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6,200 | Suppose that you have an abstract for a scientific paper: we present an efficient scheme for the generation of noon states of photons in circuit qed assisted by a superconducting charge qutrit .
it is completed with two kinds of manipulations , that is , the resonant operation on the qutrit and the resonator , and the single - qubit operation on the qutrit , and they both are high - fidelity operations . compared with the one by a superconducting transmon qutrit proposed by su et al .
( sci .
rep . * 4 * , 3898 ( 2014 ) ) , our scheme does not require to maintain the qutrit in the third excited state with a long time , which relaxes the difficulty of its implementation in experiment . moreover , the level anharmonicity of a charge qutrit is larger and it is better for us to tune the different transitions of the charge qutrit resonant to the resonator , which makes our scheme faster than others .
+ * key words : * entanglement production , noon states , microwave - photon resonators , superconducting charge qutrit , circuit qed .
And you have already written the first three sentences of the full article: quantum information is an important branch of quantum physics .
it includes mainly quantum communication and quantum computation @xcite . by far , many interesting quantum systems have been presented for quantum information processing , such as nuclear magnetic resonance @xcite , quantum dots @xcite , diamond nitrogen vacancy ( nv ) centers @xcite , photonic systems @xcite , circuit quantum electrodynamics ( qed ) @xcite , and so on . due to the good scalability @xcite and convenient operation on superconducting qubits , circuit qed has attracted much attention in recent years . composed of the superconducting circuit and the superconducting 1d resonator , circuit qed @xcite has some good characters for completing quantum information processing .
the superconducting circuit can act as a qubit perfectly ..
Please generate the next two sentences of the article | the energy - level structure of the qubit can be divided into @xmath0 , @xmath1 , @xmath2 , and @xmath3 types @xcite which can not be found in atom systems .
a relative long life time of a superconducting qubit has been realized to reach @xmath4 ms @xcite . the strong coupling strength between a superconducting qubit and a superconducting resonator @xcite has been demonstrated in the experiment . |
6,201 | Suppose that you have an abstract for a scientific paper: we apply the new formulation of heavy quark effective field theory ( hqeft ) to the inclusive decays of bottom hadrons .
the long - term ambiguity of using heavy quark mass or heavy hadron mass for inclusive decays is clarified within the framework of the new formulation of hqeft .
the @xmath0 order corrections are absent and contributions from @xmath1 terms are calculated in detail .
this enables us to reliably extract the important ckm matrix element @xmath2 from the inclusive semileptonic decay rates .
the resulting lifetime ratios @xmath3 and @xmath4 are found to well agree with the experimental data .
we also calculate in detail the inclusive semileptonic branching ratios and the ratios of the @xmath5 and @xmath6 decay rates as well as the charm countings in the @xmath7 , @xmath8 and @xmath9 systems . for @xmath7 decays ,
all the observables are found to be consistent with the experimental data .
more precise data for the @xmath7 decays and further experimental measurements for the @xmath8 and @xmath9 systems will be very useful for testing the framework of new formulation of hqeft at the level of higher order corrections . .
And you have already written the first three sentences of the full article: in our previous paper@xcite , we have provided a more detailed study on a new formulation of hqeft@xcite and applied it to evaluate the weak transition matrix elements between the heavy hadrons containing a single heavy quark .
consequently , the new formulation of hqeft has exhibited interesting features , such as : the luke s theorem comes out automatically without imposing the equation of motion @xmath10 ; the form factors at zero recoil are found to be related to the meson masses , so that the most important relevant form factors at zero recoil can be fitted from the ground state meson masses ; the number of universal form factors up to the order of @xmath11 are less than the one in the usual hqet .
it is of interest to apply the new formulation of hqeft@xcite to the inclusive decays of bottom hadrons ..
Please generate the next two sentences of the article | the inclusive decays of bottom hadrons have been investigated in the recent years by several groups@xmath12 . while it is well known that in the usual hqet there are still some problems which are not yet well understood .
these problems mainly involve the following issues : firstly , the world average values for the lifetime ratios of bottom hadrons are @xcite @xmath13 while the usual hqet prediction leads to a uniform lifetime for all the bottom hadrons when the nonspectator effects are neglected . |
6,202 | Suppose that you have an abstract for a scientific paper: we applied an improved coulomb correction method developed by us recently to data on identical @xmath0-pairs production in s + pb and @xmath1 + pb reactions at 200 gev / c obtained by na44 collaboration . to analyse
the whole range of the momentum transfers measured the method of `` seamless fitting '' has been proposed and used together with the asymptotic expansion formula for the coulomb wave function .
we found that such coulomb corrections lead sometimes to different than previously reported ( by na44 collaboration ) interaction region and strongly influence the long range correlations .
+ preprint * dpsu-95 - 4 * ( july , 1995 ) = -45pt = 0 cm = 0 cm = 23.7 cm = 16 cm * introduction : * recently na44 collaboration has reported their data on the bose - einstein correlations ( bec ) of @xmath2 pairs produced in s + pb and @xmath1 + pb reactions at 200 gev / c @xcite . in our previous work
@xcite we have analysed these data by making use of the various source functions with the long range correlation ( without , however , invoking any sort of coulomb corrections ) .
the data @xcite have been corrected for coulomb interactions by applying only the gamow factor . as was pointed out some time ago by bowler
this is , however , not sufficient @xcite . in our recent works @xcite the still improved method of coulomb corrections was presented but not yet applied to any concrete data set . in the present letter , we apply it therefore to the analysis of data for @xmath2 pairs production in s + pb and @xmath1 + pb reactions mentioned above ( in the whole measured momentum transfer region ) and compare our results with those obtained before in @xcite . to be able to analyse the whole range of measured momentum transfer @xmath3 and to avoid wild oscillations developing at large @xmath3 s ( cf .
fig .
1a ) we have to use the the asymptotic expansion of the coulomb wave function together with the procedure of `` seamless fitting '' ( sf ) explained below ( cf . figs .
1b and 2 ) . +
*....
And you have already written the first three sentences of the full article: fig . 1 . : : \(a ) analyses of data for s + pb @xmath45 reaction by eq .
( [ eq : ratio ] ) .
( b ) the same but with coulomb corrections switched off for @xmath46 limit ..
Please generate the next two sentences of the article | ( results for @xmath47 pair production looks similar with only change being in the value of @xmath48 which depend on the value of radius parameter @xmath38 . ) fig . 2 . : : flow chart for our procedure of `` seamless fitting ( sf ) '' . fig . 3 . : : results of sf for bec for kaons produced in s + pb collisions ; ( a ) for @xmath47 pairs ; ( b ) for @xmath49 pairs . fig .
4 . : : results of sf for bec for kaons produced in @xmath1 + pb @xmath45 reaction . |
6,203 | Suppose that you have an abstract for a scientific paper: we examine hilltop quintessence models , in which the scalar field is rolling near a local maximum in the potential , and @xmath0 .
we first derive a general equation for the evolution of @xmath1 in the limit where @xmath0 .
we solve this equation for the case of hilltop quintessence to derive @xmath2 as a function of the scale factor ; these solutions depend on the curvature of the potential near its maximum .
our general result is in excellent agreement ( @xmath3 ) with all of the particular cases examined .
it works particularly well ( @xmath4 ) for the pseudo - nambu - goldstone boson potential .
our expression for @xmath5 reduces to the previously - derived slow - roll result of sen and scherrer in the limit where the curvature goes to zero . except for this limiting case
, @xmath5 is poorly fit by linear evolution in @xmath6 . .
And you have already written the first three sentences of the full article: observational evidence @xcite suggests that approximately 70% of the energy density in the universe is in the form of an exotic , negative - pressure component , dubbed dark energy .
( for a recent review , see , e.g. , ref .
the observational bounds on the properties of the dark energy have continued to tighten ..
Please generate the next two sentences of the article | taking @xmath2 to be the ratio of pressure to density for the dark energy : @xmath7 recent observational constraints are typically @xmath8 when @xmath2 is assumed constant ( see , e.g. , @xcite and references therein ) .
one possibility is that the dark energy is , in fact , merely a cosmological constant , with @xmath2 exactly equal to @xmath9 . |
6,204 | Suppose that you have an abstract for a scientific paper: we show that the statistics of fluctuation - driven initial - state anisotropies in proton - proton , proton - nucleus and nucleus - nucleus collisions is to a large extent universal .
we propose a simple parameterization for the probability distribution of the fourier coefficient @xmath0 in harmonic @xmath1 , which is in good agreement with monte - carlo simulations .
our results provide a simple explanation for the 4-particle cumulant of triangular flow measured in pb - pb collisions , and for the 4-particle cumulant of elliptic flow recently measured in p - pb collisions . both arise as natural consequences of the condition that initial anisotropies are bounded by unity .
we argue that the initial rms anisotropy in harmonic @xmath1 can be directly extracted from the measured ratio @xmath2 : this gives direct access to a property of the initial density profile from experimental data .
we also make quantitative predictions for the small lifting of degeneracy between @xmath3 , @xmath4 and @xmath5 .
if confirmed by future experiments , they will support the picture that long - range correlations observed in p - pb collisions at the lhc originate from collective flow proportional to the initial anisotropy . .
And you have already written the first three sentences of the full article: a breakthrough in our understanding of high - energy nuclear collisions is the recognition @xcite that quantum fluctuations in the wavefunctions of projectile and target , followed by hydrodynamic expansion , result in unique long - range azimuthal correlations between outgoing particles .
the importance of these fluctuations was pointed out in the context of detailed analyses of elliptic flow in nucleus - nucleus collisions @xcite .
it was later realized that fluctuations produce triangular flow @xcite , which has subsequently been measured in nucleus - nucleus collisions at rhic @xcite and lhc @xcite ..
Please generate the next two sentences of the article | recently , fluctuations were predicted to generate significant anisotropic flow in proton - nucleus collisions @xcite , which quantitatively explains @xcite the long - range correlations observed by lhc experiments @xcite .
recently , the atlas and cms experiments reported the observation of a nonzero 4-particle cumulant of azimuthal correlations , dubbed @xmath6 , in proton - nucleus collisions @xcite . |
6,205 | Suppose that you have an abstract for a scientific paper: the pan andromeda archeological survey ( pandas ) cfht megaprime survey of the m31-m33 system has found a star stream which extends about 120 kpc nw from the center of m31 .
the great length of the stream , and the likelihood that it does not significantly intersect the disk of m31 , means that it is unusually well suited for a measurement of stream gaps and clumps along its length as a test for the predicted thousands of dark matter sub - halos .
the main result of this paper is that the density of the stream varies between zero and about three times the mean along its length on scales of 2 to 20 kpc .
the probability that the variations are random fluctuations in the star density is less than @xmath0 . as a control sample
we search for density variations at precisely the same location in stars with metallicity higher than the stream , [ fe / h]=[0 , -0.5 ] and find no variations above the expected shot noise .
the lumpiness of the stream is not compatible with a low mass star stream in a smooth galactic potential , nor is it readily compatible with the disturbance caused by the visible m31 satellite galaxies .
the stream s density variations appear to be consistent with the effects of a large population of steep mass function dark matter sub - halos , such as found in lcdm simulations , acting on an approximately 10 gyr old star stream .
the effects of a single set of halo substructure realizations are shown for illustration , reserving a statistical comparison for another study . .
And you have already written the first three sentences of the full article: galactic halos formed from lcdm initial conditions in n - body simulations have approximately 10% of their mass in orbiting sub - halos @xcite . the gravitational stirring and heating of a galactic disk and halo star clusters by dark sub - halos
is tempered by the large numbers , high random velocities and broad distribution of sub - halos throughout the overall dark halo . however ,
very low velocity dispersion star streams in galactic halos are sensitive to the degree to which the dark matter in the halo is sub - structured into thousands of orbiting sub - halos . the sub - halos fold and chop the star - streams and gradually increase the velocity dispersion around the mean motion to about @xmath115% of the halo circular velocity , typically 30 , over a hubble time @xcite ..
Please generate the next two sentences of the article | consequently , cool star streams are sensitive indicators of the presence of the predicted dark matter substructure .
about half a dozen of the currently known milky way streams qualify as cool ( most confidently , pal 5 , gd-1 , orphan , archeron and styx ) that is , having local velocity dispersions below about 10 , or , width less than about 0.1 radian as seen from the center of the host galaxy . |
6,206 | Suppose that you have an abstract for a scientific paper: we develop an enhanced technique for characterizing quantum optical processes based on probing unknown quantum processes only with coherent states .
our method substantially improves the original proposal [ m. lobino et al . , science * 322 * , 563 ( 2008 ) ] , which uses a filtered glauber - sudarshan decomposition to determine the effect of the process on an arbitrary state .
we introduce a new relation between the action of a general quantum process on coherent state inputs and its action on an arbitrary quantum state .
this relation eliminates the need to invoke the glauber - sudarshan representation for states ; hence it dramatically simplifies the task of process identification and removes a potential source of error .
the new relation also enables straightforward extensions of the method to multi - mode and non - trace - preserving processes .
we illustrate our formalism with several examples , in which we derive analytic representations of several fundamental quantum optical processes in the fock basis .
in particular , we introduce photon - number cutoff as a reasonable physical resource limitation and address resource vs accuracy trade - off in practical applications .
we show that the accuracy of process estimation scales inversely with the square root of photon - number cutoff . .
And you have already written the first three sentences of the full article: assembling a complex quantum optical information processor requires precise knowledge of the properties of each of its components , i.e. , the ability to predict the effect of the components on an arbitrary input state .
this gives rise to a quantum version of the famous black box problem
, which is addressed by means of _ quantum process tomography _ ( qpt ) @xcite . in qpt ,.
Please generate the next two sentences of the article | a set of probe states is sent into the black box ( here an unknown completely - positive , linear quantum process @xmath0 over the set of bounded operators @xmath1 on a hilbert space @xmath2 ) and the output states are measured . from the effect of the process on the probe
states it is possible to predict its effect on any other state within the same hilbert space . |
6,207 | Suppose that you have an abstract for a scientific paper: we discuss physical properties of ` integer ' topological phases of bosons in d=3 + 1 dimensions , protected by internal symmetries like time reversal and/or charge conservation .
these phases invoke interactions in a fundamental way but do _ not _ possess topological order and are bosonic analogs of free fermion topological insulators and superconductors .
while a formal cohomology based classification of such states was recently discovered , their physical properties remain mysterious . here
we develop a field theoretic description of several of these states and show that they possess unusual surface states , which if gapped , must either break the underlying symmetry , or develop topological order . in the latter case ,
symmetries are implemented in a way that is forbidden in a strictly two dimensional theory . while this is the usual fate of the surface states , exotic gapless states
can also be realized .
for example , tuning parameters can naturally lead to a deconfined quantum critical point or , in other situations , a fully symmetric vortex metal phase .
we discuss cases where the topological phases are characterized by quantized magnetoelectric response @xmath0 , which , somewhat surprisingly , is an odd multiple of @xmath1 .
two different surface theories are shown to capture these phenomena - the first is a nonlinear sigma model with a topological term .
the second invokes vortices on the surface that transform under a _ projective _ representation of the symmetry group .
a bulk field theory consistent with these properties is identified , which is a multicomponent @xmath2 theory supplemented , crucially , with a topological term .
bulk sigma model field theories of these phases are also provided . a possible topological phase characterized by the thermal analog of the magnetoelectric effect
is also discussed . .
And you have already written the first three sentences of the full article: following the discovery of topological insulators@xcite , intense theoretical efforts have resulted in a good understanding of topological phases of free fermions , including a complete classification of such phases that are stable to disorder@xcite . in these phases
the bulk appears , to local probes , as a rather conventional gapped state .
the surface however is gapless unless one of the symmetries protecting the phase is broken ..
Please generate the next two sentences of the article | in contrast our understanding of topological phases of interacting particles is much less complete .
the fractional quantum hall effect has inspired much work on phases with topological order@xcite . |
6,208 | Suppose that you have an abstract for a scientific paper: the high - energy transient explorer ( hete-2 ) , launched in october 2000 , is a satellite experiment dedicated to the study of @xmath0-ray bursts in a very wide energy range from soft x - ray to @xmath0-ray wavelengths . the intermediate x - ray range ( 2 - 30 kev ) is covered by the wide - field x - ray monitor _ wxm _ , a coded aperture imager . in this article , an algorithm for reconstructing the positions of @xmath0-ray bursts
is described , which is capable of correcting systematic aberrations to approximately @xmath1 throughout the field of view .
functionality and performance of this algorithm have been validated using data from monte carlo simulations as well as from astrometric observations of the x - ray source _
scorpius x-1_. epsf , x - ray astronomy , coded - mask imaging , @xmath0-ray bursts 95.55.ka,98.70.rz,95.75.mn .
And you have already written the first three sentences of the full article: although the number of detected @xmath0-ray bursts has increased tremendously due to the batse instrument on board the compton @xmath0-ray observatory @xcite , unique identifications and quick follow - up observations of the celestial object that harbours the burst site are rare .
this issue has been successfully addressed by the bepposax satellite , that monitors a large fraction of the sky ( @xmath2 ) in the intermediate x - ray range @xcite and is able to derive burst localisations with an accuracy of @xmath3 . with such improved localisations ,
the beppo - sax team has succeeded in detecting x - ray afterglows @xcite , by which valuable insight into the emission mechanism was gained ..
Please generate the next two sentences of the article | finding @xmath0-ray burst counterparts and performing spectroscopy at wavelengths other than the @xmath0-ray band during the active phase of a burst as well as providing good localisations for follow - up observations is the basic scientific motivation of the hete-2 mission .
this publication is structured as follows : after a brief description of hete-2 s instrumentation in section [ cont : instruments ] , the position reconstruction algorithm is outlined in section [ cont : algorithm ] . |
6,209 | Suppose that you have an abstract for a scientific paper: transformational optics allow for a markedly enhanced control of the electromagnetic wave trajectories within metamaterials with interesting applications ranging from perfect lenses to invisibility cloaks , carpets , concentrators and rotators . here
, we present a review of curved anisotropic heterogeneous meta - surfaces designed using the tool of transformational plasmonics , in order to achieve a similar control for surface plasmon polaritons in cylindrical and conical carpets , as well as cylindrical cloaks , concentrators and rotators of a non - convex cross - section .
finally , we provide an asymptotic form of the geometric potential for surface plasmon polaritons on such surfaces in the limit of small curvature .
transformational optics , surface plasmon polariton , carpet , cloak , concentrator , rotator .
And you have already written the first three sentences of the full article: it has been known since the advent of mathematical optics @xcite that lenses with certain curvature and/or a spatially varying refractive index allow for focussed images .
indeed , the simplest example of a convergent lens is a curved piece of silica which bends light according to the snell - descartes laws of refraction at curved air / glass interface .
however , such a lens is necessarily of a convex shape . on the contrary.
Please generate the next two sentences of the article | , a medium with a continuously changing refractive index can act as a flat convergent lens : gradient - index optics is indeed the branch of optics covering optical effects produced by a gradual variation of the refractive index of a material with the famous paradigm of the maxwell fisheye , first published by james clerck maxwell in 1854 under the pseudonym of charles anthony swainson @xcite , but however still of current interest @xcite .
a continuously refracting index can also create optical illusions known as mirages : in the desert , these are due to the variation of refractive index between the hot , less dense air at the surface of the road , and the denser cool air above it . |
6,210 | Suppose that you have an abstract for a scientific paper: several doped semiconductors , in contrast to heavily - doped silicon and germanium , host extremely mobile carriers , which give rise to quantum oscillations detectable in relatively low magnetic fields .
the small fermi energy in these dilute metals quantifies the depth of the fermi sea .
when the carrier density exceeds a threshold , accessible thanks to the long bohr radius of the parent insulator , the local seafloor is carved by distant dopants . in such conditions , with a random distribution of dopants , the probability of finding an island or a trench depends on on the effective bohr radius , a@xmath0 and the carrier density , n. this picture yields an expression for electron mobility with a random distribution of dopants : @xmath1(a@xmath2 n@xmath3 , in reasonable agreement with the magnitude and concentration dependence of the low - temperature mobility in three dilute metals whose insulating parents are a wide - gap ( srtio@xmath4 ) , a narrow - gap ( pbte ) and a `` zero''-gap ( tlbisse ) semiconductor . .
And you have already written the first three sentences of the full article: in an outreach paper written in the heyday of elemental fermiology , mackintosh remarked that while `` few people would define a metal as a ` solid with a fermi surface ' , this may nevertheless be the most meaningful definition of a metal.''@xcite . in opposition to a metal
, a semiconductor can be defined as a solid deprived of a fermi surface . doping a semiconductor@xcite ,
can eventually turn it to to metal ..
Please generate the next two sentences of the article | this metal - insulator transition@xcite has been a central issue of the condensed - matter physics during the second half of the twentieth century .
the most - explored system has been silicon doped with phosphorus , its immediate neighbor to the right in the periodical table . |
6,211 | Suppose that you have an abstract for a scientific paper: we establish global existence and uniqueness of the dynamics of classical electromagnetism with extended , rigid charges and fields which need not to be square integrable .
we consider also a modified theory of electromagnetism where no self - fields occur . that theory and our results are crucial for approaching the as yet unsolved problem of the general existence of dynamics of wheeler feynman electromagnetism , which we shall address in the follow up paper . +
* keywords : * maxwell - lorentz equations , wheeler - feynman equations , absorber electrodynamics , radiation damping , self - interaction , infinite energy solutions , weighted function spaces . +
* acknowledgments : * the authors want to thank martin kolb for his valuable comments .
d .-
a.d . gratefully acknowledges financial support from the _ bayefg _ of the _ freistaat bayern _ and the _ universit bayern e.v .
_ as well as the from the post - doc program of the daad
. 1 .
And you have already written the first three sentences of the full article: we consider the global existence of dynamics of classical electromagnetism for extended rigid charges .
to put our work into proper perspective we shall introduce a number of theories ml , ml - si , mld , wf , and @xmath0 , @xmath1 , and @xmath2 .
the former are theories for point - charges , the latter are the theories modified by smeared out charges , i.e. extended rigid charges indicated by the charge distribution @xmath3 ..
Please generate the next two sentences of the article | it will become clear in a moment , why it is helpful to introduce these notations .
ml stands for maxwell - lorentz electrodynamics - the textbook electromagnetism @xcite . |
6,212 | Suppose that you have an abstract for a scientific paper: we investigate the classical stability of schwarzschild - ads black hole in a massive gravity theory of the einstein - weyl gravity .
it turns out that the linearized einstein tensor perturbations exhibit unstable modes featuring the gregory - laflamme instability of five - dimensional ads black string , in contrast to the stable schwarzschild - ads black hole in einstein gravity .
we point out that the instability of the black hole in the einstein - weyl gravity arises from the massiveness but not a feature of fourth - order derivative theory giving ghost states .
+ yun soo myung + institute of basic sciences and department of computer simulation , inje university gimhae 621 - 749 , korea + pacs numbers : 04.70.bw , 04.50.kd .
And you have already written the first three sentences of the full article: recently , babichev and fabbri @xcite have shown that the massive linearized equation around the schwarzschild black hole in both de rham , gabadadze , and tolley ( drgt ) theory @xcite and its bigravity extension @xcite gives rise to an instability of @xmath0-mode ( spherically symmetric mode ) with @xmath1 the spheroidal harmonic index .
this was done by comparing it with the four - dimensional linearized equation around the five - dimensional black string where the gregory - laflamme ( gl ) instability was found @xcite .
it turned out that the bimetric black hole is unstable provided a mass of @xmath2 satisfies a bound of @xmath3 with @xmath4 the horizon radius in the metric function @xmath5 ..
Please generate the next two sentences of the article | we note that the limit of @xmath6 recovers the black hole in the drgt theory .
the black hole in the drgt theory is also unstable because @xmath7 satisfies a bound of @xmath8 . |
6,213 | Suppose that you have an abstract for a scientific paper: we present results of a systematic quantum - monte - carlo study for the single - band hubbard model .
thereby we evaluated single - particle spectra ( pes & ipes ) , two - particle spectra ( spin & density correlation functions ) , and the dynamical correlation function of suitably defined diagnostic operators , all as a function of temperature and hole doping .
the results allow to identify different physical regimes .
near half - filling we find an anomalous ` hubbard - i phase ' , where the band structure is , up to some minor modifications , consistent with the hubbard - i predictions . at lower temperatures , where the spin response becomes sharp , additional dispersionless ` bands ' emerge due to the dressing of electrons / holes with spin excitatons .
we present a simple phenomenological fit which reproduces the band structure of the insulator quantitatively .
the fermi surface volume in the low doping phase , as derived from the single - particle spectral function , is not consistent with the luttinger theorem , but qualitatively in agreement with the predictions of the hubbard - i approximation .
the anomalous phase extends up to a hole concentration of @xmath0% , i.e. the underdoped region in the phase diagram of high - t@xmath1 superconductors .
we also investigate the nature of the magnetic ordering transition in the single particle spectra .
we show that the transition to an sdw - like band structure is not accomplished by the formation of any resolvable ` precursor bands ' , but rather by a ( spectroscopically invisible ) band of spin 3/2 quasiparticles .
we discuss implications for the ` remnant fermi surface ' in insulating cuprate compounds and the shadow bands in the doped materials . 2 .
And you have already written the first three sentences of the full article: the 1-band hubbard model on a two - dimensional square lattice has the hamiltonian @xmath2 here , @xmath3 ( @xmath4 ) creates ( annihilates ) an electron with spin @xmath5 in a wannier orbital centered at lattice site @xmath6 .
the particle density at each site is given by @xmath7 .
the first sum for the kinetic energy is restricted to include only the hopping matrix element @xmath8 between next - nearest neighbor sites @xmath9 ..
Please generate the next two sentences of the article | periodic boundary conditions are used throughout the following work .
the second sum describes for @xmath10 an on - site coulomb repulsion between particles of opposite spin that share the same lattice site . in the present work we restrict ourselves to @xmath11 . |
6,214 | Suppose that you have an abstract for a scientific paper: we map the ground - state ensemble of antiferromagnetic ising model of spin-@xmath0 on a triangular lattice to an interface model whose entropic fluctuations are proposed to be described by an effective gaussian free energy , which enables us to calculate the critical exponents of various operators in terms of the stiffness constant of the interface .
monte carlo simulations for the ground - state ensemble utilizing this interfacial representation are performed to study both the dynamical and the static properties of the model .
this method yields more accurate numerical results for the critical exponents . by varying the spin magnitude in the model ,
we find that the model exhibits three phases with a kosterlitz - thouless phase transition at @xmath1 and a locking phase transition at @xmath2 .
the phase diagram at finite temperatures is also discussed . .
And you have already written the first three sentences of the full article: over the years it has been found that there exist many two - dimensional classical spin models , discrete and continuous alike , whose ground - state manifolds are macroscopically degenerate and , more interestingly , also exhibit critical behaviours , i.e. , spin - spin correlation functions within the ground - state ensembles decay with distance as power laws .
the classification of universality class for these models has always been a challenging problem@xcite an earlier example of this kind is the antiferromagnetic ising model on the triangular lattice .
the exact solution for this model by stephenson@xcite showed that although this model remains paramagnetic at nonzero temperature , its ground state is critical ..
Please generate the next two sentences of the article | later works by blte _
et al _ revealed yet another remarkable property of the ground - state ensemble of this model , namely , it permits a solid - on - solid ( sos ) representation in which spin fluctuations are subsequently described by the fluctuating interface in the sos model@xcite . |
6,215 | Suppose that you have an abstract for a scientific paper: we use neutron diffraction to study the temperature evolution of the average structure and local lattice distortions in insulating and superconducting potassium iron selenide k@xmath0fe@xmath1se@xmath2 . in the high temperature
paramagnetic state , both materials have a single phase with crystal structure similar to that of the bafe@xmath2as@xmath2 family of iron pnictides .
while the insulating k@xmath0fe@xmath1se@xmath2 forms a @xmath3 iron vacancy ordered block antiferromagnetic ( af ) structure at low - temperature , the superconducting compounds spontaneously phase separate into an insulating part with @xmath3 iron vacancy order and a superconducting phase with chemical composition of k@xmath4fe@xmath5se@xmath2 and bafe@xmath2as@xmath2 structure .
therefore , superconductivity in alkaline iron selenides arises from alkali deficient k@xmath4fe@xmath5se@xmath2 in the matrix of the insulating block af phase . .
And you have already written the first three sentences of the full article: of all the iron - based superconductors @xcite , alkali iron selenides @xmath6fe@xmath1se@xmath2 ( @xmath7 k , rb , cs , tl ) @xcite are unique in that superconductivity in this class of materials always coexists with a static long - range antiferromagnetic ( af ) order with a large moment and high n@xmath8el temperature @xcite .
this is in contrast to iron pnictide superconductors @xcite where optimal superconductivity arises from the suppression of the static af order in their nonsuperconducting parent compounds @xcite .
an attempt to understand the coexisting static af order and superconductivity in alkali iron selenides @xcite has produced two proposed scenarios . in the first , superconductivity is believed to coexist microscopically with the static af order @xcite ..
Please generate the next two sentences of the article | however , the af order in @xmath6fe@xmath1se@xmath2 forms a @xmath3 block af structure with an ordered moment of @xmath93.3 @xmath10 per fe as shown in fig .
1(a ) @xcite , making it unclear how superconductivity can survive such a large magnetic field background arising from the ordered moments @xcite . |
6,216 | Suppose that you have an abstract for a scientific paper: in semi - inclusive dis of polarized leptons on a transversely polarized target eight azimuthal modulations appear in the cross - section . within qcd parton model four azimuthal asymmetries
can be interpreted at leading order , two of them being the already measured collins and sivers asymmetries .
the other two leading twist asymmetries , related to different transverse momentum dependent quark distribution functions , and also additional four asymmetries which can be interpreted as twist - three contributions have been measured for the first time at compass , using a 160 gev / c longitudinally polarized ( @xmath0 ) muon beam and a transversely polarized @xmath1 target .
we present here the preliminary results from the 2002 - 2004 data . .
And you have already written the first three sentences of the full article: during last few years many exciting experimental results and theory development are obtained in sidis on the transversely polarized target . up to now
only the measurements @xcite of sivers and collins asymmetries were performed by hermes and compass collaborations and together with data from belle @xcite they allow a first extraction the transversity and sivers transverse momentum dependent ( tmd ) distribution functions ( dfs ) and collins fragmentation function ( ff ) .
in addition to these , the general expression of sidis cross section @xcite contains six more target transverse polarization dependent azimuthal asymmetries . here.
Please generate the next two sentences of the article | we present the preliminary results on these asymmetries for the first time measured by compass from the 2002 - 2004 data . in the following the notations of ref .
@xcite are used . |
6,217 | Suppose that you have an abstract for a scientific paper: we demonstrate , that bose - einstein condensate can escape from the trap , formed of combined linear periodic ( optical lattice ) and parabolic potentials , and the escaping mechanism is similar to hawking radiation from black hole .
the low - amplitude bright - bright soliton in two - component bose - einstein condensate ( where chemical potentials of the bec first and second components are located nearby the opposite edges of the first band of the optical lattice spectrum ) serves as an analogue of particle - antiparticle pair in hawking radiation .
it is shown that parabolic potential , being applied to such two - component bec , leads to spatial separation of its components : bec component with chemical potential located in semi - infinite gap exerts the periodical oscillations , while the bec component , whose chemical potential is in the first finite gap , escapes from the trap ( due to negative effective mass of gap soliton ) . we also propose a method for the creation of such bright - bright soliton transferring of atoms from one bec component to another by spatially periodic linear coupling term . .
And you have already written the first three sentences of the full article: hawking radiation is the remarkable property of black hole : it occurs due to creation of a particle - antiparticle pair nearby the black hole edge @xcite .
if one of the pair constituents crosses the event horizon , it never returns , thus giving rise to the emission from the black hole , which in its turn leads to decreasing of black hole energy and mass ( for review see , e.g. , ref.@xcite ) .
nevertheless , the main difficulty in the experimental confirmation of hawking radiation is the big mass of known black holes in universe , and , hence , weak intensity of hawking radiation ..
Please generate the next two sentences of the article | that is why the reproducing of black holes in laboratory conditions are of great interest .
from one side , small artificial black holes can be created in large hadron collider @xcite . from the other side , |
6,218 | Suppose that you have an abstract for a scientific paper: quaternion analysis of time dependent maxwell s equations in presence of electric and magnetic charges has been developed and the solutions for the classical problem of moving charges ( electric and magnetic ) are obtained in unique , simple and consistent manner .
@xmath0department of physics + govt .
p. g. college + pithoragarh -(ua ) , india @xmath1department of physics + kumaun university + s. s. j. campus + almora-263601 ( ua ) , india email:-@[email protected] + @[email protected] + @xmath1 [email protected] . .
And you have already written the first three sentences of the full article: it is believed that in spite of the recent potential importance of magnetic monopoles@xcite,@xcite,@xcite and dyons @xcite towards the quark confinement problem @xcite of quantum choromodynamics , possible magnetic condensation of vacuum @xcite , cp - violation @xcite , their role as catalyst in proton decay @xcite and the current grand unified theories @xcite , the formalism necessary to describe them has been clumsy and manifestly non - covariant .
keeping in view the potential importance of monopoles and the results of witten @xcite that monopoles are necessarily dyons , we @xcite have also constructed a self - consistent co - variant theory of generalized electromagnetic fields associated with dyons each carrying the generalized charge as complex quantity with its real and imaginary part as electric and magnetic constituents . on the other hand quaternions
were invented by hamilton @xcite to extend the theory of complex numbers to three dimensions ..
Please generate the next two sentences of the article | maxwell s equations of electromagnetism were rewritten in terms of quaternions @xcite .
finklestein et al @xcite developed the quaternionic quantum mechanics and adler @xcite described the theory of the algebraic structure of quantum choromodynamics for strong interactions . |
6,219 | Suppose that you have an abstract for a scientific paper: we consider the problem of detecting communities or modules in networks , groups of vertices with a higher - than - average density of edges connecting them .
previous work indicates that a robust approach to this problem is the maximization of the benefit function known as `` modularity '' over possible divisions of a network .
here we show that this maximization process can be written in terms of the eigenspectrum of a matrix we call the modularity matrix , which plays a role in community detection similar to that played by the graph laplacian in graph partitioning calculations .
this result leads us to a number of possible algorithms for detecting community structure , as well as several other results , including a spectral measure of bipartite structure in networks and a new centrality measure that identifies those vertices that occupy central positions within the communities to which they belong .
the algorithms and measures proposed are illustrated with applications to a variety of real - world complex networks . .
And you have already written the first three sentences of the full article: networks have attracted considerable recent attention in physics and other fields as a foundation for the mathematical representation of a variety of complex systems , including biological and social systems , the internet , the worldwide web , and many others @xcite .
a common feature of many networks is `` community structure , '' the tendency for vertices to divide into groups , with dense connections within groups and only sparser connections between them @xcite .
social networks @xcite , biochemical networks @xcite , and information networks such as the web @xcite , have all been shown to possess strong community structure , a finding that has substantial practical implications for our understanding of the systems these networks represent ..
Please generate the next two sentences of the article | communities are of interest because they often correspond to functional units such as cycles or pathways in metabolic networks @xcite or collections of pages on a single topic on the web @xcite , but their influence reaches further than this .
a number of recent results suggest that networks can have properties at the community level that are quite different from their properties at the level of the entire network , so that analyses that focus on whole networks and ignore community structure may miss many interesting features . |
6,220 | Suppose that you have an abstract for a scientific paper: we discuss instanton fermionic zero modes in the heterotic @xmath0 modification of the cp(1 ) sigma model in two dimensions . by calculating its chiral anomaly
we prove that the number of fermionic zero modes is same as in the standard @xmath1 cp(1 ) case , and determine their explicit form . .
And you have already written the first three sentences of the full article: it has been studied years ago that the supersymmetric generalizations of the bosonic cp(n-1 ) sigma model is automatically an @xmath2 supersymmetric theory by the virtue of that the target space cp(n-1 ) is a khler manifold @xcite .
recently edalati and tong suggested and built an @xmath3 cp(n-1 ) heterotic sigma model by study of the low - energy dynamics of vortex strings in @xmath4 four - dimensional gauge theories@xcite .
later shifman and yung formulated a geometric representation for this heterotic model with the cp(n-1 ) target space for bosonic fields and an extra right - handed fermion which couples to the fermion fields of the @xmath5 cp(n-1 ) model@xcite , and thus breaks the supersymmetry to @xmath3 . in this paper , we follow the geometric formulation to discuss the fermionic zero modes of @xmath3 heterotic cp(1 ) sigma model in the instanton background ..
Please generate the next two sentences of the article | nontrivial homotopy group structure of target space cp(1 ) allows for the bosonic instanton background of the form of a holomorphic function @xmath6 , where @xmath7 and @xmath8 are instanton size and center respectively . under such background
, the fermionic zero modes can be obtained by acting supercharges and superconformal charges to the instanton solution . since the heterotic deformation of the standard cp(1 ) sigma model only preserves half of four original supercharges , the supersymmetries and superconformal symmetries are partly broken . |
6,221 | Suppose that you have an abstract for a scientific paper: are there any degrees of freedom on the black hole horizon ? using the ` membrane paradigm ' we can reproduce coarse - grained physics outside the hole by assuming a fictitious membrane just outside the horizon . but to solve the information puzzle we need ` real ' degrees of freedom at the horizon , which can modify hawking s evolution of quantum modes .
we argue that recent results on gravitational microstates imply a set of real degrees of freedom just outside the horizon ; the state of the hole is a linear combination of rapidly oscillating gravitational solutions with support concentrated just outside the horizon radius .
the collective behavior of these microstate solutions may give a realization of the membrane paradigm , with the fictitious membrane now replaced by real , explicit degrees of freedom .
epsf = = = = = = = = ============= == = = membrane paradigm realized ?
+ + department of physics , + the ohio state university , + columbus , oh 43210 , usa + .2 in [email protected] 1.0 true in a longstanding puzzle in quantum gravity is the following : is there anything at the black hole horizon ?
there are many reasons to take the horizon seriously as a place where ` physics happens ' .
the bekenstein entropy @xmath0 of the hole is proportional to the area of the horizon @xcite .
this suggests that we attach one ` bit ' of information to each planck area of the horizon , and perhaps quantize the horizon area to give an integral number of bits @xcite . in loop quantum gravity
the entropy arises from spin degrees of freedom on links that intersect the horizon @xcite . in the schwarzschild
coordinate frame , all matter that ever fell towards the horizon appears to be frozen forever just outside the horizon .
this picture was concretized in the ` membrane paradigm ' @xcite , where one puts an artificial cutoff surface just outside the horizon , and finds boundary conditions at this surface which will reproduce correct mechanical and thermal effects in....
And you have already written the first three sentences of the full article: this work was supported in part by doe grant de - fg02 - 91er-40690 .
j. d. bekenstein , phys .
d * 7 * , 2333 ( 1973 ) . j. d. bekenstein , lett ..
Please generate the next two sentences of the article | nuovo cim . * 11 * , 467 ( 1974 ) . c. rovelli and l. smolin , nucl .
b * 442 * , 593 ( 1995 ) [ erratum - ibid . |
6,222 | Suppose that you have an abstract for a scientific paper: polymer stretching in random smooth flows is investigated within the framework of the fene dumbbell model .
the advecting flow is gaussian and short - correlated in time .
the stationary probability density function of polymer extension is derived exactly . the characteristic time needed for the system to attain the stationary regime
is computed as a function of the weissenberg number and the maximum length of polymers . the transient relaxation to the stationary regime
is predicted to be exceptionally slow in the proximity of the coil stretch transition . .
And you have already written the first three sentences of the full article: the ability of polymers to considerably change the large - scale statistics of the advecting flow has important practical applications , drag reduction being one of the most relevant ones ( see * ? ? ?
polymers affect the dynamics of the advecting velocity field only if they are highly elongated . understanding how a single polymer chain is stretched by a random flow
is thus the first issue to address in the study of hydrodynamical properties of polymer solutions . at equilibrium ,.
Please generate the next two sentences of the article | the radial shape of coiled polymers is spherical due to their entropy . when placed in a non - homogeneous flow ,
polymers are deformed and stretched by the gradients of the velocity . |
6,223 | Suppose that you have an abstract for a scientific paper: the motion of a contact line is examined , and comparisons drawn , for a variety of models proposed in the literature . pressure and stress
behaviours at the contact line are examined in the prototype system of quasistatic spreading of a thin two - dimensional droplet on a planar substrate .
the models analysed include three disjoining pressure models based on van der waals interactions , a model introduced for polar fluids , and a liquid - gas diffuse - interface model ; navier - slip and two nonlinear slip models are investigated , with three microscopic contact angle boundary conditions imposed ( two of these contact angle conditions having a contact line velocity dependence ) ; and the interface formation model is also considered . in certain parameter regimes
it is shown that all of the models predict the same quasistatic droplet spreading behaviour . _
keywords : _ contact line , slip , diffuse - interface , precursor film , disjoining pressure , interface formation . .
And you have already written the first three sentences of the full article: immiscible fluids and non - porous solids occur abundantly in both nature and industry .
the location at which two such fluids and a solid meet is termed a contact line , and the modelling of moving contact lines is consequently of central importance to the understanding of problems as diverse as how insects walk on water and the wetting properties of plant leaves to coating , inkjet printing , and oil recovery for reviews , see e.g. @xcite .
the main focus of this work is to compare a number of prevalent models proposed to resolve the _ moving contact line problem _ in the prototype system of quasistatic spreading of a thin two - dimensional droplet on a planar substrate ..
Please generate the next two sentences of the article | two early papers sparked interest in the moving contact line problem .
the first by moffatt in 1964 @xcite considered the conceptually simple problem of a wedge of viscous fluid in contact with an inviscid fluid ( the interface kept flat ostensibly by the action of gravity ) , and also in contact with a solid substate moving with a constant velocity @xmath0 . |
6,224 | Suppose that you have an abstract for a scientific paper: the 8.7s x ray pulsar 4u0142 + 61 was monitored by _
beppo_sax between january 1997 and february 1998 .
this source belongs to the rapidly growing class of anomalous " x ray pulsars ( axps ) which have pulse periods in the 612s range and no plausible optical , infrared or radio counterparts .
the _
beppo_sax periods measurements show that 4u0142 + 61 continues its spin down at a nearly constant rate of p@xmath02@xmath110@xmath2 s s@xmath3 . the 0.510 kev pulse shape is double peaked .
the phase averaged spectrum can be described by a steep absorbed power
law ( @xmath4 @xmath0 4 ) plus a blackbody with @xmath5 @xmath0 0.4 kev .
4u0142 + 61 was also detected serendipitously in a march 1996 rxte observation pointed towards the nearby 1455s x ray pulsar rxj0146.9 + 6121 .
the timing analysis results are reported for this observation and the spin history of 4u0142 + 61 since 1979 is discussed . .
And you have already written the first three sentences of the full article: the properties of 4u0142 + 61 ( white et al .
1987 ) remained puzzling for a long time , owing to confusion with a nearby pulsating and transient be / neutron star system rxj0146.9 + 6121 ( motch et al . 1991 ; mereghetti et al . 1993 ) .
the 110 kev spectrum is extremely soft ( power law photon index of @xmath6 , white et al ..
Please generate the next two sentences of the article | 1987 ) and led to the initial classification of 4u0142 + 61 as a possible black hole candidate .
asca observations provide evidence for a @xmath7 kev blackbody component contributing @xmath8% of the 0.510 kev band x ray flux ( white et al . |
6,225 | Suppose that you have an abstract for a scientific paper: we reexamine critically the chiral expansion for the baryon magnetic moments including the contributions from loops which involve intermediate octet and decuplet baryons .
we find that , contrary to some claims , the nonanalytic loop contributions of orders @xmath0 and @xmath1 are of the same general size because of large coupling factors for the latter , and that the decuplet contributions are as large as the octet contributions and must be included in a consistent calculation .
there is no clear evidence of the convergence of the chiral series .
the adequacy of the theory will not be established until dynamical models are able to calculate the contributions from the counterterms that largely hide the loop effects in fits to the data . .
And you have already written the first three sentences of the full article: chiral perturbation theory ( chpt ) has been a very useful approach to the theory of the low momentum processes involving mesons and baryons , and has been used in various attempts to explain the baryon magnetic moments .
all the moments in the baryon octet except that of the @xmath2 have been measured .
the @xmath3 transition moment @xmath4 is also known . at the su(3)-symmetric tree level @xcite.
Please generate the next two sentences of the article | , chpt parameterizes these eight measured quantities terms of the two parameters @xmath5 and @xmath6 in the effective lagrangian @xmath7 ) \ , \ ] ] and is able to fit them with an average error of about 0.24 nuclear magnetons @xmath8 . in this expression
, @xmath9 is the usual representation for the baryon - octet in flavor - space , @xmath10 is the quark matrix , @xmath11 is the nucleon mass , and @xmath12 is the electromagnetic field . |
6,226 | Suppose that you have an abstract for a scientific paper: binary stars are predicted to have an important role in the evolution of globular clusters , so we obtained binary fractions for 35 globular clusters that were imaged in the f606w and f814w with the acs on the hubble space telescope . when compared to the values of prior efforts @xcite , we find significant discrepancies , despite each group correcting for contamination effects and having performed the appropriate reliability tests .
the most reliable binary fractions are obtained when restricting the binary fraction to @xmath0 .
our analysis indicates that the range of the binary fractions is nearly an order of magnitude for the lowest dynamical ages , suggesting that there is a broad distribution in the binary fraction at globular cluster formation .
dynamical effects also appears to decrease the core binary fractions by a factor of two over a hubble time , but this is a weak relationship .
we confirm a correlation from previous work that the binary fraction within the core radius decreases with cluster age , indicating that younger clusters formed with higher binary fractions .
the strong radial gradient in the binary fraction with cluster radius appears to be a consequence of dynamical interactions .
it is often not present in dynamically young clusters but nearly always present in dynamically old clusters . .
And you have already written the first three sentences of the full article: globular clusters have dynamical properties that distinguish them from other stellar systems and allow one to test dynamical models .
they can be very long - lived , with typical ages for galactic globular clusters of 7 - 13 gyr @xcite , yet they are dynamically active in that their dynamical relaxation times are significantly less than a hubble time @xcite . for the well - observed galactic globular clusters ,
the ratio of the age to the relaxation time ( at the half - light radius ) lies in the range 2 - 40 ( a median of 7 - 8 ) , representing clusters that display modest dynamical evolution to those that have undergone core collapse ..
Please generate the next two sentences of the article | binary stars are expected to play a central role in the dynamical evolution of globular clusters through the process of binary burning . in this process
, the dynamical interactions of binaries with other stars or binaries both hardens the binary and adds kinetic energy to the interacting star ( other binary ) , thereby slowing the contraction of the cluster , especially in the core region . |
6,227 | Suppose that you have an abstract for a scientific paper: the first comprehensive analyses of planck data reveal that the cosmological model with dark energy and cold dark matter can satisfactorily explain the essential physical features of the expanding universe . however , the inability to simultaneously fit large and small scale tt power spectrum , scalar power index smaller than one and the observations of the violation of the isotropy found by few statistical indicators of the cmb , urge theorists to search for explanations .
we show that the model of the einstein - cartan cosmology with clustered dark matter halos and their corresponding clustered angular momenta coupled to torsion , can account for small scale - large scale discrepancy and larger peculiar velocities ( bulk flows ) for galaxy clusters .
the nonvanishing total angular momentum ( torsion ) of the universe enters as a negative effective density term in the einstein - cartan equations causing partial cancellation of the mass density .
the integrated sachs - wolfe contribution of the einstein - cartan model is negative , thus it can provide partial cancellation of the large scale power of the tt cmb spectrum .
the observed violation of the isotropy appears as a natural ingredient of the einstein - cartan model caused by the spin densities of light majorana neutrinos in the early stage of the evolution of the universe and bound to the lepton cp violation and matter - antimatter asymmetry .
+ pacs numbers : 98.80.es ; 12.10.dm ; 04.60.-m .
And you have already written the first three sentences of the full article: although the presence of dark matter and dark energy is justified by all cosmological observations , their identification and properties are still far from being established .
the measurements of the fluctuations of the cmb are in this respect escpecially valuable because of the wealth and accurate information that can be extracted from them .
the most recent disclosed results of the planck mission contain issues like : the temperature power spectrum , gravitational lensing or integrated sachs - wolfe effect , up to sunyaev - zeldovich cluster counts , isotropy , nongaussianity or cosmic infrared background ..
Please generate the next two sentences of the article | it seems that the old , unexpected features , beyond the @xmath0 + inflation model , persist in data and are even more highlighted : 1 .
large scale temperature power spectrum much lower than the @xmath0 prediction , not limited only to low quadrupole @xcite but to almost all multipole moments @xmath1 ( see fig . |
6,228 | Suppose that you have an abstract for a scientific paper: we present broad - band ( @xmath0 and @xmath1 ) and narrow - band ( + [ n ii ] and ) images of the circumnuclear starburst rings in two nearby spiral galaxies , ngc 1512 and ngc 5248 , obtained with the wfpc2 and nicmos cameras on _ hst_. combined with previously published ultraviolet ( uv ) images at 2300 , these data provide a particularly wide wavelength range with which to study the properties of the stellar populations , the gas , and the dust in the rings .
the young star clusters and the line - emitting gas have different spatial distributions , with some large ( 50-pc scale ) line - emitting regions that have little associated continuum emission , but a equivalent width indicating a few - myr - old embedded stellar population .
the observed / intensity ratios suggest the gas is mixed with dust , making it effective at obscuring some of the young clusters .
we identify the major ( about 500 in each galaxy ) compact continuum sources ( super star clusters and individual stars ) and analyze their spectral energy distributions ( seds ) from 0.2 @xmath2 m to 1.6 @xmath2 m by fitting them with a grid of spectral synthesis models with a range of ages and dust extinction .
most of the visible clusters are only mildly reddened , with @xmath3 to 1 mag , suggesting that the processes that clear out the gas and dust of the stellar birth clouds are efficient and fast .
the patchiness of the dust distribution makes it difficult to reliably estimate the star formation rate , based on uv continuum slope or hydrogen emission - line ratios , in starbursts such as these .
the cluster seds are consistent with a range in ages , from 1 myr to 300 myr , but with only a minority older than a few tens of myr .
we point out an age bias , the result of the steep luminosity function of the clusters combined with the fading of clusters as they age , which causes young clusters to be over - represented at any luminosity . accounting for this bias , the fraction of old clusters is consistent with continuous....
And you have already written the first three sentences of the full article: galaxy imaging with the _ hubble space telescope _ ( _ hst _ ) has revealed a population of compact , young star clusters in a variety of starburst environments ( holtzman et al .
1992 ; benedict et al . 1993 ; whitmore et al . 1993 ; conti & vacca 1994 ; hunter , oconnell , & gallagher 1994 ; oconnell , gallagher , & hunter 1994 ; oconnell et al .
1995 ; whitmore & schweizer 1995 ; meurer et al . 1995 ; barth et al.1995 ; maoz et al . 1996 ; holtzman et al . 1996.
Please generate the next two sentences of the article | ; miller et al .
1997 ; stiavelli et al . |
6,229 | Suppose that you have an abstract for a scientific paper: the einstein equations are completely integrated in the presence of two ( incoming and outgoing ) streams of null dust , under the assumptions of spherical symmetry and staticity .
the solution is also written in double null and in radiation coordinates and it is reinterpreted as an anisotropic fluid .
interior matching with a static fluid and exterior matching with the vaidya solution along null hypersurfaces is discussed .
the connection with two - dimensional dilaton gravity is established . .
And you have already written the first three sentences of the full article: null dust represents the high frequency ( geometrical optics ) approximation to the unidirectional radial flow of unpolarized radiation .
this is a reasonable approximation whenever the wavelength of the radiation is negligible compared to the curvature radius of the background .
various exact solutions of the einstein field equations were found in the presence of pure null dust ( for reviews see @xcite , and more recently @xcite and @xcite ) . in some scenarios.
Please generate the next two sentences of the article | even gravitation behaves as null dust .
price @xcite has shown that a collapsing spheroid radiates away all of its initial characteristics excepting its mass , angular momentum and charge . |
6,230 | Suppose that you have an abstract for a scientific paper: the fano line profiles , originally discovered in the context of photoionization , have been found to occur in a large class of systems like resonators , metamaterials , plasmonics .
we demonstrate the existence of such resonances in cavity optomechanics by identifying the interfering contributions to the fields generated at antistokes and stokes frequencies .
unlike the atomic systems , the optomechanical systems provide great flexibility as the width of the resonance is controlled by the coupling field .
we further show how the double cavities coupled by a single optomechanical mirror can lead to the splitting of the fano resonance and how the second cavity can be used to tune the fano resonances .
the fano resonances are quite sensitive to the decay parameters associated with cavities and the mechanical mirror . such resonances can be studied by both pump probe experiments as well as the spectrum of the quantum fluctuations in the output fields . .
And you have already written the first three sentences of the full article: the fano line shapes @xcite have played an important role in our understanding of the photoelectron spectra @xcite in atomic physics and more recently in the field of plasmonics @xcite . in atomic systems
the interference minimum in the fano line shape has been extensively used in extracting information on the relative strengths of the different decay channels which are responsible for interference effects .
the fano interference has been at the forefront in producing lasing without population inversion @xcite ..
Please generate the next two sentences of the article | the fano line shapes have been considered as a probe of decoherence @xcite .
the fano interference is leading to other remarkable possibilities like the improvement in the efficiency of the heat engines @xcite . in plasmonics , |
6,231 | Suppose that you have an abstract for a scientific paper: given a hyperbolic knot , we prove that the reidemeister torsion of any lift of the holonomy to @xmath0 is invariant under mutation along a conway sphere . .
And you have already written the first three sentences of the full article: let @xmath1 be a hyperbolic knot and @xmath2 a conway sphere .
namely @xmath3 intersects transversally @xmath4 in four points .
we write @xmath5 to denote any of the three involutions in figure [ fig : involutions ] , for @xmath6 ..
Please generate the next two sentences of the article | the knot @xmath7 obtained by cutting along @xmath3 and gluing again after composing with @xmath8 is called the mutant knot .
we are interested in comparing invariants of @xmath4 and @xmath9 , thus we may assume that , if @xmath10 denotes the knot exterior , then the surface @xmath11 is essential in @xmath12 . |
6,232 | Suppose that you have an abstract for a scientific paper: in this paper , we consider the minimal entropy of qubit states transmitted through two uses of a noisy quantum channel , which is modeled by the action of a completely positive trace - preserving ( or stochastic ) map .
we provide strong support for the conjecture that this minimal entropy is additive , namely that the minimum entropy can be achieved when product states are transmitted .
explicitly , we prove that for a tensor product of two unital stochastic maps on qubit states , using an entanglement that involves only states which emerge with minimal entropy can not decrease the entropy below the minimum achievable using product states .
we give a separate argument , based on the geometry of the image of the set of density matrices under stochastic maps , which suggests that the minimal entropy conjecture holds for non - unital as well as for unital maps .
we also show that the maximal norm of the output states is multiplicative for most product maps on @xmath0-qubit states , including all those for which at least one map is unital . for the class of _ unital _ channels on @xmath1
, we show that additivity of minimal entropy implies that the holevo capacity of the channel is _ additive _ over two inputs , achievable with orthogonal states , and equal to the shannon capacity .
this implies that superadditivity of the capacity is possible only for non - unital channels . _
key words : _ entangled state ; minimal entropy ; qubit ; stochastic map . .
And you have already written the first three sentences of the full article: when a pure state , represented by a density matrix @xmath2 , is transmitted along a noisy channel , it is mapped into a mixed state @xmath3 .
the entropy of the initial pure state is necessarily zero , i.e. , @xmath4 since @xmath5 and so the only eigenvalues of @xmath2 are @xmath6 and @xmath7 .
however , the entropy @xmath8 $ ] of the mixed state which emerges need not be zero ..
Please generate the next two sentences of the article | one seeks states @xmath2 which minimize the effect of the noise in the sense of minimizing the entropy @xmath8 $ ] of the state that emerges from the channel .
there are a number of reasons for studying such states , most notably the connection between minimizing entropy and maximizing channel capacity , which will be discussed in section [ subsect : prelim.cap ] . however , in this paper we focus attention on the entropy . the noise , which results from interactions between the states in a hilbert space @xmath9 and the environment , is represented by the action of a completely positive , trace - preserving map @xmath10 on the trace class operators in @xmath11 . |
6,233 | Suppose that you have an abstract for a scientific paper: for group - living animals , reaching consensus to stay cohesive is crucial for their fitness , particularly when collective motion starts and stops .
understanding the decision - making at individual and collective levels upon sudden disturbances is central in the study of collective animal behavior , and concerns the broader question of how information is distributed and evaluated in groups . despite the relevance of the problem , well - controlled experimental studies that quantify the collective response of groups facing disruptive events are lacking .
here we study the behavior of groups of uninformed individuals subject to the departure and stop of a trained conspecific .
we find that the groups reach an effective consensus : either all uninformed individuals follow the trained one ( collective motion occurs ) or none does . combining experiments and a simple mathematical model we show that the observed phenomena results from the interplay between simple mimetic rules and the characteristic duration of the stimulus , here , the time the trained individual is moving away .
the proposed mechanism strongly depends on group size , as observed in the experiments , and though group splitting can occur , the most likely outcome is always a coherent collective group response ( consensus ) .
the prevalence of a consensus is expected even if the groups of naives face conflicting information , e.g. if groups contain two subgroups of trained individuals , one trained to stay and one trained to leave .
our results indicate that collective decision - making and consensus in ( small ) animal groups are likely to be self - organized phenomena that do not involve concertation or even communication among the group members . .
And you have already written the first three sentences of the full article: many gregarious vertebrates are fusion - fission species , with frequent changes in size and composition of groups . in addition , the habitat they live in is generally heterogeneous , such that individuals alone or in groups may have to move among more or less distant areas in order to fulfil their basic vital requirements , e.g. drinking , resting or avoiding pblackators @xcite . even during feeding periods , animals have to search for available food , moving slowly and on short distances between feeding stations or more rapidly and on larger distances to exploit distinct feeding areas @xcite .
thus , groups either resting or feeding with animals motionless or moving slowly are frequently joined by incoming individuals but also submitted to departures of group members @xcite . when faced to multiple choices
, social organisms must reach consensus in order to maintain the cohesion of the group and the advantages linked to it @xcite ..
Please generate the next two sentences of the article | the departure of one or few individuals from static groups as well as stops in moving groups compromise social cohesion @xcite .
this is particularly critical for small groups a scenario that applies to most gregarious animals @xcite despite the popularity and fascination that produce giant bird flocks or fish schools @xcite where group splitting represents a serious pblackatory risk @xcite . |
6,234 | Suppose that you have an abstract for a scientific paper: a simplified version of a classical problem in thermodynamics the adiabatic piston is discussed in the framework of kinetic theory .
we consider the limit of gases whose relaxation time is extremely fast so that the gases contained on the left and right chambers of the piston are always in equilibrium ( that is the molecules are uniformly distributed and their velocities obey the maxwell - boltzmann distribution ) after any collision with the piston . then by using kinetic theory we derive the collision statistics from which we obtain a set of ordinary differential equations for the evolution of the macroscopic observables ( namely the piston average velocity and position , the velocity variance and the temperatures of the two compartments ) .
the dynamics of these equations is compared with simulations of an ideal gas and a microscopic model of gas settled to verify the assumptions used in the derivation .
we show that the equations predict an evolution for the macroscopic variables which catches the basic features of the problem .
the results here presented recover those derived , using a different approach , by gruber , pache and lesne in _
j. stat .
phys .
_ * 108 * , 669 ( 2002 ) and * 112 * , 1177 ( 2003 ) . .
And you have already written the first three sentences of the full article: the so - called _ adiabatic piston _ is a long known problem in classical thermodynamics , which can be stated as follows @xcite .
an isolated cylinder of length @xmath0 , containing a gas , is divided by an adiabatic wall ( no internal degrees of freedom ) , _ the piston _ , into two compartments ( fig .
[ fig:1 ] ) ..
Please generate the next two sentences of the article | the initial condition is prepared in the following way : the piston is kept fixed by a clamp at a given position @xmath1 ; the gases in the left ( @xmath2 ) and right ( @xmath3 ) compartments are in equilibrium defined by their pressure , temperature and volume : @xmath4 . by assuming that the two gases are perfect and composed by @xmath5 molecules with equal masses @xmath6 , the gas state equation @xmath7 holds in both chambers ( where the boltzmann constant is set to unity by rescaling the temperatures ) . being the piston adiabatic , the two subsystems are in equilibrium even if @xmath8 . at @xmath9
the clamp is removed and the piston is free to move without friction with the cylinder . |
6,235 | Suppose that you have an abstract for a scientific paper: two scenarios of possible ion heating due to finite amplitude parallel propagating alfvn waves in the solar atmosphere are investigated using a 1d test particle approach .
1 .
a finite amplitude alfvn wave is instantly introduced into a plasma ( or equivalently , new ions are instantly created ) .
2 .
new ions are constantly created . in both scenarios ,
ions will be picked up by the alfvn wave . in case 1 ,
the wave scatters ions in the transverse direction leading to a randomization ( or heating ) process .
this process is complete when a phase shift of @xmath0 in the ion gyrospeed is produced between particles with characteristic parallel thermal speed and particles with zero parallel speed .
this corresponds to @xmath1 ( @xmath2 is the wavenumber and @xmath3 is the ion thermal speed ) . a ring velocity distribution can be produced for a large wave amplitude .
the process yields a mass - proportional heating in the transverse direction , a temperature anisotropy and a bulk flow along the background magnetic field . in case 2
, continuous ion creation represents a continuing phase shift in the ion gyrospeed leading to heating .
new particles are picked up by the alfvn wave within one ion gyroperiod .
it is speculated that the mechanism may operate in the chromosphere and active regions where transient events may generate finite amplitude alfvn waves . to appear in apj letters may 10 , 2007 . .
And you have already written the first three sentences of the full article: it has been widely speculated that the energy that heats the corona comes from the convective flows in the photosphere .
the energy is somehow transported into the coronal part through the magnetic field .
it is natural to think that alfvn waves channel the energy to the corona ..
Please generate the next two sentences of the article | indeed , these waves have been observed in the solar atmosphere ( ulrich 1996 ) , and are ubiquitous in the extended corona the fast solar wind ( smith et al .
however alfvn waves are difficult to dissipate in collisionless plasmas . |
6,236 | Suppose that you have an abstract for a scientific paper: the brain s activity is characterized by the interaction of a very large number of neurons that are strongly affected by noise .
however , signals often arise at macroscopic scales integrating the effect of many neurons into a reliable pattern of activity . in order to study such large neuronal assemblies ,
one is often led to derive mean - field limits summarizing the effect of the interaction of a large number of neurons into an effective signal .
classical mean - field approaches consider the evolution of a deterministic variable , the mean activity , thus neglecting the stochastic nature of neural behavior . in this article
, we build upon two recent approaches that include correlations and higher order moments in mean - field equations , and study how these stochastic effects influence the solutions of the mean - field equations , both in the limit of an infinite number of neurons and for large yet finite networks .
we introduce a new model , the infinite model , which arises from both equations by a rescaling of the variables and , which is invertible for finite - size networks , and hence , provides equivalent equations to those previously derived models .
the study of this model allows us to understand qualitative behavior of such large - scale networks .
we show that , though the solutions of the deterministic mean - field equation constitute uncorrelated solutions of the new mean - field equations , the stability properties of limit cycles are modified by the presence of correlations , and additional non - trivial behaviors including periodic orbits appear when there were none in the mean field .
the origin of all these behaviors is then explored in finite - size networks where interesting mesoscopic scale effects appear .
this study leads us to show that the infinite - size system appears as a singular limit of the network equations , and for any finite network , the system will differ from the infinite system . [ [ keywords ] ] keywords + + + + + + + + neural mass....
And you have already written the first three sentences of the full article: cortical activity manifests highly complex behaviors which is often strongly characterized by the presence of noise .
reliable responses to specific stimuli often arise at the level of population assemblies ( cortical areas or cortical columns ) featuring a very large number of neuronal cells presenting a highly nonlinear behavior and that are interconnected in a very intricate fashion . understanding
the global behavior of large - scale neural assemblies has been a great endeavor in the past decades ..
Please generate the next two sentences of the article | most models describing the emergent behavior arising from the interaction of neurons in large - scale networks have relied on continuum limits ever since the seminal work of wilson and cowan and amari @xcite .
such models tend to represent the activity of the network through a macroscopic variable , the population - averaged firing rate , that is generally assumed to be deterministic . |
6,237 | Suppose that you have an abstract for a scientific paper: we consider a communication network consisting of nodes and directed edges that connect the nodes .
the network may contain cycles .
the communications are slotted where the duration of each time slot is equal to the maximum propagation delay experienced by the edges .
the edges with negligible delays are allowed to be operated before the other edges in each time slot . for any pair of adjacent edges
@xmath0 and @xmath1 where @xmath2 terminates at node @xmath3 and @xmath1 originates from node @xmath3 , we say @xmath2 _ incurs zero delay _ on @xmath1 if @xmath2 is operated before @xmath1 ; otherwise , we say @xmath2 _ incurs a unit delay _ on @xmath1 . in the classical model ,
every edge incurs a unit delay on every adjacent edge and the cut - set bound is a well - known outer bound on the capacity region . in this paper , we investigate the multimessage multicast network ( mmn ) consisting of independent channels where each channel is associated with a set of edges and each edge may incur zero delay on some other edges .
our result reveals that the capacity region of the mmn with independent channels and zero - delay edges lies within the classical cut - set bound despite a violation of the unit - delay assumption .
multimessage multicast networks , zero - delay edges , independent channels , cut - set bounds .
And you have already written the first three sentences of the full article: paper studies time - slotted communications over networks consisting of nodes and directed edges that connect the nodes , and the networks may contain cycles . each edge receives a symbol from a node and outputs a symbol to a node in each time slot , where the duration of a time slot is set to be the maximum propagation delays experienced by the edges . in practical communication networks ,
propagation delays of different links may vary significantly due to different distances and different transmission medium ( e.g. , optical fiber , air , water , etc . ) across different links .
for example , links with relatively short distances have shorter propagation delays compared to those with relatively long distances , and links established through the optical fiber medium generally experience negligible propagation delays compared to links established through the water medium . in order to characterize the scenario where the propagation delays experienced by some edges are negligible compared to the delays experienced by the other edges.
Please generate the next two sentences of the article | , we allow the edges with negligible delays to be operated before the rest of the edges in each time slot .
since the symbols transmitted on earlier - operated edges may depend on the symbols output from latter - operated edges , we say that an edge @xmath2 terminating at node @xmath3 _ incurs zero delay _ on an edge @xmath1 originating from node @xmath3 if @xmath2 is operated before @xmath1 ; otherwise , we say @xmath2 _ incurs a unit delay _ on @xmath1 . |
6,238 | Suppose that you have an abstract for a scientific paper: we prove that there is a map from bloch s cycle complex to kato s complex of milnor k - theory , which induces a quasi - isomorphism from cycle complex mod @xmath0 to moser s complex of logarithmic de rham witt sheaves .
next we show that the truncation of bloch s cycle complex at @xmath1 is quasi - isomorphic to spiess dualizing complex . in the end , we prove that a weak form of the gersten conjecture implies that sato s dualizing complex is quasi - isomorphic to bloch s complex . .
And you have already written the first three sentences of the full article: using lichtenbaum s weight - two motivic complex @xmath2 ( a two - term complex derived from relative k - theory ) , m. spiess @xcite constructed a complex of tale sheaves @xmath3 ( definition [ definition : spiesscomplex ] ) on arithmetic surfaces @xmath4 over a dedekind domain @xmath5 and used it to prove a duality theorem of constructible sheaves . for @xmath4 over a perfect field @xmath6 of characteristic @xmath7 , t. moser @xcite studied gersten complexes of logarithmic de rham witt sheaves @xmath8 ( [ definition : mosercomplex ] ) and showed that , when @xmath6 is finite , @xmath9 is a dualizing complex for constructible @xmath10-sheaves . for regular semi - stable schemes
@xmath4 over certain dedekind domain @xmath5 ( see condition [ condition * ] ) , k. sato @xcite defined certain dualizing complex @xmath11 ( @xmath12 ) ( definition [ definition : satocomplex ] ) in derived category of tale sheaves and proved a duality theorem for @xmath10-sheaves as well . in more general situations , for instance , schemes over algebraically closed fields , finite fields , local fields and certain dedekind domains , t. geisser @xcite proved that the complex @xmath13 of tale sheaves ( see ( [ definition : blochcomplex ] ) ) is a dualizing complex for constructible sheaves . here
@xmath14 is bloch s cycle complex whose homology defines higher chow groups @xcite . in this paper , we answer the following questions of quasi - isomorphisms of these complexes : for @xmath4 a scheme separated and essentially of finite type over a perfect field @xmath6 of characteristic @xmath7 , and @xmath15 , there is a map @xmath16 which induces a quasi - isomorphism . here.
Please generate the next two sentences of the article | @xmath17 .
let @xmath4 be a surface over a perfect field @xmath6 or a dedekind domain @xmath5 with perfect residue fields . |
6,239 | Suppose that you have an abstract for a scientific paper: this paper presents the set of measurements of ultra - high energy air shower radio emission at frequency 32 mhz in period of 2008 - 2012 .
the showers are selected by geomagnetic and azimuth angles and then by the energy in three intervals : 3@xmath010@xmath1 3@xmath010@xmath2 ev , 3@xmath010@xmath2 6@xmath010@xmath2 ev and 6@xmath010@xmath2 5@xmath010@xmath3 ev . in each energy interval
average lateral distribution function using mathematically averaged data from antennas with different directions are plotted . in the paper , using experimental data the dependence of radio signal averaged amplitude from geomagnetic angle , the shower axis distance and the energy are determined .
depth of maximum of cosmic ray showers xmax for the given energy range is evaluated .
the evaluation is made according qgsjet model calculations and average lateral distribution function shape . .
And you have already written the first three sentences of the full article: one of the techniques to register ultra - high energy extensive air showers ( eas ) is measuring strength of radio pulse by antennas . unlike traditional techniques , including optic measurements of air shower propagation radio technique can operate in any atmospheric condition except during thunderstorm conditions for whole observation period , which dramatically increases effective time of air showers registration .
it is easier to use and much cheaper than other ground detectors in existing air showers array . the yakutsk array measured three components of air shower : the total charged component , the muon component and cherenkov radiation . from these components using average lateral distribution function ( ldf ) the integral characteristics of air shower , the total number of charged particles , the total number of muons and full flux of cherenkov light at the sea level are recovered .
all these shower characteristics are used for further model - free air shower energy estimation as shown in [ 1 ] ..
Please generate the next two sentences of the article | cherenkov light registered at the sea level moreover is used to recover air shower longitudinal distribution and it characteristics , cascade curve and depth of maximum x@xmath4 [ 2][3 ] .
using this , in future is possible to find a relation between the characteristics of the radio emission and characteristics of the eas , including slope of the radio emission ldf with depth of maximum , as shown in [ 4 ] . |
6,240 | Suppose that you have an abstract for a scientific paper: chiral effective field theory predicts a charge symmetry violating ( csb ) amplitude for pion - nucleon scattering .
this mechanism provides a very large contribution also to the csb forward - backward asymmetry in the angular distribution of the reaction @xmath0 .
this contribution was so large that it had a potential to cause a large effect also in csb elastic @xmath1 scattering and to disturb its present understanding .
however , it can be seen that , contrary to pion production , in this case the @xmath2-quark mass difference and electromagnetic contribution to the @xmath3-mass difference tend to cancel causing the total effect in the effective range parameters @xmath4 and @xmath5 to be relatively small . in the lowest order and within the static approximation for the nucleons csb pion - nucleon rescattering does not influence @xmath3 scattering .
= by -1 .
And you have already written the first three sentences of the full article: charge symmetry is a special case of the general flavour symmetry of qcd , which at its simplest distinguishes the proton and the neutron ( or @xmath6 and @xmath7 quarks ) .
it is , of course , trivially broken by the electromagnetic interaction , notably the coulomb force in comparisons of the @xmath8 and @xmath9 systems and by the magnetic interaction in the @xmath3 system .
other well known sources are the @xmath3 mass difference and @xmath10- as well as @xmath11-meson mixing . these in turn may be related to the up- and down - quark mass difference - the microscopic flavour symmetry breaking in qcd ..
Please generate the next two sentences of the article | one might consider remarkable the fact that , although the relative quark mass difference is large ( @xmath12 ) , the symmetry breaking at the observable hadron level is two orders of magnitude smaller . in the mirror system
@xmath8 vs. @xmath9 csb has been studied for many decades @xcite , while its appearance in the @xmath3 system was first seen only a decade ago @xcite as the difference @xmath13 of elastic analyzing powers . |
6,241 | Suppose that you have an abstract for a scientific paper: new x - ray observations from the _ chandra _ and xmm-_newton _ observatories have shown that cooling of the intracluster medium is occurring at rates that are now approaching the star formation rates measured in cd galaxies at the bases of cooling flows .
star formation proceeds in repeated episodes , possibly indicating an intermittent fuel supply . coupled with new evidence for
heating by agn , a new paradigm of self - regulated cooling and star formation in cluster cores is emerging . .
And you have already written the first three sentences of the full article: little has changed in our understanding of star formation in cooling flows since the the topic was last reviewed at the meeting on cooling flows at haifa in 1996 .
however , the nature of the so - called `` cooling flow problem '' has changed dramatically since then .
this controversial problem concerns the deficit between the large cooling rates of the kev gas in the centers of clusters and the much smaller star formation rates observed in central cluster galaxies located at the bases of cooling flows ( fabian 1994 ) ..
Please generate the next two sentences of the article | while the cooling rates based on _ einstein _ and _ rosat _ x - ray observations ( but not asca , see makishima this conference ) were claimed to be tens to hundreds of solar masses per year , the star formation rates are generally between a few to several tens of solar masses per year . in spite of recent detections of molecular gas in cooling flows ( edge 2001 )
, this apparent violation of mass continuity can not be reconciled by a repository of molecular gas clouds or star formation with the local initial mass function in central cluster galaxies . |
6,242 | Suppose that you have an abstract for a scientific paper: the @xmath0 pauli operators attached to a composite qudit in dimension @xmath1 may be mapped to the vectors of the symplectic module @xmath2 ( @xmath3 being the modular ring ) . as a result
, perpendicular vectors correspond to commuting operators , a free cyclic submodule to a maximal commuting set , and disjoint such sets to mutually unbiased bases . for dimensions
@xmath4 , and @xmath5 , the fine structure and the incidence between maximal commuting sets is found to reproduce the projective line over the rings @xmath6 , @xmath7 , @xmath8 , @xmath9 and @xmath10 , respectively . .
And you have already written the first three sentences of the full article: commutation relations of ( generalized ) pauli operators provide a skeleton for mutually unbiased bases , quantum entanglement and other conceptual ( or practical ) issues like quantum computing @xcite .
recently , an extensive study of commuting / non commuting rules has been undertaken , firstly in prime power dimensions @xmath11 of the hilbert space @xcite-@xcite , then in the smallest composite dimension @xmath12 @xcite .
commutation relations of two - qubit operators , and dually the incidence relations between maximal commuting sets of them , have been shown to fit the ( symplectic ) generalized quadrangle of order two , and several projective embeddings have been proposed @xcite . for higher - order pauli operators , the duality between the observables and their maximal commuting sets does not occur and the geometrical space of points / observables may exhibit several lines / sets passing through @xmath13-tuples of distinguished points @xcite . in this communication , one makes use of the maximal ideals of some ring @xmath14 ( possibly different from the modular ring @xmath3 ) as the gears of commutation relations . in particular , the incidence between the twelve lines of the sextit system fits the grid like structure of the projective line @xmath15 over the modular ring @xmath16 . in the higher composite dimensions explored so far @xmath17 , @xmath18 , @xmath19 and @xmath20 ,.
Please generate the next two sentences of the article | the incidence of the maximal commuting sets is found to reproduce the projective line @xmath21 over rings @xmath22 ,
@xmath23 , @xmath24 and @xmath25 , respectively . |
6,243 | Suppose that you have an abstract for a scientific paper: a simple model of an irreversible process is introduced .
the equation of iterations in the model includes a noise generation term .
we study the properties of the system when the noise generation term is a stochastic process ( a random number generator ) or a deterministic process ( a chaotic map ) .
we compare the time series obtained from the above implementations of the model by use of statistical methods ( such as detrended fluctuation analysis ) .
the conclusion is that using statistical methods the two versions of the model are indistinguishable .
the advantage of this observation is that we may calculate the lyapunov exponent for the model . as a result
we obtain an equation relating the dfa exponents ( a statistical measure ) with the lyapunov exponent for such models . on the other hand , typical statistical properties
can also be calculated , as for example the diffusion coefficient for a particle , which movement is defined by the above model .
= by -1 .
And you have already written the first three sentences of the full article: usually deterministic and stochastic analysis are not considered compatible . on one hand
we are often limited to statistical analysis when dealing with experimental time series . on the other hand
a purely stochastic approach to data analysis may lead to an erroneous interpretation about the genesis of the analyzed system . in this work.
Please generate the next two sentences of the article | , we investigate , whether it is possible to substitute the lyapunov exponent with a statistical measure , at least in simple 1-d systems . this may be valuable in the case when we do not know what is the equation behind the process we observe .
it may also be useful when it is technically difficult to calculate the lyapunov exponent @xcite . in this paper |
6,244 | Suppose that you have an abstract for a scientific paper: we measure the location and evolutionary vectors of 69 _ herschel_-detected broad - line active galactic nuclei ( blagns ) in the @xmath0 plane .
blagns are selected from the cosmos and cdf - s fields , and span the redshift range @xmath1 .
black - hole masses are calculated using archival spectroscopy and single - epoch virial mass estimators , and galaxy total stellar masses are calculated by fitting the spectral energy distribution ( subtracting the blagn component ) .
the mass - growth rates of both the black hole and galaxy are calculated using _ chandra_/_xmm - newton _ x - ray and _ herschel _ far - infrared data , reliable measures of the blagn accretion and galaxy star formation rates , respectively .
we use monte carlo simulations to account for biases in our sample , due to both selection limits and the steep slope of the massive end of the galaxy stellar - mass distribution .
we find our sample is consistent with no evolution in the @xmath0 relation from @xmath2 to @xmath3 .
blagns and their host galaxies which lie off the black hole mass @xmath4 galaxy total stellar mass relation tend to have evolutionary vectors anti - correlated with their mass ratios : that is , galaxies with over - massive ( under - massive ) black holes tend to have a low ( high ) ratio of the specific accretion rate to the specific star formation rate .
we also use the measured growth rates to estimate the preferred agn duty cycle for our galaxies to evolve most consistently onto the local @xmath5 relation . under reasonable assumptions of exponentially declining star formation histories ,
the data suggest a non - evolving ( no more than a factor of a few ) blagn duty cycle among star - forming galaxies of @xmath6 ( @xmath7 range of @xmath8 at @xmath9 and @xmath10 at @xmath11 ) . .
And you have already written the first three sentences of the full article: as the most luminous persistent sources in the universe , active galactic nuclei ( agns ) , which are powered by the mass accretion of super - massive black holes ( smbhs ) , are widely believed to play important roles in the formation and evolution of typical massive galaxies ( for a recent review , see * ? ? ?
* ) . indeed , over the past sixteen years
, many studies have revealed that there are tight correlations between smbhs and the physical properties of host galaxies ( e.g. , * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
* ; * ? ? ? |
6,245 | Suppose that you have an abstract for a scientific paper: we present electronic structure and transport calculations for hydrogen and lithium chains , using density functional theory and scattering theory on the green s function level , to systematically study impurity effects on the transmission coefficient . to this end
we address various impurity configurations .
tight - binding results allow us to interpret our the findings .
we analyze under which circumstances impurities lead to level splitting and/or can be used to switch between metallic and insulating states .
we also address the effects of strongly electronegative impurities . .
And you have already written the first three sentences of the full article: electronic devices have been reduced more and more in size over the last decades .
furthermore it is now possible to place atoms or molecules accurately between macroscopic electrodes , hence experimental studies of the electronic transport for single atoms @xcite , molecules @xcite , and nanowires @xcite have become available .
one - dimensional structures are of particular interest due to their restricted transport channels , making them prototypical model systems ..
Please generate the next two sentences of the article | for example , mono - atomic chains have been realized by molecular beam epitaxy @xcite .
using the tip of a scanning tunneling microscope , it has been possible to place a row of eight atoms on a nial substrate @xcite . from the theoretical point of view , transport through distorted one - dimensional systems has been addressed already in the early 1990ies by bosonization techniques @xcite . |
6,246 | Suppose that you have an abstract for a scientific paper: we present deep cfht / megacam photometry of the ultra - faint milky way satellite galaxies coma berenices ( comber ) and ursa major ii ( umaii ) .
these data extend to @xmath0 , corresponding to three magnitudes below the main sequence turn - offs in these galaxies .
we robustly calculate a total luminosity of @xmath1 for comber and @xmath2 for umaii , in agreement with previous results .
comber shows a fairly regular morphology with no signs of active tidal stripping down to a surface brightness limit of @xmath3 mag arcsec@xmath4 . using a maximum likelihood analysis
, we calculate the half - light radius of comber to be @xmath5pc ( @xmath6 ) and its ellipticity @xmath7 .
in contrast , umaii shows signs of on - going disruption .
we map its morphology down to @xmath8 mag arcsec@xmath4 and found that umaii is larger than previously determined , extending at least @xmath9pc ( @xmath10 on the sky ) and it is also quite elongated with an ellipticity of @xmath11 .
however , our estimate for the half - light radius , @xmath12pc ( @xmath13 ) is similar to previous results .
we discuss the implications of these findings in the context of potential indirect dark matter detections and galaxy formation .
we conclude that while comber appears to be a stable dwarf galaxy , umaii shows signs of on - going tidal interaction . .
And you have already written the first three sentences of the full article: for decades , only about a dozen dwarf galaxies were known to orbit the milky way .
the majority of these systems corresponded to dwarf spheroidal ( dsph ) galaxies , the least luminous , but , by number , the dominant galaxy type in the present - day universe .
however , over the last five years , and thanks to the advent of the sloan digital sky survey ( sdss ; @xcite ) the field of dwarf galaxies in the milky way has been revolutionized ..
Please generate the next two sentences of the article | to date , fourteen new systems have been detected as slight overdensities in star count maps using the sdss data ( @xcite ; @xcite ; @xcite ; @xcite ; @xcite ; @xcite ) .
these recent discoveries have revealed a previously unknown population of `` ultra - faint '' systems which have extreme low luminosities , in some cases as low as @xmath14l@xmath15 @xcite , and in average comparable ( or lower ) to those of galactic globular clusters . |
6,247 | Suppose that you have an abstract for a scientific paper: we investigate crossing path probabilities for two agents that move randomly in a bounded region of the plane or on a sphere ( denoted @xmath0 ) . at each discrete time - step
the agents move , independently , fixed distances @xmath1 and @xmath2 at angles that are uniformly distributed in @xmath3 .
if @xmath0 is large enough and the initial positions of the agents are uniformly distributed in @xmath0 , then the probability of paths crossing at the first time - step is close to @xmath4)$ ] , where @xmath5 $ ] is the area of @xmath0 .
simulations suggest that the long - run rate at which paths cross is also close to @xmath6)$ ] ( despite marked departures from uniformity and independence conditions needed for such a conclusion ) . .
And you have already written the first three sentences of the full article: random walks have been studied in abstract settings such as integer lattices @xmath7 or riemannian manifolds ( @xcite , @xcite , @xcite ) . in applied settings
there are many spatially explicit individual - based models ( ibms ) in which the behavior of the system is determined by the meeting of randomly moving agents .
the transmission of a pathogenic agent , the spread of a rumor , or the sharing of some property when randomly moving particles meet are examples that come to mind in biology , sociology , or physics ( @xcite , @xcite , @xcite , @xcite , @xcite ) . in many of these models the movement of agents.
Please generate the next two sentences of the article | is conceptualized as discrete transitions between square or hexagonal cells ( @xcite ) .
however , such a stylized representation of individual movements may not always be entirely realistic . |
6,248 | Suppose that you have an abstract for a scientific paper: by use of the multi - josephson junction model , we investigate voltage - biased i - v characteristics . differently from the case of the single junction ,
i - v characteristics show a complicated behavior due to inter - layer couplings among superconducting phase differences mediated by the charging effect .
we show that there exist three characteristic regions , which are identified by jumps and cusps in the i - v curve . in the low voltage region ,
the total current is periodic with trigonometric functional increases and rapid drops .
then a kind of chaotic region is followed . above certain voltage ,
the total current behaves with a simple harmonic oscillation and the i - v characteristics form a multi - branch structure as in the current - biased case .
the above behavior is the result of the inter - layer coupling , and may be used to confirm the inter - layer coupling mechanism of the formation of hysteresis branches . .
And you have already written the first three sentences of the full article: i - v characteristics of the high t@xmath0 superconductor bi@xmath1sr@xmath1ca@xmath2c@xmath1o@xmath3 ( bscco ) shows a strong hysteresis , producing multi - branches @xcite .
many experiments have been reported to investigate properties of hysteresis branches @xcite , and it has turned out that there is rich physics in properties of i - v characteristics .
substructures are found in hysteresis branches , and are discussed in relation with phonon effects @xcite ..
Please generate the next two sentences of the article | the d - wave effect is also discussed in the higher voltage region , where the tunneling current becomes important @xcite .
it is well known in a single josephson junction that the application of a constant voltage - bias leads a rather simple phenomenon of the harmonic current - oscillation with the frequency proportional to the applied voltage @xcite . |
6,249 | Suppose that you have an abstract for a scientific paper: three giant flares have been detected so far from soft gamma - ray repeaters , each characterized by an initial short hard spike and a pulsating tail .
the observed pulsating tails are characterized by a duration of @xmath0 , an isotropic energy of @xmath1 , and a pulse period of a few seconds .
the pulsating tail emission likely originates from the residual energy after the intense energy release during the initial spike , which forms a trapped fireball composed of a photon - pair plasma in a closed field line region of the magnetars .
observationally the spectra of pulsating tails can be fitted by the superposition of a thermal component and a power - law component , with the thermal component dominating the emission in the early and late stages of the pulsating tail observations . in this paper , assuming that the trapped fireball is from a closed field line region in the magnetosphere , we calculate the atmosphere structure of the optically - thick trapped fireball and the polarization properties of the trapped fireball . by properly treating the photon propagation in a hot , highly magnetized , electron - positron pair plasma , we tally photons in two modes ( o mode and e mode ) at a certain observational angle through monte carlo simulations .
our results suggest that the polarization degree depends on the viewing angle with respect to the magnetic axis of the magnetar , and can be as high as @xmath2 in the @xmath3 band , and @xmath4 in the @xmath5 band , if the line of sight is perpendicular to the magnetic axis . .
And you have already written the first three sentences of the full article: magnetars are neutron stars with super - strong magnetic fields .
the typical magnetic strength of magnetars is of the order of @xmath6 , which is higher than the critical magnetic field @xmath7 , and is @xmath8 times stronger than that of normal pulsars .
historically , they were discovered in two manifestations , i.e. anomalous x - ray pulsars ( axps ) and soft gamma - ray repeaters ( sgrs ) , even though later observations suggested that there seems no clear distinction between the two sub - categories ..
Please generate the next two sentences of the article | sgrs are discovered in the hard x - ray / soft gamma - ray band characterized by repeating bursts .
eleven sgrs have been confirmed so far @xcite . |
6,250 | Suppose that you have an abstract for a scientific paper: based on quantum electrodynamics , we reexamine the two - photon decay of one - electron atoms .
special attention is paid to the calculation of the ( two - photon ) total decay rates which can be viewed as the imaginary part of the two - loop self - energy .
we argue that our approach can easily be applied to the cases with a virtual state having an intermediate energy between the initial and the final state of the decay process leading , thus , to the resonance peaks in the two - photon energy distribution . in order to illustrate our approach
, we obtain fully relativistic results , resolved into electric and magnetic multipole components , for the two - photon decay rates of the @xmath0 transition in neutral hydrogen as well as in various hydrogen - like ions . .
And you have already written the first three sentences of the full article: since the seminal work of gppert - mayer @xcite , two - photon decay rates of excited states in hydrogen - like atoms and ions have been the subject of intense experimental @xcite and theoretical @xcite studies . for many years , the investigations have dealt not only with the total decay rates but also with the energy and even angular distributions of the two emitted photons . by analyzing these ( two - photon ) properties ,
unique information has been obtained about the structural properties of one - electron systems including subtle relativistic effects as well as about the basic concepts of quantum physics such as , e.g. , the entanglement . even though large experimental and theoretical efforts have been undertaken in the past to understand various aspects of the two - photon decay of hydrogen - like atoms ,
the analysis of this process still raises a number of unresolved problems ..
Please generate the next two sentences of the article | one of these problems , which currently attracts a lot of interest , concerns those two - photon transition from highly excited states to the ground state which pass through an intermediate state with a lower energy than the initial state of the two - photon process @xcite and can alternatively decay to the ground - state via two ( or more ) sequential one - photon emissions .
such a transition leads to resonance peaks in the energy spectrum of the coherently emitted photons from the two - photon decays which are located at the energies corresponding to the ( real ) intermediate states . |
6,251 | Suppose that you have an abstract for a scientific paper: in this article we investigate the role of connectivity in promoting coherent activity in excitatory neural networks . in particular , we would like to understand if the onset of collective oscillations can be related to a minimal average connectivity and how this critical connectivity depends on the number of neurons in the networks .
for these purpouses , we consider an excitatory random network of leaky integrate - and - fire pulse coupled neurons .
the neurons are connected as in a directed erds - renyi graph with average connectivity @xmath0 scaling as a power law with the number of neurons in the network .
the scaling is controlled by a parameter @xmath1 , which allows to pass from massively connected to sparse networks and therefore to modify the topology of the system . at a macroscopic level
we observe two distinct dynamical phases : an asynchronous state ( as ) corresponding to a desynchronized dynamics of the neurons and a partial synchronization ( ps ) regime associated with a coherent periodic activity of the network . at low connectivity
the system is in an asynchronous state , while ps emerges above a certain critical average connectivity @xmath2 . for sufficiently large networks , @xmath2 saturates to a constant value suggesting that a minimal average connectivity is sufficient to observe coherent activity in systems of any size irrespectively of the kind of considered network : sparse or massively connected .
however , this value depends on the nature of the synapses : reliable or unreliable .
for unreliable synapses the critical value required to observe the onset of macroscopic behaviors is noticeably smaller than for reliable synaptic transmission . due to the disorder present in the system , for finite number of neurons we have inhomogeneities in the neuronal behaviors , inducing a weak form of chaos , which vanishes in the thermodynamic limit .
in such a limit the disordered systems exhibit regular ( non chaotic ) dynamics and their properties correspond to that of a....
And you have already written the first three sentences of the full article: neural collective oscillations have been observed in very many context in brain circuits , ranging from ubiquitous @xmath1 oscillations to @xmath3 rhythm in the hippocampus .
the origin of these oscillations is commonly associated with the balance between excitation and inhibition in the network , while purely excitatory circuits are believed to lead to `` unstructured population bursts '' @xcite .
however , recent ` ex vivo' measurements performed on the rodent neocortex @xcite and hippocampus @xcite in the early stage of brain maturation reveal coherent activity patterns , such as _ giant depolarizing potentials_. these collective oscillations emerge despite the fact that the gaba transmitter has essentially an excitatory effect on immature neurons @xcite ..
Please generate the next two sentences of the article | therefore , also in purely excitatory networks one can expect non trivial dynamics at a macroscopic level .
numerical and theoretical studies of collective motions in networks of simple spiking neurons have been mainly devoted to balanced excitatory - inhibitory configurations , e.g see @xcite and references therein . |
6,252 | Suppose that you have an abstract for a scientific paper: the dirac oscillator coupled to an external two - component field can retain its solvability , if couplings are appropriately chosen .
this provides a new class of integrable systems .
a simplified way of solution is given , by recasting the known solution of the dirac oscillator into matrix form ; there one notices , that a block - diagonal form arises in a hamiltonian formulation .
the blocks are two - dimensional . choosing couplings that do not affect the block structure ,
these blow up the @xmath0 matrices to @xmath1 matrices , thus conserving solvability .
the result can be cast again in covariant form . by way of example
we apply this exact solution to calculate the evolution of entanglement . .
And you have already written the first three sentences of the full article: the dirac oscillator @xcite has attracted considerable attention both due to its simple formulation and its analytical solutions . yet
we may ask , if we can go beyond the single particle problem and conserve some of that elegance and simplicity . a plausible scenario in particle physics
is that of a dirac particle bound by an oscillator and interacting with an external ( free ) non - abelian field of mesons modeled as particles with finite radius @xcite . specifically , if the internal group of the interaction is chosen to be @xmath2 and the non - local potential dependence is linear in the position and momentum operators , the structure which leads to integrability is preserved ..
Please generate the next two sentences of the article | this linearity can also be viewed as an approximation to a more complicated field .
the central subject of this paper will thus be to develop this scenario for one , two and three dimensional dirac oscillators . to achieve this |
6,253 | Suppose that you have an abstract for a scientific paper: through a discussion of some typical unsteady hydrodynamic flows , we argue that the time averaged hydrodynamic functions at each point give a rather sparse filling of the local jet space .
this situation then suggests a set of time dependent probability functions that are shown to give evolution uniquely defined by the navier - stokes equations through a set of `` differential distribution equations . ''
the closure relations are therefore unique and have no ad hoc characteristics .
annealing methods are proposed as a way to arrive at the stable stationary solutions corresponding to time averaged fluid flow with constant driving forces and fixed boundary conditions .
some applications of this method to quantum statistical mechanics and kinetic theory to higher orders are suggested .
the treatment of turbulence and otherwise unsteady flow in hydrodynamics is an old problem with enduring relevance @xcite . given that most large energetic fluid systems have enormous reynolds numbers , turbulence is an essential part of the process of conveying strain , heat and material across them . even as a microscopic physical understanding of fluidity and the liquid state remains elusive
, so fluids have enduring mysteries at large scales . computational power for simulation grows while analytic approaches and closure schemes for them proliferate yet our confidence in the results is often undermined by their ad hoc nature .
anticipating that turbulence would be adequately characterized by a mean flow and some fluctuations about it , reynolds introduced an averaging scheme for the velocity @xmath0 .
this gives a mean motion driven by the mean pressure and mean viscosity but with a density dependent `` stress '' term @xcite .
how to treat this stress term is the main complication in the analysis of hydrodynamics of turbulent flow .
analogously , in kinetic theory , the collision term in the evolution of the distribution function @xmath1 is handled by the assumption of `` molecular chaos . '' in the....
And you have already written the first three sentences of the full article: laminar flow is the case of a flow that persists in a stationary fashion at each point .
such flow is either static or found in the case of uniformly driven boundary conditions or external forces .
the well - definedness of the term is a bit in doubt in the case of time varying boundaries ..
Please generate the next two sentences of the article | if the boundaries move in a periodic fashion and the flow does as well , it might be considered to be laminar even though the flowlines are not time independent .
an unambiguous notion of unsteady flow might be given by the notion of bifurcation as we see in the case of the van karman vortex street . |
6,254 | Suppose that you have an abstract for a scientific paper: metallic diffusion - limited aggregate ( dla ) films are well - known to exhibit near - perfect broadband optical absorption .
we demonstrate that such films also manifest a substantial and relatively material - independent photoacoustic response , as a consequence of their random nanostructure .
we theoretically and experimentally analyze photoacoustic phenomena in dla films , and show that they can be used to create broadband air - coupled acoustic sources .
these sources are inexpensive and simple to fabricate , and work into the ultrasonic regime .
we illustrate the device possibilities by building and testing an optically - addressed acoustic phased array capable of producing virtually arbitrary acoustic intensity patterns in air . .
And you have already written the first three sentences of the full article: stochastically nanostructured materials exhibit optical , electronic , and thermal properties which can differ drastically from those of ordered nanostructures and of homogeneous samples of the same material . in nanostructured aggregates ,
a combination of strong broadband optical absorption and fast local thermal response gives rise to a strong photoacoustic effect , in which amplitude - modulated light is transduced to sound at the frequency of amplitude modulation . in this work
we theoretically and experimentally investigate the photoacoustic response of nanostructured aggregates in air , and demonstrate that such materials enable the construction of acoustic sources including an optically - addressed photoacoustic phased array ..
Please generate the next two sentences of the article | the flexibility of such acoustic sources could enable low - cost generation of arbitrary broadband acoustic and ultrasonic waveforms , with potential applications ranging from subdiffraction air - coupled acoustic sources to materials characterization .
the study of photoacoustic phenomena in bulk materials has an illustrious history @xcite , and the effect has proven useful as a characterization tool in a variety of contexts @xcite . |
6,255 | Suppose that you have an abstract for a scientific paper: we obtain new five - dimensional supersymmetric rotating multi - kaluza - klein black hole solutions with the gdel parameter in the einstein - maxwell system with a chern - simons term .
these solutions have no closed timelike curve outside the black hole horizons . at the infinity ,
the space - time is effectively four - dimensional .
each horizon admits various lens space topologies @xmath0 in addition to a round @xmath1 .
the space - time can have outer ergoregions disjointed from the black hole horizons , as well as inner ergoregions attached to each horizon .
we discuss the rich structures of ergoregions . .
And you have already written the first three sentences of the full article: in recent years , kaluza - klein black hole solutions have been studied by many authors in the context of string theory .
since kaluza - klein black hole solutions have compactified extra dimensions , the space - time effectively behaves as four - dimensions at the infinity .
the first kaluza - klein black hole solutions with an extra twisted s@xmath2 were found by dobiasch and maison @xcite as vacuum solutions to the five - dimensional einstein equation , and the features of the black hole were investigated by gibbons and wiltshire @xcite ..
Please generate the next two sentences of the article | the static charged kaluza - klein black holes were also found in the five - dimensional einstein - maxwell theory @xcite and were generalized to the rotating case as the solutions in the five - dimensional einstein - maxwell theory with a chern - simons term @xcite .
supersymmetric rotating kaluza - klein black hole solutions were found by gaiotto _ |
6,256 | Suppose that you have an abstract for a scientific paper: a bouncing droplet on a vibrated bath can couple to the waves it generates , so that it becomes a propagative walker .
its propulsion at constant velocity means that a balance exists between the permanent input of energy provided by the vibration and the dissipation .
here we seek a simple theoretical description of the resulting non - hamiltonian dynamics with a walker immersed in a harmonic potential well .
we demonstrate that the interaction with the recently emitted waves can be modeled by a rayleigh - type friction .
the rayleigh oscillator has well defined attractors .
the convergence toward them and their stability is investigated through an energetic approach and a linear stability analysis .
these theoretical results provide a description of the dynamics in excellent agreement with the experimental data .
it is thus a basic framework for further investigations of wave - particle interactions when memory effects are included . .
And you have already written the first three sentences of the full article: from the simple pendulum to more complex oscillators , the unavoidable coupling with the environment generates dissipation .
even if the loss of energy is balanced by a permanent input , the hamiltonian structure is lost .
the description of open systems , i.e. when the coupling with the environment can not be neglected , has been explored in the framework of self - sustained oscillators ..
Please generate the next two sentences of the article | a theoretical approach was first developed by van der pol @xcite to describe the spontaneous regular heartbeats @xcite .
this oscillator is characterized by an amplitude - dependent friction term : the oscillation is amplified for a small amplitude and damped for a larger one . |
6,257 | Suppose that you have an abstract for a scientific paper: i review the observed temporal x - ray properties of galactic black hole candidates and the status of theoretical modeling of these properties . like spectral x - ray properties , which has so
far attracted most of the attention , the temporal properties , such as power spectral density , hard x - ray time lags , and coherence functions , contain information on some of the same physical properties of inverse comptonization processes , which are generally believed to be responsible for producing hard x - ray emission in black hole candidates .
in addition , the temporal properties add new information about the size of the comptonizing region and perhaps its density structure . therefore , the spectral and temporal properties taken together may help break the degeneracy , intrinsic to most spectral studies , in determining the temperature and optical depth of hot electrons .
moreover , significant insights might be gained into the dynamics of mass accretion in black hole candidates from the inferred density structure of accreted gas ( from the temporal properties ) . unfortunately , until very recently little has been done to _ quantitatively _ model the observed temporal properties of black hole candidates .
i will discuss the recently proposed models , which have been formulated in the context of thermal comptonization , and compare them to the data .
emphasis will be made on simultaneous studies of the observed spectral and temporal properties , the ultimate approach to studying x - ray production mechanisms in galactic black holes . .
And you have already written the first three sentences of the full article: much has been discussed about the observed spectral x - ray properties of black hole candidates ( bhcs ) and numerous models that have been developed to account for these properties , during this workshop and in the literature . however , the spectral properties are only part of what we can learn from x - ray observations of these objects .
bhcs are known to exhibit x - ray variability on a wide range of time scales from milliseconds to years ( see , e.g. , asm / rxte light curves on http://space.mit.edu/xte/asm_lc.html ) .
the temporal properties contain information on some of the same physical properties of inverse comptonization processes ( hua & titarchuk 1996 ; cui et al ..
Please generate the next two sentences of the article | 1997 ; kazanas et al .
1997 ) , which are believed to be responsible for producing hard x - ray emission from black hole candidates ( thorne & price 1975 ; coe et al . |
6,258 | Suppose that you have an abstract for a scientific paper: the exact solution of the system consisted from two or three q - bits doped in coupled cavities is discussed .
the problem of indistinguishable between the excited radiators and photons is analyzed using the intrinsic symmetry of the system .
it is demonstrated that the solution is drastically simplified when the radiators and photons are considered as a new polariton excitations .
the exact solution of schrodinger equation is obtained for single and two excitations in each cavity taking into consideration the indistinguishable principle .
this approach opens new possibilities in the interpretation of quantum entangled states in comparison with the traditional distinctive situation ( see for example @xcite ) due to the decreasing of the number of degrees of freedoms in the system . considering that the energies of coupling between the radiators and photons is larger than the coupling with external vacuum field
, we have found the master equation for the dumping of collective excitations of the system of coupled radiators through the cavity fields .
the time - dependence of population for new dressed quasi - levels of energy is obtained solving analytically and numerically the master equation . .
And you have already written the first three sentences of the full article: in recent years the cooperative interaction of @xmath0 two level radiators with cavity electromagnetic field ( emf ) was in the attention of many experimental and theoretical researches @xcite .
this it is connected with the big application of two - level system as a q - bit in quantum processing of information . in many cases , distinguished ensembles of q - bits
are used for the realization of quantum registers @xcite . according to the principle of indistinguishable between the radiators @xcite ,.
Please generate the next two sentences of the article | @xmath1 states of @xmath0 two - level atoms can be reduced to @xmath2 states in the processes of coherent excitation . as a particular case ,
the cooperative effect between two undistinguished radiators occurs , due to the fact that two states of the single excitation ( the atom @xmath3 in an excited state and @xmath4 in the ground and respectively atom @xmath3 in the ground state and @xmath4 in the excited state ) are considered as a same collective state . |
6,259 | Suppose that you have an abstract for a scientific paper: we present a census of the disk population for ukidss selected brown dwarfs in the 5 - 10 myr old upper scorpius ob association . for 116 objects originally identified in ukidss ,
the majority of them not studied in previous publications , we obtain photometry from the wise database . the resulting colour - magnitude and
colour - colour plots clearly show two separate populations of objects , interpreted as brown dwarfs with disks ( class ii ) and without disks ( class iii ) .
we identify 27 class ii brown dwarfs , 14 of them not previously known .
this disk fraction ( 27 out of 116 or 23% ) among brown dwarfs was found to be similar to results for k / m stars in upper scorpius , suggesting that the lifetimes of disks are independent of the mass of the central object for low - mass stars and brown dwarfs .
5 out of 27 disks ( 19% ) lack excess at 3.4 and 4.6@xmath0 m and are potential transition disks ( i.e. are in transition from class ii to class iii ) .
the transition disk fraction is comparable to low - mass stars .
we estimate that the timescale for a typical transition from class ii to class iii is less than 0.4myr for brown dwarfs .
these results suggest that the evolution of brown dwarf disks mirrors the behaviour of disks around low - mass stars , with disk lifetimes on the order of 5 - 10myr and a disk clearing timescale significantly shorter than 1myr .
[ firstpage ] techniques : photometric techniques : brown dwarfs open clusters and associations : individual : upper scorpius infrared : stars . .
And you have already written the first three sentences of the full article: brown dwarfs substellar objects with masses below the hydrogen burning limit of 0.08@xmath1 are ideal to test the mass dependence of critical parameters in stellar evolution .
one example for such a parameter is the lifetime of circumstellar disks , which is an important constraint for the core - accretion scenarios for planet formation .
the disk lifetime is affected by a number of physical processes , e.g. disk ionisation by the central object and cosmic rays , accretion , grain growth ( e.g. @xcite ) ..
Please generate the next two sentences of the article | our understanding of the relative importance of these processes and how they change with object mass is still incomplete , i.e. observational guidance is important to advance the theory .
the clear majority of low - mass stars lose their disk within less than 5myr @xcite . |
6,260 | Suppose that you have an abstract for a scientific paper: realistic quark masses and mixing angles are obtained applying the successful @xmath0 family symmetry for leptons , motivated by the quark - lepton assignments of su(5 ) .
the @xmath0 symmetry is suitable to give tri - bimaximal neutrino mixing matrix which is consistent with current experimental data .
we study new scenario for the quark sector with the @xmath0 symmetry .
* quark and lepton mass matrices + with @xmath0 family symmetry * + + .
And you have already written the first three sentences of the full article: the current observed neutrino mixing @xcite suggests around the maximal 2 - 3 mixing angle and zero 1 - 3 mixing angle : @xmath1 , @xmath2 .
in such a symmetric limit where both @xmath3 and @xmath4 vanish , the resulting @xmath5 effective majorana neutrino mass matrix forms in the flavor basis as @xcite ( ccc x & c & c + c & a & b + c & b & a ) .
[ m - z2 ] this matrix has an exact symmetric form under a @xmath6 symmetry , i.e. the 2 - 3 ( @xmath7-@xmath8 ) permutation , and is diagonalized by the unitary matrix : u_z_2 = ( ccc _ 12 & -_12 & 0 + _ 12/ & _ 12/ & -1/ + _ 12/ & _ 12/ & 1/ ) , with remaining the solar mixing angle @xmath9 arbitrary and the entry @xmath10 of ( [ m - z2 ] ) is determined as x = a + b + ..
Please generate the next two sentences of the article | now we well know two special values for @xmath9 which give typical mixing matrices ; one is bimaximal and the other is tri - bimaximal mixing matrices . in a limit of bimaximal mixing @xcite where @xmath11 , resulting mns matrix forms u_bm = ( ccc 1/ & -1/ & 0 + 1/2 & 1/2 & -1/ + 1/2 & 1/2 & 1/ ) , with x = a + b. for the case @xmath12 with so - called tri - bimaximal mixing which is proposed by harrison , perkins and scott , then we have the hps type matrix @xcite : u_hps = ( ccc 2/ & 1/ & 0 + -1/ & 1/ & -1/ + -1/ & 1/ & 1/ ) , where @xmath9 is fixed by as well x = a + b + c is also derived .
note that the tri - bimaximal structure is consistent with current experimental data , where @xmath9 is not maximal . |
6,261 | Suppose that you have an abstract for a scientific paper: despite indications that classical cataclysmic variable ( cv ) stars are rare in globular clusters in general , and in the cluster ngc6624 in particular , we have serendipitously discovered such a star @xmath0 from the cluster center .
a _ hubble space telescope _
spectrum of the @xmath1 object shows strong , broad emission lines typical of numerous field cvs , and the inferred optical and uv luminosity are also similar .
our accidental observation also provides the first high - quality ultraviolet spectrum of a globular cluster cv . that we have detected such an object in an observation that includes just a few percent of the central area of the cluster
may indicate that cluster cvs are more common than previously thought , at least near the core .
-0.6 in 9.6 in 0.210 in accepted for publication in the astronomical journal + to appear in the 1999 december issue , volume 118 + _ received 1999 july 28 ; accepted 1999 august 31 _ .
And you have already written the first three sentences of the full article: a small number of close binary stars are thought to dominate the dynamic evolution of many globular star clusters ( hut et al .
1992 , bailyn 1995 ) , yet classes of such objects which are relatively easily found in the field have proven frustratingly difficult to discover in clusters .
a prime example is cataclysmic variables ( cvs ) , which call attention to themselves via large amplitude light outbursts , and peculiar , ultraviolet - excess colors in quiescence . with quiescent absolute magnitudes @xmath2.
Please generate the next two sentences of the article | , modern ground - based photometric techniques should easily uncover such objects in clusters with typical distances of @xmath3 , even with modest telescopes , unless all such objects are lost to the crowded cores . yet
prior to the launch of _ hubble space telescope _ ( _ hst _ ) , we are aware of only two candidate identifications of cvs in globular clusters , m5 v101 ( margon et al . 1981 ) , whose classification and cluster membership seems secure ( naylor et al . |
6,262 | Suppose that you have an abstract for a scientific paper: we report the results of extended high resolution numerical integrations of the vlasov
poisson equation for the collapse of spherically symmetric wdm halos . for thermal relics with mass @xmath0kev/@xmath1
, we find collapsed halos with cores of size from @xmath2 to @xmath3kpc .
the typical core is hollow , with the mass density decreasing towards the core center by almost three orders of magnitude from its maximum near the core radius @xmath4 .
the core is in equilibrium with the diffused part of the halo but far from virialization .
these properties are rooted in the conservation of the squared angular momentum and in the original excess , proper of wdm initial conditions , of kinetic energy in the core region . in a sample of more than one hundred simulated collapses ,
the values of @xmath4 and of the core density @xmath5 are in the range typical of dwarf spheroids , while the maximal circular velocities @xmath6 are proper of small disk galaxies .
the product @xmath7 takes values between @xmath8pc@xmath9 and @xmath10pc@xmath9 , while the surface density @xmath11 , as determined from a burkert fit , is roughly three times larger . from these data and data obtained at smaller values of @xmath12
, we extrapolate for one particular halo @xmath13pc@xmath9 and @xmath14pc@xmath9 at @xmath15kev/@xmath1 , to be compared with the observed value @xmath16/pc@xmath9 . in view of the many improvements and enhancements available ,
we conclude that wdm is a viable solution for explaining the presence and the size of cores in low mass galaxies . .
And you have already written the first three sentences of the full article: the investigation on how purely self gravitating matter evolves on long time scales has played and still plays a central role in cosmology , in astrophysics and in statistical mechanics . from the statistical point of view , the main obstacle towards the establishment of a general picture is the lack of simple additivity due to the long range interaction .
this prevents a system , even if composed by a macroscopic number of `` particles '' , to reach thermodynamic equilibrium , so that the usual laws of equilibrium thermodynamics do not apply @xcite .
conversely , it is well known that there exist infinitely many stable equilibrium phase space configurations to choose from as @xmath17 @xcite ..
Please generate the next two sentences of the article | still , relaxation of some sort must occur , since self gravitating systems of many different kinds and sizes appear to be in ( quasi ) stationary states @xcite .
likewise , numerical @xmath18body simulations of such systems show that , from a coarse grained point of view , some type of equilibration does occur @xcite . |
6,263 | Suppose that you have an abstract for a scientific paper: our previous study of the faint end ( [email protected] ) of the galaxy luminosity function ( glf ) was based on spectroscopic data in a small region near the coma cluster center . in this previous study adami et al .
( 1998 ) suggested , with moderate statistical significance , that the number of galaxies actually belonging to the cluster was much smaller than expected .
this led us to increase our spectroscopic sample . here , we have improved the statistical significance of the results of the coma glf faint end study ( [email protected] ) by using a sample of 88 redshifts .
this includes both new spectroscopic data and a literature compilation . the relatively small number of faint galaxies belonging to coma that was suggested by adami et al .
( 1998 ) and secker et al .
( 1998 ) has been confirmed with these new observations .
we also confirm that the color - magnitude relation is not well suited for finding the galaxies inside the coma cluster core , close to the center at magnitudes fainter than r@xmath119 .
we show that there is an enhancement in the coma line of sight of field galaxies compared to classical field counts .
this can be explained by the contribution of groups and of a distant @xmath2 cluster along the line of sight .
the result is that the coma glf appears to turn - over or at least to become flat for the faint galaxies .
we suggest that this is due to environmental effects .
galaxies : clusters : individual : coma cluster - galaxies : distances and redshifts - galaxies : luminosity function , mass function - cosmology : observations .
And you have already written the first three sentences of the full article: the galaxy luminosity function ( glf hereafter ) is a powerful cosmological tool ( see e.g. the review by binggeli , sandage @xmath3 tammann 1988 ) . it is a good indicator of the formation history of both galaxies and clusters of galaxies , and is also directly related to the mass distribution function of structures in the universe ( press @xmath3 schechter 1974 ) . excluding environmental effects as a first approximation , hierarchical models predict a mass distribution characterized by an exponential cut - off beyond a characteristic mass m@xmath4 and a power - law for low mass structures .
although a detailed analysis presented by binggeli et al . ( 1988 ) shows that individual galaxy types actually have a gaussian distribution , except for the dwarf ellipticals ( probably the dominant type among the faint coma galaxies ) , the glf is now commonly described with a schechter function ( see e.g. lumsden et al .
1997 or rauzy et al ..
Please generate the next two sentences of the article | 1998 for recent statistical applications ) .
it is possible to find a simple linear relation between the shape of the power spectrum ( fourier transform of the mass function ) and the shape of the glf ( see lobo et al . |
6,264 | Suppose that you have an abstract for a scientific paper: we report on the spin properties of individual mn atoms in ii - vi semiconductor strain free quantum dots .
strain free mn - doped cdte quantum dots are formed by width fluctuations in thin quantum wells lattice matched on a cdte substrate .
these quantum dots permit to optically probe and address any spin state of a mn atom in a controlled strain environment .
the absence of strain induced magnetic anisotropy prevents an optical pumping of the mn spin at zero magnetic field .
thus , a large photoluminescence is obtained under resonant optical excitation of the exciton - mn complex .
an efficient optical pumping of the coupled electronic and nuclear spins of the mn is restored under a weak magnetic field .
the observed reduction of the resonant photoluminescence intensity under magnetic field is well described by a model including the hyperfine coupling and a residual crystal field splitting of the mn atom .
finally , we show that the second order correlation function of the resonant photoluminescence presents a large photon bunching at short delay which is a probe of the dynamics of coupled electronic and nuclear spins of the mn atom . .
And you have already written the first three sentences of the full article: the ability to control individual spins in semiconductors nanostructures is an important issue for spintronics and quantum information processing .
the control of single spins in solids is a key but challenging step for any spin - based solid - state quantum - computing device @xcite .
thanks to their expected long coherence time , localized spins on magnetic atoms in a semiconductor host could be an interesting media to store quantum information in the solid state ..
Please generate the next two sentences of the article | optical probing and control of the spin of individual or pairs of mn atoms ( s=5/2 ) have been obtained in self - assembled ii - vi @xcite and iii - v @xcite semiconductor quantum dots ( qds ) .
recent studies of the spin dynamics of mn atoms in self - assembled cdte / znte qds have shown that a strain induced magnetic anisotropy ( _ i.e. _ crystal field splitting ) , changing from dot to dot , blocks the electronic mn spin along the qd growth direction @xcite : the precession of the mn spin in the hyperfine field of its nuclei ( i=5/2 ) or in a weak transverse magnetic field is quenched . |
6,265 | Suppose that you have an abstract for a scientific paper: in this paper , we present charged dilatonic black holes in gravity s rainbow .
we study geometric and thermodynamic properties of black hole solutions .
we also investigate the effects of rainbow functions on different thermodynamic quantities for these charged black holes in dilatonic gravity s rainbow .
then , we demonstrate that first law of thermodynamics is valid for these solutions . after that
, we investigate thermal stability of the solutions using canonical ensemble and analyze the effects of different rainbow functions on thermal stability . in addition , we present some arguments regarding the bound and phase transition points in context of geometrical thermodynamics .
we also study the phase transition in extended phase space in which cosmological constant is treated as the thermodynamic pressure .
finally , we use another approach to calculate and demonstrate that obtained critical points in extended phase space are representing a second order phase transition for these black holes . .
And you have already written the first three sentences of the full article: motivated by works on lifshitz scaling in condensed matter physics , it is possible to take different lifshitz scaling for space and time , and the resultant theory is called horava - lifshitz gravity @xcite . in the ir limit
this gravity reduces to general relativity , and so it can be considered as a uv completion of general relativity . motivated by this work on horava - lifshitz gravity , different lifshitz scaling for space and time have been considered for type iia string theory @xcite , type iib string theory @xcite , ads / cft correspondence @xcite , dilatonic black branes @xcite , and dilatonic black holes @xcite . another uv completion theory of general relativity which reduces to general relativity in the ir limit is called gravity s rainbow @xcite .
in fact , it has been demonstrated that gravity s rainbow is related to horava - lifshitz gravity @xcite ..
Please generate the next two sentences of the article | this is because both of these theories are based on the modifying the usual energy - momentum dispersion relation in the uv limit such that it reduces to the usual energy - momentum dispersion relation in the ir limit .
it may be noted that such modification of the usual energy - momentum has also been obtained in discrete spacetime @xcite , spacetime foam @xcite , spin - network in loop quantum gravity ( lqg ) @xcite , ghost condensation @xcite and non - commutative geometry @xcite . |
6,266 | Suppose that you have an abstract for a scientific paper: in this paper , we make a comprehensive determination of the hubble constant @xmath0 by using two parameters the @xmath1 color and the rate of decline @xmath2to simultaneously standardize the luminosities of all nearby cepheid - calibrated type ia supernovae ( sne ia ) and those of a larger , more distant sample of 29 sne ia . each group is treated in as similar a manner as possible in order to avoid systematic effects .
a simultaneous @xmath3 minimization yields a standardized absolute luminosity of the cepheid - calibrated supernovae as well as the hubble constant obtained from the more distant sample .
we find @xmath4 km s@xmath5 mpc@xmath5 and a standardized absolute magnitude of -19.46 . the sensitivity of @xmath0 to a metallicity dependence of the cepheid - determined distances is investigated . the total uncertainty @xmath6 , dominated by uncertainties in the primary cepheid distance indicator , is estimated to be 5 km s@xmath5 mpc@xmath5 . .
And you have already written the first three sentences of the full article: one requirement for measuring the hubble constant using sne ia as standard candles is a sample of well - measured distant supernovae .
they should be distant enough that their measured redshifts are dominated by the hubble flow , but not so distant that the still - uncertain dynamics associated with deceleration due to the mass density of the universe and possible acceleration due to conjectured repulsive forces are important .
a broad range of redshift @xmath7 from 0.01 to 0.2 is suitable , with @xmath7 about 0.05 being optimum . for this purpose.
Please generate the next two sentences of the article | the carefully measured and uniformly analyzed caln - tololo collection of 29 sne ia ( hamuy et al .
1996 ) covering the range @xmath8 is very well - suited . |
6,267 | Suppose that you have an abstract for a scientific paper: breaking reciprocity associated with wave propagation is a fundamental challenge across a wide range of physical systems in electromagnetics , optics , and acoustics .
in contrast to established magneto - optic methods , recent efforts have focused instead on inducing nonreciprocity using time - varying biases such as synchronized spatiotemporal modulation of resonators and waveguides . to date , the elements that couple these time - varying resonator and waveguide modes are always considered to be reciprocal , and the nonreciprocal transfer functions achieved by these systems have been mostly limited to narrow - band resonances . here
we demonstrate that transferring the time - varying bias to the often overlooked coupling between waveguides and resonators can permit the synthesis of arbitrary nonreciprocal transfer functions . using simple microwave circuits
we experimentally demonstrate dynamically reconfigurable nonreciprocal responses , and the possibility of arbitrary function synthesis , through the use of this nonreciprocal coupler .
this unique method of breaking reciprocity is applicable to essentially all wave phenomena , opening the door for the creation of a broad class of nonreciprocal systems .
reciprocity is a fundamental property of wave propagation in linear time - invariant ( lti ) media @xcite that implies invariance of a system when its inputs and outputs are exchanged and arises due to the symmetry of the medium under time - reversal . in classical systems reciprocity is best captured through network theory , where a reciprocal network is defined by a symmetric scattering matrix @xmath0 @xcite .
the off - diagonal elements of this matrix describe the transmission of waves between any two ports of the network .
since the reciprocity property derives from time - reversal symmetric media , nonreciprocal networks can be created by applying a time - varying bias that generates the property @xmath1 , where @xmath2 is the time variable of the bias .
under such a bias the....
And you have already written the first three sentences of the full article: let us consider a system consisting of a waveguide connecting 2 ports as illustrated in fig .
a resonator supporting a mode with frequency @xmath21 is coupled to this waveguide at @xmath19 independent coupling points , such that each coupler is spatially separated on the waveguide by an identical length @xmath20 . for simplicity , we assume that these couplers are all connected to the resonator at anti - nodes of equal phase for the resonant mode at @xmath21 . using the framework of temporal coupled mode theory @xcite , we will first derive an effective coupling coefficient for this system , and we will show later that the effective coupling is sensitive to the direction of wave propagation when spatiotemporal modulation is applied to the individual coupling coefficients .
the use of coupled mode theory generalizes the analysis allowing for implementation with electromagnetic , optical , or acoustic waves without changing the underlying systemic principles ..
Please generate the next two sentences of the article | we can describe the complex - valued excitation amplitude @xmath16 of the resonant standing wave mode ( traveling modes are discussed in the supplementary information section s1 ) through equation ( [ eqin ] ) , @xmath22 where @xmath21 and @xmath23 describe the frequency and decay rate of the resonance , and @xmath24 is the analysis frequency of the waves traveling into the ports .
waves incident on port 1 , described by @xmath25 , are coupled to the resonator with effective coupling @xmath26 , which is the sum of contributions from all @xmath19 couplers @xmath27 here @xmath28 describes the coupling strength of the @xmath29 coupler , numbered such that @xmath30 is nearest to port 1 and @xmath31 is nearest to port 2 . |
6,268 | Suppose that you have an abstract for a scientific paper: we present a parallel algorithm for calculating very large determinants with arbitrary precision on computer clusters .
this algorithm minimises data movements between the nodes and computes not only the determinant but also all minors corresponding to a particular row or column at a little extra cost , and also the determinants and minors of all submatrices in the top left corner at no extra cost .
we implemented the algorithm in arbitrary precision arithmetic , suitable for very ill conditioned matrices , and empirically estimated the loss of precision .
the algorithm was applied to studies of riemann s zeta function .
* keywords * determinant , linear algebra , parallel algorithms , message passing interface , gpu , riemann s zeta function . .
And you have already written the first three sentences of the full article: parallel linear algebra algorithms have been developed for many hardware architectures with the aim of accelerating routine calculations @xcite . in this paper
we report on our experiences with parallel calculation of determinants of large nearly singular matrices with very high accuracy .
the need to solve such a problem came from research on the famous riemann s _.
Please generate the next two sentences of the article | zeta function_. the distribution of zeroes of zeta function has puzzled mathematicians for over a century .
the famous riemann hypothesis @xcite , which was included by d. hilbert at the very end of xix century as part of his 8-th problem , and which is also one of the clay institute seven millennium problems @xcite , is to prove or disprove that all non - real zeroes of @xmath0 lie on the critical line @xmath1 . among other things , riemann s zeta function |
6,269 | Suppose that you have an abstract for a scientific paper: the influence of the wind to the total continuum of ob supergiants is discussed . for wind velocity distributions with @xmath0 ,
the wind can have strong influence to the total continuum emission , even at optical wavelengths .
comparing the continuum emission of clumped and unclumped winds , especially for stars with high @xmath1 values , delivers flux differences of up to 30% with maximum in the near - ir .
continuum observations at these wavelengths are therefore an ideal tool to discriminate between clumped and unclumped winds of ob supergiants . * wind emission of ob supergiants + and the influence of clumping * + _ * m .
kraus@xmath2 , j. kubt@xmath2 & j. krtika@xmath3 * _ + _ @xmath2astronomick stav , akademie vd esk republiky , ondejov , czech republic _
+ _ @xmath3stav teoretick fyziky a astrofyziky pf mu , brno , czech republic _ 2 .
And you have already written the first three sentences of the full article: the spectra of hot stars show often excess emission at ir and radio wavelengths that can be ascribed to free - free and free - bound ( ff - fb ) emission from their wind zones ( see e.g. panagia & felli @xcite ) .
waters & lamers ( @xcite ) have investigated this excess emission for @xmath4 m and winds with a @xmath1-law velocity distribution of varying @xmath1 , pointing already to the sensitivity of the wind emission to the chosen velocity distribution . over the last few years
, two major effects have become obvious that both strongly influence the wind continuum emission : ( i ) the winds of hot stars seem to be clumped , and ( ii ) many ob supergiants have winds with @xmath5 ( see table [ kraus : tab1 ] ) ..
Please generate the next two sentences of the article | we investigate the wind continuum emission of ob supergiants especially at optical wavelengths .
first , the influence of high @xmath1 values is discussed , and later on the effects of clumping are studied . |
6,270 | Suppose that you have an abstract for a scientific paper: is a transient bursting radio source located in the direction of the galactic center .
it was discovered in a 330 mhz vla observation from 2002 september 30october 1 and subsequently rediscovered in a 330 mhz gmrt observation from 2003 september 28 by hyman et al . here
we report a new radio detection of the source in 330 mhz gmrt data taken on 2004 march 20 .
the observed properties of the single burst detected differ significantly from those measured previously , suggesting that was detected in a new physical state .
the 2004 flux density was @xmath00.05 jy , @xmath010@xmath1 weaker than the single 2003 burst and @xmath030@xmath1 weaker than the five bursts detected in 2002 .
we derive a very steep spectral index , @xmath2 , across the bandpass , a new result previously not detectable due to limitations in the analysis of the 2002 and 2003 observations .
also , the burst was detected for only @xmath02 min .
, in contrast to the 10 min .
duration observed in the earlier bursts . due to sparse sampling , only the single burst was detected in 2004 , as in the 2003 epoch , and we can not rule out additional undetected bursts that may have occurred with the same @xmath077 min .
periodicity observed in 2002 or with a different periodicity .
considering our total time on source throughout both our archival and active monitoring campaigns , we estimate the source exhibits detectable bursting activity @xmath07% of the time . .
And you have already written the first three sentences of the full article: is a novel transient radio source @xcite , whose notable properties have included `` bursts '' with approximately 1 jy peak flux density lasting approximately 10 min .
each and occurring at apparently regular 77 min.intervals .
we first identified from archival 330 mhz ( 90 cm ) observations taken with the very large array ( vla ) on 2002 september 30 ..
Please generate the next two sentences of the article | we then detected a single burst from the source with the giant metrewave radio telescope ( gmrt ) in archival observations from 2003 september 28 at the same frequency .
is located about 1.25 south of the galactic center just outside ( in angular distance ) the shell - type supernova remnant @xcite . the environment of the source is discussed further in @xcite . |
6,271 | Suppose that you have an abstract for a scientific paper: human eye movement mechanisms ( saccades ) are very useful for scene analysis , including object representation and pattern recognition . in this letter , a hopfield neural network to emulate saccades
is proposed .
the network uses an energy function that includes location and identification tasks .
computer simulation shows that the network performs those tasks cooperatively .
the result suggests that the network is applicable to shift - invariant pattern recognition . .
And you have already written the first three sentences of the full article: the human eye is distinguished from commercially available electronic cameras by virtue of having much better resolution in the fovea near the optical axis .
the eccentricity of the retina , which produces a large field of view and high acuity at the fovea , causes the human visual system to have quick jerky eye movements - i.e. , saccades .
it was shown that an artificial visual system equipped with saccades could reduce the number of processing units required for pattern recognition @xcite and could greatly simplify the calculations in low - level vision systems @xcite ..
Please generate the next two sentences of the article | the saccades involve two subtasks ; i.e. , a location task and an identification task .
the location task fixates the location of a pattern in a wide field of view using _ a priori knowledge of the pattern class of interest . on the other hand |
6,272 | Suppose that you have an abstract for a scientific paper: quantum magnets represent an ideal playground for the controlled realization of novel quantum phases and of quantum phase transitions .
the hamiltonian of the system can be indeed manipulated by applying a magnetic field or pressure on the sample . when doping the system with non - magnetic impurities , novel inhomogeneous phases emerge from the interplay between geometric randomness and quantum fluctuations .
in this paper we review our recent work on quantum phase transitions and novel quantum phases realized in disordered quantum magnets .
the system inhomogeneity is found to strongly affect phase transitions by changing their universality class , giving the transition a novel , quantum percolative nature .
such transitions connect conventionally ordered phases to unconventional , quantum disordered ones - quantum griffiths phases , magnetic bose glass phases - exhibiting gapless spectra associated with low - energy localized excitations .
heisenberg antiferromagnets , quantum disorder , geometric randomness , percolation , bose glass .
And you have already written the first three sentences of the full article: quantum phase transitions ( qpts ) and related collective quantum phases represent one of the most exciting research topics in condensed matter physics @xcite .
contrary to thermal phase transitions , qpts occur at zero temperature upon tuning a parameter of the system hamiltonian .
the emergence of quantum collective phenomena opens the path towards quantum phases that do not admit any classical counterpart ..
Please generate the next two sentences of the article | quantum magnets provide a large showcase of materials in which qpts have been experimentally demonstrated .
quantum fluctuations , driving the system through a qpt , can be continuously tuned by _ |
6,273 | Suppose that you have an abstract for a scientific paper: filament eruption on 30 april - 1 may 2010 , which shows the reconnection of one filament leg with a region far away from its initial position , is analyzed .
observations from three viewpoints are used for as precise as possible measurements of endpoint coordinates . the northern leg of the erupting prominence loop jumps laterally to the latitude lower than the latitude of the originally southern endpoint .
thus , the endpoints reshuffled their positions in the limb view .
although this behaviour could be interpreted as the asymmetric zipping - like eruption , it does not look very likely .
it seems more likely to be reconnection of the flux - rope field lines in its northern leg with ambient coronal magnetic field lines rooted in a quiet region far from the filament . from calculations of coronal potential magnetic field
, we found that the filament before the eruption was stable for vertical displacements , but was liable to violation of the horizontal equilibrium .
this is unusual initiation of an eruption with combination of initial horizontal and vertical flux - rope displacements showing a new unexpected possibility for the start of an eruptive event .
[ firstpage ] sun : activity sun : filaments , prominences sun : magnetic fields infrared : stars . .
And you have already written the first three sentences of the full article: many solar filaments ( or prominences when they are observed above the solar limb ) end their life with a sudden rapid rise called an eruption .
sometimes a filament rises like an enlarging loop lying in a plane containing filament endpoints anchored in the chromosphere and the centre of the sun @xcite .
a famous example suggestive of such behaviour is the eruption of the giant prominence on 28 june 1945 ( granddaddy ) observed at the high altitude observatory ..
Please generate the next two sentences of the article | some eruptive prominences deviate significantly from this plane and move in a non - radial direction @xcite
. moreover , the loop may be not flat but the apex exhibits writhing motion as it rotates about the direction of ascent @xcite . |
6,274 | Suppose that you have an abstract for a scientific paper: the phobos experiment at the relativistic heavy ion collider ( rhic ) has collected a large dataset of au+au , cu+cu , d+au and p+p collisions in the center of mass energy range spanning from 19 gev / nucleon to 200 gev / nucleon .
the almost full angular coverage of the phobos detector allows the study of particle production over 10 units pseudorapidity .
the unique design of the spectrometer enables reconstruction and identification of charged particles down to very low transverse momenta . in this
paper properties of the strongly interacting quark - gluon plasma ( sqgp ) created in the nucleus - nucleus collisions at the highest energy available in laboratory are discussed .
results from the phobos experiment on jet suppression , very low @xmath0 particles production and elliptic flow are shown . in more details
are presented the most recent studies of the correlations of charged particles with respect to a high-@xmath0 trigger particle , elliptic flow fluctuations and two particle correlations . .
And you have already written the first three sentences of the full article: the fundamental interactions of quarks and gluons , especially these with large momentum transfer , studied in lepton - hadron and hadron - hadron collisions , are successfully described by quantum chromodynamics ( qcd ) .
a challenge for this theory is the description of larger and more complex systems , necessary for understanding the properties of the matter created in the early stage of the big bang .
conditions similar to that in the early stage of the universe are created in the collisions of heavy nuclei in the relativistic heavy ion collider ( rhic ) at brookhaven national laboratory . in this accelerator the beams of heavy ions , up to au , can be accelerated to the momentum 100 gev / c per nucleon and collide with the highest energy available currently in the laboratory ( @xmath1 = 200 gev ) ..
Please generate the next two sentences of the article | the system created in the collision of two au nuclei reaches , after approximate equilibration at @xmath2 2 fm / c , the energy density of at least 3 gev/@xmath3 .
this energy density is about 6 times larger than that of the proton under normal conditions @xcite . |
6,275 | Suppose that you have an abstract for a scientific paper: the density matrix renormalization group method for ladders works much more efficiently with open boundary conditions .
one consequence of these boundary conditions is groundstate charge density oscillations that often appear to be nearly constant in magnitude or to decay only slightly away from the boundaries .
we analyse these using bosonization techniques , relating their detailed form to the correlation exponent and distinguishing boundary induced generalized friedel oscillations from true charge density waves .
we also discuss a different approach to extracting the correlation exponent from the finite size spectrum which uses exclusively open boundary conditions and can therefore take advantage of data for much larger system sizes
. a general discussion of the friedel oscillation wave - vectors is given , and a convenient fourier transform technique is used to determine it .
dmrg results are analysed on hubbard and @xmath0 chains and 2 leg @xmath0 ladders .
we present evidence for the existence of a long - ranged charge density wave state in the @xmath0 ladder at a filling of @xmath1 and near @xmath2 . .
And you have already written the first three sentences of the full article: bosonization analyses@xcite together with finite size numerical work using the dmrg@xcite and other methods@xcite have given a clear understanding of the behavior of the 2-leg hubbard and @xmath0 ladder models .
the hubbard hamiltonian is written : @xmath3 here @xmath4 destroys an electron on rung @xmath5 and leg @xmath6 with spin @xmath7 .
@xmath8 is the electron number operator ..
Please generate the next two sentences of the article | the @xmath0 hamiltonian is : @xmath9 where @xmath10 and the hilbert space now excludes all states with doubly - occupied sites .
we will generally set @xmath11 in what follows . |
6,276 | Suppose that you have an abstract for a scientific paper: for non - zero @xmath0 values , we present an analytical solution of the radial schrdinger equation for the rotating morse potential using the pekeris approximation within the framework of the asymptotic iteration method .
the bound state energy eigenvalues and corresponding wave functions are obtained for a number of diatomic molecules and the results are compared with the findings of the super - symmetry , the hypervirial perturbation , the nikiforov - uvarov , the variational , the shifted 1/n and the modified shifted 1/n expansion methods . .
And you have already written the first three sentences of the full article: the morse potential has raised a great deal of interest over the years and has been one of the most useful models to describe the interaction between two atoms in a diatomic molecule .
it is known that the radial schrdinger equation for this potential can be solved exactly when the orbital angular quantum number @xmath0 is equal to zero @xcite . on the other hand
, it is also known that for @xmath1 , one has to use some approximations to find analytical or semi - analytical solutions ..
Please generate the next two sentences of the article | several schemes have been presented for obtaining approximate solutions @xcite . among these approximations ,
the most widely used and convenient one is the pekeris approximation @xcite , which is based on the expansion of the centrifugal barrier in a series of exponentials depending on the internuclear distance up to the second order . |
6,277 | Suppose that you have an abstract for a scientific paper: we prove that the kauffman bracket skein algebra of a cylinder over a surface with boundary , defined over complex numbers , is isomorphic to the observables of an appropriate lattice gauge field theory . .
And you have already written the first three sentences of the full article: lattice gauge field theory brings the representation theory of an underlying manifold and its quantum invariants into the same setting .
consider the case of a cylinder over a compact , oriented surface with boundary .
a lattice model of the surface determines an algebra of gauge invariant fields ( i.e. observables ) . in the classical case , based on a connected , simply connected lie group @xmath0 , observables are the characters of the fundamental group of the lattice represented in @xmath0 ..
Please generate the next two sentences of the article | wilson loops can be understood as traces of conjugacy classes in the fundamental group of the lattice .
for the theory based on a drinfeld - jimbo deformation of a simple lie algebra @xmath1 , the observables are a deformation quantization of the @xmath0-characters of the surface with respect to the standard poisson structure @xcite . in the case of @xmath2 |
6,278 | Suppose that you have an abstract for a scientific paper: we review some recent work on the synchronization of coupled dynamical systems on a variety of networks . when nodes show synchronized behaviour , two interesting phenomena can be observed .
first , there are some nodes of the floating type that show intermittent behaviour between getting attached to some clusters and evolving independently .
secondly , two different ways of cluster formation can be identified , namely self - organized clusters which have mostly intra - cluster couplings and driven clusters which have mostly inter - cluster couplings . .
And you have already written the first three sentences of the full article: the phenomena of synchronization of several dynamical variables or oscillators is important for many physical and biological systems @xcite .
some important physical systems showing synchronization are arrays of lasers @xcite , microwave oscillators and superconducting josephson junctions @xcite while some important biological systems are synchronous firing of neurons @xcite , networks of pacemaker cells in the heart @xcite , metabolic synchrony in yeast cell suspensions @xcite , congregations of synchronously flashing fireflies @xcite , and cricket that chirp in unison @xcite .
coupled oscillators were first studied by winfree @xcite and kuramoto @xcite ..
Please generate the next two sentences of the article | the kuramoto model describes a large population of coupled limit cycle oscillators with random frequencies .
if the coupling strength exceeds a critical threshold , the system exhibits a phase transition to a synchronous state where several oscillators synchronize and lock to a common frequency @xcite . |
6,279 | Suppose that you have an abstract for a scientific paper: we investigate the exact bright and dark solitary wave solutions of an effective one dimensional ( 1d ) bose - einstein condensate ( bec ) by assuming that the interaction energy is much less than the kinetic energy in the transverse direction .
in particular , following the earlier works in the literature prez - garca et al .
@xcite , serkin et al .
@xcite , grses @xcite and kundu @xcite , we point out that the effective 1d equation resulting from the gross - pitaevskii ( gp ) equation can be transformed into the standard soliton ( bright / dark ) possessing , completely integrable 1d nonlinear schrdinger ( nls ) equation by effecting a change of variables of the coordinates and the wave function .
we consider both confining and expulsive harmonic trap potentials separately and treat the atomic scattering length , gain / loss term and trap frequency as the experimental control parameters by modulating them as a function of time . in the case
when the trap frequency is kept constant , we show the existence of different kinds of soliton solutions , such as the periodic oscillating solitons , collapse and revival of condensate , snake - like solitons , stable solitons , soliton growth and decay and formation of two - soliton like bound state , as the atomic scattering length and gain / loss term are varied .
however when the trap frequency is also modulated , we show the phenomena of collapse and revival of two - soliton like bound state formation of the condensate for double modulated periodic potential and bright and dark solitons for step - wise modulated potentials . , , and bose - einstein condensates ; gross - pitaevskii equation ; nonlinear schrdinger equation ; soliton solutions .
05.45.-a , 03.75.lm , 03.75.nt , 67.85.jk .
And you have already written the first three sentences of the full article: experimental realization of trapped bose - einstein condensates ( bec ) in alkali metal atoms has triggered immense interest in understanding the various properties of ultra cold matter @xcite .
these include four wave mixing , formation of vortices , bright solitons , dark solitons , gap solitons , interference patterns and domain walls in binary becs @xcite .
an interesting dynamical feature in the context of bose - einstein condensation is the formation of matter wave solitons @xcite ..
Please generate the next two sentences of the article | for example , dark solitons @xcite and gap solitons @xcite were experimentally observed in becs with repulsive interactions , whereas bright solitons were demonstrated in systems with attractive interactions @xcite .
the recent experiments at heidelberg and hamburg universities have shown the formation of dark solitons , their oscillations and interaction in single component becs of @xmath0 rb atoms with confining harmonic potential @xcite . |
6,280 | Suppose that you have an abstract for a scientific paper: many networks contain correlations and often conventional analysis is incapable of incorporating this often essential feature . in arxiv:0708.2176
, we introduced the link - space formalism for analysing degree - degree correlations in evolving networks . in this extended version , we provide additional mathematical details and supplementary material .
we explore some of the common oversights when these correlations are not taken into account , highlighting the importance of the formalism .
the formalism is based on a statistical description of the _ fraction of links _
@xmath0 connecting nodes of degrees @xmath1 and @xmath2 . to demonstrate its use
, we apply the framework to some pedagogical network models , namely , random - attachment , barabsi - albert preferential attachment and the classical erds and rnyi random graph . for these three models
the link - space matrix can be solved analytically .
we apply the formalism to a simple one - parameter growing network model whose numerical solution exemplifies the effect of degree - degree correlations for the resulting degree distribution .
we also employ the formalism to derive the degree distributions of two very simple network decay models , more specifically , that of random link deletion and random node deletion .
the formalism allows detailed analysis of the correlations within networks and we also employ it to derive the form of a perfectly non - assortative network for arbitrary degree distribution . .
And you have already written the first three sentences of the full article: networks in particular large networks with many nodes and links are attracting widespread attention .
the classic reviews @xcite with their primary focus on structural properties have been followed up by more recent ones addressing the role of dynamics , such as spreading and synchronisation processes on networks , as well as the role of weights and mesoscopic structures , i.e. cliques ( fully connected subgraphs ) and communities ( groups of densely interconnected nodes ) , within networks @xcite .
although several different measures for characterising networks have been presented , for example in a recent survey @xcite , the simple concept of vertex degree remains unrivalled in its ability to capture fundamental network properties ..
Please generate the next two sentences of the article | when comparing the degrees of connected vertices , however , one often finds that they are correlated , a quality that gives rise to a rich set of phenomena @xcite .
degree correlations constitute a central role in network characterisation and modelling but , in addition to being important in their own right , also have substantial consequences for dynamical processes unfolding on networks . given the increasing current interest in network dynamics , understanding structural correlations remains important and timely . |
6,281 | Suppose that you have an abstract for a scientific paper: we present _ chandra _ , _ xmm - newton _ , and _ swift _ observations of the quiescent neutron star in the transient low - mass x - ray binary maxi j0556332 .
observations of the source made during outburst ( with the _ rossi x - ray timing explorer _ ) reveal tracks in its x - ray color color and hardness
intensity diagrams that closely resemble those of the neutron - star z sources , suggesting that maxi j0556332 had near- or super - eddington luminosities for a large part of its @xmath016 month outburst .
a comparison of these diagrams with those of other z sources suggests a source distance of 46@xmath115 kpc .
fits to the quiescent spectra of maxi j0556332 with a neutron - star atmosphere model ( with or without a power - law component ) result in distance estimates of 45@xmath13 kpc , for a neutron - star radius of 10 km and a mass of 1.4 @xmath2 .
the spectra show the effective surface temperature of the neutron star decreasing monotonically over the first @xmath0500 days of quiescence , except for two observations that were likely affected by enhanced low - level accretion .
the temperatures we obtain for the fits that include a power - law ( @xmath3=184308 ev ) are much higher than those seen for any other neutron star heated by accretion , while the inferred cooling ( @xmath4-folding ) timescale ( @xmath0200 days ) is similar to other sources .
fits without a power - law yield higher temperatures ( @xmath3=190336 ev ) and a shorter @xmath4-folding time ( @xmath0160 days ) .
our results suggest that the heating of the neutron - star crust in maxi j0556332 was considerably more efficient than for other systems , possibly indicating additional or more efficient shallow heat sources in its crust . .
And you have already written the first three sentences of the full article: in the past @xmath015 yr the study of cooling neutron stars in transiently accreting x - ray binaries has emerged as a new approach to understanding the structure of neutron stars .
@xcite discussed how the neutron - star crust in transiently accreting systems could be driven out of thermal equilibrium with the neutron - star core .
some of the heat that is generated by non - equilibrium nuclear reactions deep in the neutron - star crust during an outburst @xcite is radiated away in quiescence and this should result in observable cooling of the neutron - star surface , especially in systems that have undergone long - duration outbursts @xcite . by following the detailed evolution of the surface temperature during quiescence one can then extract information on the properties of the neutron - star crust . the neutron - star transient ks 1731260 provided the first opportunity to test this when it returned to quiescence following an outburst of more than 12.5 yr @xcite . during its first year in quiescence.
Please generate the next two sentences of the article | ks 1731260 indeed showed significant cooling @xcite , and this continued during the next decade @xcite .
following ks 1731260 , cooling of neutron stars heated by transient accretion has been studied in a handful of systems : mxb 165929 @xcite , xte j1701462 @xcite , exo 0748676 @xcite , and igr j174802446 @xcite . |
6,282 | Suppose that you have an abstract for a scientific paper: we review the field theory approach to percolation processes . specifically , we focus on the so - called simple and general epidemic processes that display continuous non - equilibrium active to absorbing state phase transitions whose asymptotic features are governed respectively by the directed ( dp ) and dynamic isotropic percolation ( dip ) universality classes .
we discuss the construction of a field theory representation for these markovian stochastic processes based on fundamental phenomenological considerations , as well as from a specific microscopic reaction - diffusion model realization .
subsequently we explain how dynamic renormalization group ( rg ) methods can be applied to obtain the universal properties near the critical point in an expansion about the upper critical dimensions @xmath0 ( dp ) and @xmath1 ( dip ) .
we provide a detailed overview of results for critical exponents , scaling functions , crossover phenomena , finite - size scaling , and also briefly comment on the influence of long - range spreading , the presence of a boundary , multispecies generalizations , coupling of the order parameter to other conserved modes , and quenched disorder .
+ percolation , epidemic processes , directed percolation , dynamic isotropic percolation , active to absorbing phase transitions , renormalization group theory , dynamic critical phenomena , crossover + 64.60.ak , 05.40.-a , 64.60.ht , 82.20.-w .
And you have already written the first three sentences of the full article: the investigation of the formation and the stationary properties of random structures has been an exciting topic in statistical physics for many years .
since it provides an intuitively appealing and transparent model of the irregular geometry emerging in disordered systems , _ percolation _ has provided a leading paradigm for random structures .
_ bond percolation _ constitutes perhaps the simplest percolation problem ..
Please generate the next two sentences of the article | two fundamental variants of bond percolation have been introduced in the past : in the _ isotropic percolation _ ( ip ) problem the bonds connecting the sites of a regular lattice ( in @xmath2 spatial dimensions ) are randomly assigned to be open ( with probability @xmath3 ) or blocked ( with probability @xmath4 ) , and an agent may traverse an open bond in either direction .
in contrast , in the _ directed percolation _ |
6,283 | Suppose that you have an abstract for a scientific paper: we study electron transport in quasi - one - dimensional metallic wires .
our aim is to compare an impurity - free wire with rough edges with a smooth wire with impurity disorder .
we calculate the electron transmission through the wires by the scattering - matrix method , and we find the landauer conductance for a large ensemble of disordered wires .
we first study the impurity - free wire whose edges have roughness with a correlation length comparable with the fermi wave length . simulating wires with the number of the conducting channels ( @xmath0 ) as large as @xmath1 - @xmath2
, we observe the roughness - mediated effects which are not observable for small @xmath0 ( @xmath3 - @xmath4 ) used in previous works .
first , we observe the crossover from the quasi - ballistic transport to the diffusive one , where the ratio of the quasi - ballistic resistivity to the diffusive resistivity is @xmath5 independently on the parameters of roughness .
second , we find that transport in the diffusive regime is carried by a small effective number of open channels , equal to @xmath6 .
this number is universal - independent on @xmath0 and on the parameters of roughness .
third , we see that the inverse mean conductance rises linearly with the wire length ( a sign of the diffusive regime ) up to the length twice larger than the electron localization length .
we develop a theory based on the weak - scattering limit and semiclassical boltzmann equation , and we explain the first and second observations analytically . for impurity disorder
we find a standard diffusive behavior . finally , we derive from the boltzmann equation the semiclassical electron mean - free path and we compare it with the quantum mean - free path obtained from the landauer conductance .
they coincide for the impurity disorder , however , for the edge roughness they strongly differ , i.e. , the diffusive transport in the wire with rough edges is not semiclassical .
it becomes semiclassical only for roughness with large....
And you have already written the first three sentences of the full article: a wire made of the normal metal is called mesoscopic if the wire length ( @xmath7 ) is smaller than the electron coherence length @xcite .
it is called quasi - one - dimensional ( q1d ) , if @xmath7 is much larger than the width ( @xmath8 ) and thickness ( @xmath9 ) of the wire @xcite .
fabrication of the q1d wires from such metals like au , ag , cu , etc . , usually involves techniques like the electron beam lithography , lift - off , and metal evaporation ..
Please generate the next two sentences of the article | these techniques always provide wires with disorder due to the grain boundaries , impurity atoms and rough wire edges @xcite .
disorder scatters the conduction electrons and limits the electron mean free path ( @xmath10 ) in the wires to @xmath11 nm @xcite . of fundamental interest |
6,284 | Suppose that you have an abstract for a scientific paper: we conducted high dispersion spectroscopic observations of 50 superflare stars with subaru / hds .
these 50 stars were selected from the solar - type superflare stars that we had discovered from the kepler data .
more than half ( 34 stars ) of these 50 target superflare stars show no evidence of binarity , and we estimated stellar parameters of these 34 stars in our previous study ( @xcite , hereafter called paper i ) . according to our previous studies using kepler data , superflare stars show quasi - periodic brightness variations whose amplitude ( 0.1 - 10% ) is much larger than that of the solar brightness variations ( 0.01 - 0.1% ) caused by the existence of sunspots on the rotating solar surface . in this study , we investigated whether these quasi - periodic brightness variations of superflare stars are explained by the rotation of a star with fairly large starspots , by using stellar parameters derived in paper i. first , we confirmed that the value of the projected rotational velocity @xmath0 is consistent with the rotational velocity estimated from the period of the brightness variation .
next , we measured the intensity of ca ii infrared triplet lines and h@xmath1 line , good indicators of the stellar chromospheric activity , and compared them with other stellar properties .
the intensity of ca ii infrared triplet lines indicates that the mean magnetic field strength ( @xmath2 ) of the target superflare stars can be higher than that of the sun .
a correlation between the amplitude of the brightness variation and the intensity of ca ii triplet line was found .
all the targets expected to have large starspots because of their large amplitude of the brightness variation show high chromospheric activities compared to the sun .
these results support that the brightness variation of superflare stars is due to the rotation with large starspots . .
And you have already written the first three sentences of the full article: flares are the energetic explosions in the stellar atmosphere and are thought to occur by intense releases of magnetic energy stored around starspots , like solar flares ( e.g. , @xcite ) .
the total energy released in the largest solar flares is estimated to be of the order of @xmath3 erg ( e.g. , @xcite ; @xcite ) .
superflare " events have been recently found by using the kepler data ( @xcite ; @xcite ) ..
Please generate the next two sentences of the article | superflares are gigantic flare events that are 10-@xmath4 times more energetic ( @xmath5 erg ; @xcite ) than the largest solar flares on the sun ( @xmath6erg ) .
we have analyzed the data from kepler space telescope @xcite , and discovered 365 superflare events on 148 solar - type ( g - type main - sequence ) stars from the data of 83,000 solar - type stars observed for the first 120 days of the kepler mission @xcite . |
6,285 | Suppose that you have an abstract for a scientific paper: we study the fidelity of single qubit quantum gates performed with two - frequency laser fields that have a gaussian or super gaussian spatial mode .
numerical simulations are used to account for imperfections arising from atomic motion in an optical trap , spatially varying stark shifts of the trapping and control beams , and transverse and axial misalignment of the control beams .
numerical results that account for the three dimensional distribution of control light show that a super gaussian mode with intensity @xmath0 provides reduced sensitivity to atomic motion and beam misalignment . choosing a super gaussian with @xmath1 the decay time of finite temperature rabi oscillations
can be increased by a factor of 60 compared to an @xmath2 gaussian beam , while reducing crosstalk to neighboring qubit sites . .
And you have already written the first three sentences of the full article: atomic qubits encoded in hyperfine ground states are one of several approaches being developed for quantum computing experiments@xcite .
single qubit rotations can be performed with microwave radiation or two - frequency laser light driving stimulated raman transitions .
the microwave approach , while simpler in implementation , does not directly yield site resolved operations in a multi - qubit array ..
Please generate the next two sentences of the article | single site selectivity can be achieved with microwaves using a magnetic field gradient@xcite , or tightly focused stark shifting beams@xcite , or with focused two - frequency raman light@xcite . in order to achieve as high a fidelity as possible for qubit rotations
the field strength must be precisely controlled at the location of the atom . |
6,286 | Suppose that you have an abstract for a scientific paper: soft - photon emission rates are calculated within the linear sigma model .
the investigation is aimed at answering the question to which extent the emissivities map out the phase structure of this particular effective model of strongly interacting matter . .
And you have already written the first three sentences of the full article: despite of the increasing success of qcd in describing a large variety of phenomena , both in the perturbative as well as in the non - perturbative regimes , some fundamental questions remain unsolved .
prominent examples are the very nature and detailed properties of the strongly coupled quark gluon plasma which is the conjectured state of qcd matter at temperatures comparable and larger than the qcd energy scale @xmath0 .
furthermore , the nature and properties of the chiral and deconfinement phase transition as well as the position of a conjectured critical point ( cp ) in the qcd phase diagram are among the still challenging issues @xcite ..
Please generate the next two sentences of the article | to answer these questions experimentally , a number of large scale experiments is currently running ( alice , atlas and cms at the lhc , and star and phenix at rhic ) , planned ( mpd at nica ) or under construction ( cbm and hades at fair ) .
on the theory side , lattice qcd yields a smooth crossover from the hadronic phase to the quark - gluon phase for small chemical potential at temperatures of about @xmath1 . at sufficiently large net baryon density |
6,287 | Suppose that you have an abstract for a scientific paper: we report the thickness dependence of dzyaloshinskii - moriya interaction ( dmi ) and spin - orbit torques ( sots ) in pt@xmath0co(t)@xmath0alo@xmath1 , studied by current - induced domain wall ( dw ) motion and second - harmonic experiments . from the dw motion study ,
a monotonous decay of the effective dmi strength with an increasing co thickness is observed , in agreement with a dmi originating at the pt@xmath0co interface .
the study of the ferromagnetic thickness dependence of spin - orbit torques reveals a more complex behavior . the effective sot - field driving the dw motion
is found to initially increase and then saturate with an increasing ferromagnetic thickness , while the effective sot - fields acting on a saturated magnetic state exhibit a non - monotonic behavior with increasing co - thickness .
the observed thickness dependence suggests the spin - hall effect in pt as the main origin of the sots , with the measured sot amplitudes resulting from the interplay between the varying thickness and the transverse spin diffusion length of the co layer . .
And you have already written the first three sentences of the full article: the possibility of manipulating magnetization by spin - currents in a very efficient way is a key requirement for the design of novel spintronic devices @xcite , which promise to change the way digital information is processed and stored . in particular ,
the advantageous scaling of current - induced spin manipulation compared to the oersted field - induced switching allows for lower power operation at small design rules .
the driving mechanism behind current - induced magnetization dynamics pioneered for use in metallic ferromagnets in the last twenty five years has been the spin - transfer torque @xcite ..
Please generate the next two sentences of the article | however , recently a novel and possibly more efficient approach to current - driven magnetization manipulation has been developed .
in particular , very efficient current - induced spin dynamics has been observed in multilayer systems with an ultra - thin ferromagnetic layer sandwiched between two different non magnetic materials @xcite . |
6,288 | Suppose that you have an abstract for a scientific paper: partially obscured agns within a redshift range @xmath0 are used to re - study the role of feedback in the agn - host coevolution issue in terms of their [ oiii]@xmath15007 emission line profile .
the spectra of these objects enable us to determine the agn s accretion properties directly from their broad h@xmath2 emission .
this is essential for getting rid of the `` circular reasoning '' in our previous study of narrow emission - line galaxies , in which the [ oiii ] emission line was used not only as a proxy of agn s bolometric luminosity , but also as a diagnostic of outflow . in addition , the measurement of @xmath3 index is improved by removing an underlying agn s continuum according to the corresponding broad h@xmath2 emission . with these improvements ,
we confirm and reinforce the correlation between @xmath4 and stellar population age .
more important is that this correlation is found to be related to both [ oiii ] line blue asymmetry and bulk blueshift velocity , which suggests a linkage between smbh growth and host star formation through the feedback process .
the current sample of partially obscured agns shows that the composite galaxies have younger host stellar population , higher eddington ratio , less significant [ oiii ] blue wing and smaller bulk [ oiii ] line shift than do the seyfert galaxies .
galaxies : nuclei - galaxies : evolution - quasars : emission line .
And you have already written the first three sentences of the full article: although the nature is still not fully understood at present , active galactic nuclei ( agns ) are widely believed to co - evolve with their host galaxies ( see kormendy & ho 2013 for a recent review ) .
the concept of co - evolution mainly stems from two observational facts : 1 ) the tight correlations between the mass of the central supermassive blackhole ( smbh ) and several properties of the bulge of the host galaxy , including the velocity dispersion , luminosity and mass of the bulge ( e.g. , magorrian et al . 1998 ; gebhardt et al .
2000 ; merritt & ferrarese 2001 ; mclure & dunlop 2002 ; tremaine et al ..
Please generate the next two sentences of the article | 2002 ; haring & rix 2004 ; ferrarese & ford 2005 ; aller & richstone 2007 ; gultekin et al . 2009 ; woo et al .
2010 ) ; 2 ) both agn s accretion and star formation have a peak at similar redshifts of @xmath5 . |
6,289 | Suppose that you have an abstract for a scientific paper: globular clusters offer ideal laboratories to test the predictions of stellar evolution .
when doing so with spectroscopic analyses during the 1990s , however , the parameters we derived for hot horizontal branch stars deviated systematically from theoretical predictions .
the parameters of cooler , a - type horizontal branch stars , on the other hand , were consistent with evolutionary theories . in 1999 , two groups independently suggested that diffusion effects might cause these deviations , which we verified subsequently .
i will discuss these observations and analyses and their consequences for interpreting observations of hot horizontal branch stars . .
And you have already written the first three sentences of the full article: globular clusters are densely packed , gravitationally bound systems of several thousands to about one million stars .
the dimensions of the globular clusters are small compared to their distance from us : half of the light is generally emitted within a radius of less than 10 pc , whereas the closest globular cluster has a distance of 2 kpc and 90% lie more than 5 kpc away .
we can thus safely assume that all stars within a globular cluster lie at the same distance from us . with ages in the order of @xmath0 years globular clusters.
Please generate the next two sentences of the article | are among the oldest objects in our galaxy .
as they formed stars only once in the beginning and the duration of that star formation episode is short compared to the current age of the globular clusters the stars within one globular cluster are essentially coeval . |
6,290 | Suppose that you have an abstract for a scientific paper: we study the distribution of the zeroes of the l - functions of curves in the artin - schreier family .
we consider the number of zeroes in short intervals and obtain partial results which agree with a random unitary matrix model . .
And you have already written the first three sentences of the full article: let @xmath0 be a prime number , @xmath1 its power .
let @xmath2 be a natural number prime to @xmath0 .
we consider the family of curves over @xmath3 defined by an equation of the form [ as]y^p - y = f(x)=a_dx^d+ ... +a_1xwith @xmath4 and @xmath5 for all @xmath6 divisible by @xmath0 ( every curve defined by an equation of the form @xmath7 with @xmath8 $ ] of degree @xmath2 is a twist of a curve of the form satisfying this condition , see section [ geom ] ) ..
Please generate the next two sentences of the article | we call such curves artin - schreier curves , or a - s curves for short , and the corresponding family the a - s family ( with parameter @xmath2 ) .
denote by @xmath9 the set of nontrivial additive characters of @xmath10 . |
6,291 | Suppose that you have an abstract for a scientific paper: in this article we discuss and compare different ways to engineer an interface between ultracold atoms and micro- and nanomechanical oscillators .
we start by analyzing a direct mechanical coupling of a single atom or ion to a mechanical oscillator and show that the very different masses of the two systems place a limit on the achievable coupling constant in this scheme .
we then discuss several promising strategies for enhancing the coupling : collective enhancement by using a large number of atoms in an optical lattice in free space , coupling schemes based on high - finesse optical cavities , and coupling to atomic internal states . throughout the manuscript
we discuss both theoretical proposals and first experimental implementations .
= 1 ultracold atoms , micro- and nanomechanical oscillators , hybrid quantum systems , cavity optomechanics , bose - einstein condensate , ultracold ions , optical lattice , optical cavity .
And you have already written the first three sentences of the full article: recent experiments have demonstrated an impressive level of control over micro- and nanomechanical oscillators .
one key achievement is the engineering of mechanical modes with extremely low dissipation , providing remarkable isolation from the environment @xcite .
a second cornerstone is the detection and manipulation of micro- and nanomechanical motion ..
Please generate the next two sentences of the article | both in solid - state based systems @xcite and cavity optomechanical settings @xcite , techniques have been perfected to monitor position fluctuations with an imprecision down to the standard quantum limit @xcite . moreover ,
sophisticated techniques for cooling and coherent excitation of individual mechanical modes have been developed @xcite , providing access to the quantum ground state @xcite . in the light of these achievements , |
6,292 | Suppose that you have an abstract for a scientific paper: using monte carlo simulations we examine the diffusive properties of the greedy algorithm in the @xmath0-dimensional traveling salesman problem .
our results show that for @xmath1 and 4 the average squared distance from the origin @xmath2 is proportional to the number of steps @xmath3 . in the @xmath4 case
such a scaling is modified with some logarithmic corrections , which might suggest that @xmath4 is the critical dimension of the problem .
the distribution of lengths also shows marked differences between @xmath4 and @xmath5 versions .
a simple strategy adopted by the salesman might resemble strategies chosen by some foraging and hunting animals , for which anomalous diffusive behavior has recently been reported and interpreted in terms of lvy flights .
our results suggest that broad and lvy - like distributions in such systems might appear due to dimension - dependent properties of a search space . .
And you have already written the first three sentences of the full article: although the classical random walk problem is rather well understood by now @xcite , some of its modifications , related , for example , to disordered systems , are less clear @xcite .
departure from the classical random walk manifests often as an anomalous diffusion that appears whenever the typical square displacement of a tracer particle @xmath6 does not obey the normal diffusion law @xmath7 with @xmath8 .
deviations include numerous examples of subdiffusion ( @xmath9 ) such as , for example , photoconductivity of amorphous materials @xcite , diffusion in convective rolls @xcite , or a random walk on the percolation cluster @xcite . on the other hand.
Please generate the next two sentences of the article | , there is much rarer superdiffusive ( @xmath10 ) behavior , of which the richardson diffusion in turbulent fluids is a classical example @xcite .
some macromolecules or biological systems also exhibit anomalous dynamics with superdiffusive behavior , as reported , e.g. , for micelles @xcite or living cell migrations @xcite . |
6,293 | Suppose that you have an abstract for a scientific paper: this review focuses on nuclear reactions in astrophysics and , more specifically , on reactions with light ions ( nucleons and @xmath0 particles ) proceeding via the strong interaction .
it is intended to present the basic definitions essential for studies in nuclear astrophysics , to point out the differences between nuclear reactions taking place in stars and in a terrestrial laboratory , and to illustrate some of the challenges to be faced in theoretical and experimental studies of those reactions .
the discussion revolves around the relevant quantities for astrophysics , which are the astrophysical reaction rates .
the sensitivity of the reaction rates to the uncertainties in the prediction of various nuclear properties is explored and some guidelines for experimentalists are also provided .
_ caminante , son tus huellas el camino , y nada ms ; + caminante , no hay camino , se hace camino al andar .
+ al andar se hace camino y al volver la vista atrs + se ve la senda que nunca se ha de volver de pisar .
+ caminante , no hay camino sino estelas en la mar . + antonio machado _ .
And you have already written the first three sentences of the full article: natural processes proceed simultaneously on many different scales interacting with each other .
this is especially important in astrophysics , where an astronomical observation or a hypothesized system can only be understood by modeling processes on scales spanning many orders of magnitude .
thus , also nuclear physics and astrophysics are closely entwined ..
Please generate the next two sentences of the article | nuclear reactions power quiescent burning of stars and cause the most powerful explosions known .
they not only release or transform energy but also change the composition of the matter in which they occur and thus are responsible for the range of chemical elements found on our planet and throughout the universe . finally , to understand the properties of matter at extreme density and/or density , the nuclear equation of state has to be known . |
6,294 | Suppose that you have an abstract for a scientific paper: we first review the calculations of low invariant mass dilepton production in relativistic heavy ion collisions , using effective hadronic lagrangians .
we go through some of the theoretical techniques used in this kinematical region and we consider some of the appropriate experimental measurements . moving up to the intermediate invariant mass region , we point out some of the uncertainties that show up in theoretical estimates .
those originate mainly from off - shell effects . finally , as an application of hadronic chiral lagrangians at finite temperature , we compute the mass shifts and mixing of the @xmath0 and @xmath1 mesons due to scattering from thermal pions . .
And you have already written the first three sentences of the full article: the field of heavy ion collisions is a very active one , straddling high energy and nuclear physics . at the upper energy limit of this flourishing area of research
, the goal is to eventually produce and study a new state of matter in the laboratory : the quark - gluon plasma ( qgp ) .
that strongly interacting matter in conditions of extreme energy densities undergoes a phase transition is in fact a prediction of qcd @xcite . to confirm whether the phase transition indeed occurs in relativistic heavy ion collisions and.
Please generate the next two sentences of the article | that the qgp is formed , one needs a clear signal as a signature for the qgp .
many approaches have been suggested to elucidate the existence of this elusive state of matter , but unfortunately , no single measurement can be singled - out as a `` smoking gun '' candidate . |
6,295 | Suppose that you have an abstract for a scientific paper: a unique parameterization of secondary ( thermal ) dilepton and photon yields in heavy - ion experiments at cern - sps is proposed . adding those thermal yields to background contributions the spectral shapes of the ceres / na45 , na38 , na50 , helios/3 and wa98 data from experiments with lead and sulfur beams can be well described . .
And you have already written the first three sentences of the full article: electromagnetic radiation represents penetrating probes mapping out the full space - time history of strongly interacting matter in the course of heavy - ion collisions .
particularly interesting is the stage of maximum temperature , where a quark - gluon plasma might be formed .
various properties of the quark - gluon plasma are calculable from first principles exploiting numerical lattice qcd techniques ..
Please generate the next two sentences of the article | the results , such as thermodynamical properties , can be interpreted within quasi - particle models @xcite .
other quantities , such as the electromagnetic emission rates , are accessible within perturbation theory @xcite . |
6,296 | Suppose that you have an abstract for a scientific paper: in the study of open quantum systems , the polaron transformation has recently attracted a renewed interest as it offers the possibility to explore the strong system - bath coupling regime . despite this interest , a clear and unambiguous analysis of the regimes of validity of
the polaron transformation is still lacking . here
we provide such a benchmark , comparing second order perturbation theory results in the original untransformed frame , the polaron frame and the variational extension with numerically exact path integral calculations of the equilibrium reduced density matrix .
equilibrium quantities allow a direct comparison of the three methods without invoking any further approximations as is usually required in deriving master equations .
it is found that the second order results in the original frame are accurate for weak system - bath coupling , the full polaron results are accurate in the opposite regime of strong coupling , and the variational method is capable of interpolating between these two extremes . as the bath becomes more non - markovian ( slow bath ) , all three approaches become less accurate . .
And you have already written the first three sentences of the full article: in many open quantum systems , the coupling between the system and the bath can be considered as a small parameter . in this case
the application of second order perturbation leads to a master equation of redfield or lindblad type @xcite .
their numerical implementation is straightforward and not computationally expensive ..
Please generate the next two sentences of the article | however , for many physical systems of current interest it has been shown that the weak coupling approximation is not justified .
one example is the energy transfer process in photosynthetic complexes where the magnitude of the system - bath coupling is comparable to the electronic couplings @xcite . |
6,297 | Suppose that you have an abstract for a scientific paper: we consider a photon beam incident on a stack of polarizers as an example of a von neumann projective measurement , theoretically leading to the quantum zeno effect .
the maxwell theory ( which is equivalent to the single photon schrdinger equation ) describes measured polarization phenomena , but without recourse to the notion of a projective measurement . .
And you have already written the first three sentences of the full article: the notion of a projective quantum measurement was introduced by von neumann@xcite in his treatise on the mathematical foundations of quantum mechanics .
the idea is the following : ( i ) every quantum measurement yielding the data `` yes '' or `` no '' to an experimental question is described by the projection operators @xmath0 ( for `` yes '' ) or @xmath1 ( for `` no '' ) , @xmath2 ( ii ) if the initial state of a quantum object _ before _
a measurement is @xmath3 , and if the measurement yields the experimental answer `` yes '' to a question @xmath4 , then the state of the quantum object _.
Please generate the next two sentences of the article | after _ the measurement @xmath5 is constructed according to the _ collapse _ of the quantum state rule @xmath6 eq.(2 ) is part of a calculation scheme which is _ not _ a unitary development of the quantum state _ during a measurement_. the unitary behavior ( implicit in the schrdinger equation for a quantum object ) was thought by von neumann to hold only _ between measurements_@xcite . to see how this works ,
consider a beam of photons which has passed through an `` upwards '' polarizer as in figs.1(a ) and ( b ) . |
6,298 | Suppose that you have an abstract for a scientific paper: we solve the problem of maximizing the probability that @xmath0 does not default before @xmath1 within the class of all random variables @xmath2 with given distribution functions @xmath3 and @xmath4 respectively , and construct a dependence structure attaining the maximum .
after translating the maximization problem to the copula setting we generalize it and prove that for each ( not necessarily monotonic ) transformation @xmath5 \rightarrow [ 0,1]$ ] there exists a completely dependent copula maximizing the mass of the endograph @xmath6 of @xmath7 and derive a simple and easily calculable formula for the maximum .
analogous expressions for the minimal mass are given .
several examples and graphics illustrate the main results and falsify some natural conjectures .
copula , dependence , coupling , endograph , markov kernel + 60e05 , 28a50 , 91g70 [ thm]lemma [ thm]proposition [ thm]corollary [ thm]remark [ thm]example [ thm]definition .
And you have already written the first three sentences of the full article: suppose that @xmath3 and @xmath4 are ( continuous ) distribution functions of two default times .
it is well known from coupling theory ( see @xcite ) that there exists a maximal coupling , i.e. a two - dimensional distribution function @xmath8 with marginals @xmath3 and @xmath4 such that for the case of @xmath9 the probability of a joint default @xmath10 is maximal ( within the class of all two - dimensional distribution functions having @xmath3 and @xmath4 as marginals ) .
translating to the class of copulas ( see @xcite and section [ mksklar ] ) , maximizing the probability of a joint default means calculating @xmath11 for @xmath5 \rightarrow [ 0,1]$ ] being defined by @xmath12 , @xmath13 denoting the quasi - inverse of @xmath3 , @xmath14 the graph of @xmath7 , @xmath15 the family of all two - dimensional copulas and @xmath16 being the doubly stochastic measure corresponding to the copula @xmath17 . as pointed out in @xcite.
Please generate the next two sentences of the article | there is a ( not necessarily unique ) copula @xmath18 with @xmath19 that can even be computed in closed form .
considering @xmath20 and setting @xmath21 , the pair @xmath22 has marginal distribution functions @xmath3 and @xmath4 and maximizes the joint default probability . in the current paper |
6,299 | Suppose that you have an abstract for a scientific paper: the physical mechanism responsible for the short outbursts in a recently recognized class of high mass x - ray binaries , the supergiant fast x - ray transients ( sfxts ) , is still unknown .
recent observations performed with @xmath0 , and of the 2007 outburst from igrj11215@xmath15952 , the only sfxt known to exhibit periodic outbursts , suggest a new explanation for the outburst mechanism in this class of transients ; the outbursts could be linked to the possible presence of a second wind component in the supergiant companion , in the form of an equatorial wind .
the applicability of the model to the short outburst durations of all other supergiant fast x - ray transients , where a clear periodicity in the outbursts has not been found yet , is discussed .
the scenario we are proposing also includes the persistently accreting supergiant high mass x ray binaries . .
And you have already written the first three sentences of the full article: supergiant fast x ray transients ( hereafter sfxts ; smith et al .
2006a ) are a new class of hard x ray sources mostly discovered by the @xmath2 satellite ( negueruela et al .
2005a , sguera et al . 2005 ) ..
Please generate the next two sentences of the article | they are transient sources which seem to emit x
rays only during `` short '' outbursts ( few hours , as observed with @xmath2 or @xmath3 ) and their optical counterparts are blue supergiant stars . |
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