details of this calculation and reveal the nature of these new constants . we also list explicit transformation formulas for generalized polylogarithms of weight four , which may be useful for other applications . .
And you have already written the first three sentences of the full article: positronium ( ps ) , the electron - positron bound state , was discovered experimentally in 1951 @xcite . since that time
a lot of attention has been paid to the determination of its properties , including lifetime , decay modes , and spectroscopy .
the experimental and theoretical accuracies achieved by now being quite high , there is little doubt that quantum electrodynamics ( qed ) is the only interaction in this system ..
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in fact , thanks to the smallness of the electron mass @xmath2 relative to typical hadronic mass scales , its theoretical description is not plagued by strong - interaction uncertainties and its properties , such as decay widths and energy levels , can be calculated perturbatively in non - relativistic qed ( nrqed ) @xcite , as expansions in sommerfeld s fine - structure constant @xmath3 , with very high precision .
ps comes in two ground states , @xmath4 parapositronium ( @xmath5-ps ) and @xmath6 orthopositronium ( @xmath7-ps ) , which decay to two and three photons , respectively .
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11,596 |
Suppose that you have an abstract for a scientific paper: distributions of faraday rotation measure ( frm ) and the projected magnetic field derived by a 3-dimensional simulation of mhd jets are investigated based on our `` sweeping magnetic twist model '' .
frm and stokes parameters were calculated to be compared with radio observations of large scale wiggled agn jets on kpc scales .
we propose that the frm distribution can be used to discuss the 3-dimensional structure of magnetic field around jets and the validity of existing theoretical models , together with the projected magnetic field derived from stokes parameters . in the previous paper , we investigated the basic straight part of agn jets by using the result of a 2-dimensional axisymmetric simulation .
the derived frm distribution has a general tendency to have a gradient across the jet axis , which is due to the toroidal component of the magnetic field generated by the rotation of the accretion disk . in this paper
, we consider the wiggled structure of the agn jets by using the result of a 3-dimensional simulation .
our numerical results show that the distributions of frm and the projected magnetic field have a clear correlation with the large scale structure of the jet itself , namely , 3-dimensional helix .
distributions , seeing the jet from a certain direction , show a good matching with those in a part of 3c449 jet .
this suggests that the jet has a helical structure and that the magnetic field ( especially the toroidal component ) plays an important role in the dynamics of the wiggle formation because it is due to a current - driven helical kink instability in our model . .
And you have already written the first three sentences of the full article: to explain the formation of active galactic nucleus ( agn ) jets and other astrophysical jets , various models have been proposed . among them , the magnetohydorodynamic ( mhd ) model is one of the most promising models , since it can explain both the acceleration and the collimation of the jets ( see , e.g. , meier , koide , & uchida 2001 , and references therein ) .
lovelace ( 1976 ) and blandford ( 1976 ) first proposed the theoretical model of the magnetically driven jet from accretion disks , and blandford & payne ( 1982 ) discussed magneto - centrifugally driven outflow from a keplerian disk in steady , axisymmetric and self - similar situation .
time - dependent , 2-dimensional axisymmetric simulations were performed by uchida & shibata ( 1985 ) , shibata & uchida ( 1986 ) , uchida & shibata ( 1986 ) ..
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they pointed out that large amplitude torsional alfvn waves ( taws ) generated by the interaction between the accretion disk and a large scale magnetic field play an important role .
the toroidal magnetic field propagates along the large scale magnetic field while squeezing it into a collimated jet - shape by the pinching effect of the lorentz force . in this paper
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Suppose that you have an abstract for a scientific paper: the motion of a hoop hung on a spinning wire provides an illustrative and pedagogical example of a supercritical bifurcation . above a certain angular velocity threshold @xmath0 ,
the hoop rises , making an angle @xmath1 with the vertical .
the equation of motion is derived in the limit of a long massless wire , and the calculated steady states are compared to experimental measurements .
this simple experiment is suitable for classroom demonstration , and provides an interesting alternative to the classical experiment of the bead sliding on a rotation hoop . .
And you have already written the first three sentences of the full article: the rotation of rigid bodies often displays interesting instability problems .
bodies with three different inertia moments are well known to have unstable rotation about the intermediate axis @xcite , as commonly observed from acrobatic jumps or dives .
throwing a tennis racket provides an easy illustration of this instability of the free rotation ..
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such purely inertial instability has no threshold , _
i.e. _ it can be observed for very low rotation rates .
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Suppose that you have an abstract for a scientific paper: we present new sub - arcsecond - resolution near - infrared polarimetric imaging and millimetre interferometry data on the circumstellar disk system in the bok globule cb26 .
the data imply the presence of a @xmath0m@xmath1 edge - on - seen disk of @xmath2au in diameter , being in keplerian rotation around a young @xmath30.35m@xmath1 star .
the mm dust emission from the inner 200au is highly optically thick , but the outer parts are optically thin and made of small dust grains .
planetesimal growth in the inner disk could neither be comfirmed nor excluded .
we argue that the cb26 disk is a very young protoplanetary disk and show that it is comparable to the early solar system . .
And you have already written the first three sentences of the full article: observations of protostellar systems and their prominent jets and outflows suggest that accretion disks start to form very early during the main accretion phase .
these disks live much longer than the central protostar needs to build up most of its mass . when the initial protostellar core is dispersed by accretion and outflows , the central star still accretes matter at low rates from the surrounding disk . typical disk life
times around low - mass stars were shown to be at least @xmath4yrs and their masses ( typically 0.01 - 0.1m@xmath1 ) do not seem to decrease considerably during this time @xcite ..
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theoretical and laboratory studies show that the timescale for grain growth and planetesimal formation is shorter than the typical disk life time .
such disks should soon evolve into protoplanetary disks .
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Suppose that you have an abstract for a scientific paper: we have investigated the temperature and magnetic field dependence of magnetization , specific heat ( @xmath0 ) , and relative sample length change ( @xmath1 ) for understanding the field - induced spin - structural change in quasi - one - dimensional spin chain @xmath2-cov@xmath3o@xmath4 which undergoes antiferromagnetic ( afm ) transition below @xmath5@xmath615 k. analysis of @xmath0(@xmath7 ) shows that an effective @xmath8@xmath61/2 ising state is realized below 20 k , though the magnetic fluctuations persist well above @xmath5 . @xmath0 and the coefficient of linear thermal expansion ( @xmath2 ) exhibit strong @xmath9 dependence in the afm state .
we also observe a huge positive magnetostriction [ @xmath10(@xmath9)/@xmath11 below 20 k which does not show any tendency of saturation up to 9 t. with increasing field , a sharp and symmetric peak emerges below @xmath5 in both @xmath0(@xmath7 ) and @xmath2(@xmath7 ) due to field - induced first order ferrimagnetic / ferromagnetic - paramagnetic transitions .
the large value of magnetostriction below @xmath5 suggests strong spin - lattice coupling in @xmath2-cov@xmath3o@xmath4 .
+ keywords : quasi - one - dimensional , spin chain , antiferromagnetic , ferrimagnetic , field - induced peak in specific heat , thermal expansion , spin - lattice coupling .
And you have already written the first three sentences of the full article: several cobalt - based low - dimensional compounds and rare - earth - based pyrochlore oxides exhibit fascinating magnetic properties such as magnetic field ( @xmath9 ) induced spin order - disorder transition @xcite , 1/3 magnetization plateau in the @xmath12(@xmath9 ) curve @xcite , quantum phase transition @xcite and spin - structural change @xcite .
geometrical frustration due to the triangular or tetrahedral arrangement of the magnetic moments , bond frustration as a result of competing ferromagnetic ( fm ) and antiferromagnetic ( afm ) exchange interactions and large single ion anisotropy are the fundamental ingredients that eventually determine the complexity of the magnetic ground state and hence the new functionalities in these compounds . often , the ground state of the frustrated materials is extremely sensitive to external perturbations such as magnetic field .
though there are a number of systems showing such kind of magnetic ground state , the underlying mechanism responsible for the above features has not been well understood yet ..
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+ recently , the quasi - one - dimensional ( 1d ) spin - chain cov@xmath3o@xmath4 has received attention to the scientific community due to the observation of 1/3 magnetization plateau similar to that observed in a regular triangular lattice @xcite . in monoclinic @xmath2-cov@xmath3o@xmath4 and triclinic @xmath13-cov@xmath3o@xmath4 , the edge - shared coo@xmath4 octahedra form a magnetic chain along the @xmath14 axis , and the edge - shared vo@xmath15 square pyramids are located in between the magnetic chains . the much larger co - co interchain distance as compared to the intrachain co - co distance and the presence of the nonmagnetic v@xmath16 ion in between the chains weaken the interchain magnetic coupling considerably .
both @xmath2-cov@xmath3o@xmath4 and @xmath13-cov@xmath3o@xmath4 show large single ion anisotropy , undergo long - range afm transition below 15 and 6 k , respectively and exhibit field - induced metamagnetic transitions at two critical fields @xmath17 and @xmath18 @xcite .
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