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1106.4891
|
the chemical fokker - planck equation and the corresponding chemical langevin equation are commonly used approximations of the chemical master equation . these equations are derived from an uncontrolled , second - order truncation of the kramers - moyal expansion of the chemical master equation and hence their accuracy remains to be clarified . we use the system - size expansion to show that chemical fokker - planck estimates of the mean concentrations and of the variance of the concentration fluctuations about the mean are accurate to order @xmath0 for reaction systems which do not obey detailed balance and at least accurate to order @xmath1 for systems obeying detailed balance , where @xmath2 is the characteristic size of the system . hence the chemical fokker - planck equation turns out to be more accurate than the linear - noise approximation of the chemical master equation ( the linear fokker - planck equation ) which leads to mean concentration estimates accurate to order @xmath3 and variance estimates accurate to order @xmath0 . this higher accuracy is particularly conspicuous for chemical systems realized in small volumes such as biochemical reactions inside cells . a formula is also obtained for the approximate size of the relative errors in the concentration and variance predictions of the chemical fokker - planck equation , where the relative error is defined as the difference between the predictions of the chemical fokker - planck equation and the master equation divided by the prediction of the master equation . for dimerization and enzyme - catalyzed reactions , the errors are typically less than few percent even when the steady - state is characterized by merely few tens of molecules .
| 281
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1501.02266
|
inspired by recent experiments where electron transport was measured across graphene nanoribbons ( gnr ) suspended between a metal surface and the tip of a scanning tunneling microscope [ koch _ et al_. , nat . nanotechnol . * 7 * , 713 ( 2012 ) ] , we present detailed first - principles simulations of inelastic electron tunneling spectroscopy ( iets ) of long pristine and defected armchair and zigzag nanoribbons under a range of charge carrier conditions . for the armchair ribbons we find two robust iets signals around 169 and 196 mv corresponding to the d- and g - modes of raman spectroscopy as well as additional fingerprints due to various types of defects in the edge passivation . for the zigzag ribbons we show that the spin state strongly influences the spectrum and thus propose iets as an indirect proof of spin polarization .
| 148
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astro-ph0510207
|
the situation that a scalar field provides the source of the accelerated expansion of the universe while rolling down its potential is common in both the simple models of the primordial inflation and the quintessence - based dark energy models . motivated by this point , we address the possibility of causing the current acceleration via the primordial inflation using a simple model based on hybrid inflation . we trigger the onset of the motion of the quintessence field via the waterfall field , and find that the fate of the universe depends on the true vacuum energy determined by choosing the parameters . we also briefly discuss the variation of the equation of state and the possible implementation of our scenario in supersymmetric theories . kaist - th/2005 - 16 1.5 cm 0.5 cm 1.2 cm
| 137
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0812.1800
|
it is now well accepted that the galaxies are distributed in filaments , sheets and clusters all of which form an interconnected network known as the cosmic web . it is a big challenge to quantify the shapes of the interconnected structural elements that form this network . tools like the minkowski functionals which use global properties , though well suited for an isolated object like a single sheet or filament , are not suited for an interconnected network of such objects . we consider the local dimension @xmath0 , defined through @xmath1 , where @xmath2 is the galaxy number count within a sphere of comoving radius @xmath3 centered on a particular galaxy , as a tool to locally quantify the shape in the neigbourhood of different galaxies along the cosmic web . we expect @xmath4 and @xmath5 for a galaxy located in a filament , sheet and cluster respectively . using lcdm n - body simulations we find that it is possible to determine @xmath0 through a power law fit to @xmath2 across the length - scales @xmath6 to @xmath7 for @xmath8 of the galaxies . we have visually identified the filaments and sheets corresponding to many of the galaxies with @xmath9 and @xmath6 respectively . in several other situations the structure responsible for the @xmath0 value could not be visually identified , either due to its being tenuous or due to other dominating structures in the vicinity . we also show that the global distribution of the @xmath0 values can be used to visualize and interpret how the different structural elements are woven into the cosmic web . methods : data analysis - galaxies : statistics - large - scale structure of universe
| 285
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1501.01978
|
the m31 globular cluster x - ray binary xb158 ( a.k.a . bo 158 ) exhibits intensity dips on a 2.78 hr period in some observations , but not others . the short period suggests a low mass ratio , and an asymmetric , precessing disk due to additional tidal torques from the donor star since the disk crosses the 3:1 resonance . previous theoretical 3d smoothed particle hydrodynamical modeling suggested a super - orbital disk precession period 29@xmath01 times the orbital period , i.e. @xmath181@xmath03 hr . we conducted a swift monitoring campaign of 30 observations over @xmath11 month in order to search for evidence of such a super - orbital period . fitting the 0.310 kev swift xrt luminosity lightcurve with a sinusoid yielded a period of 5.65@xmath00.05 days , and a @xmath25@xmath3 improvement in @xmath4 over the best fit constant intensity model . a lomb - scargle periodogram revealed that periods 5.45.8 days were detected at a @xmath23@xmath3 level , with a peak at 5.6 days . we consider this strong evidence for a 5.65 day super - orbital period , @xmath170% longer than the predicted period . the 0.310 kev luminosity varied by a factor @xmath15 , consistent with variations seen in long - term monitoring from chandra . we conclude that other x - ray binaries exhibiting similar long - term behaviour are likely to also be x - ray binaries with low mass ratios and super - orbital periods .
| 246
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1406.3836
|
this paper introduces a projected principal component analysis ( projected - pca ) , which employs principal component analysis to the projected ( smoothed ) data matrix onto a given linear space spanned by covariates . when it applies to high - dimensional factor analysis , the projection removes noise components . we show that the unobserved latent factors can be more accurately estimated than the conventional pca if the projection is genuine , or more precisely , when the factor loading matrices are related to the projected linear space . when the dimensionality is large , the factors can be estimated accurately even when the sample size is finite . we propose a flexible semiparametric factor model , which decomposes the factor loading matrix into the component that can be explained by subject - specific covariates and the orthogonal residual component . the covariates effects on the factor loadings are further modeled by the additive model via sieve approximations . by using the newly proposed projected - pca , the rates of convergence of the smooth factor loading matrices are obtained , which are much faster than those of the conventional factor analysis . the convergence is achieved even when the sample size is finite and is particularly appealing in the high - dimension - low - sample - size situation . this leads us to developing nonparametric tests on whether observed covariates have explaining powers on the loadings and whether they fully explain the loadings . the proposed method is illustrated by both simulated data and the returns of the components of the s&p 500 index . ./style / arxiv - general.cfg ,
| 275
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1510.04684
|
device - to - device ( d2d ) communication has seen as a major technology to overcome the imminent wireless capacity crunch and to enable new application services . in this paper , we propose a social - aware approach for optimizing d2d communication by exploiting two layers : the social network and the physical wireless layers . first we formulate the physical layer d2d network according to users encounter histories . subsequently , we propose an approach , based on the so - called indian buffet process , so as to model the distribution of contents in users online social networks . given the social relations collected by the evolved node b ( enb ) , we jointly optimize the traffic offloading process in d2d communication . in addition , we give the chernoff bound and approximated cumulative distribution function ( cdf ) of the offloaded traffic . in the simulation , we proved the effectiveness of the bound and cdf . the numerical results based on real traces show that the proposed approach offload the traffic of enb s successfully .
| 183
|
0902.4734
|
we study the effect of an optical lattice ( ol ) on the ground - state properties of one - dimensional ultracold bosons with three - body attraction and two - body repulsion , which are described by a cubic - quintic gross - pitaevskii equation with a periodic potential . without the ol and with a vanishing two - body interaction term , soliton solutions of the townes type are possible only at a critical value of the three - body interaction strength , at which an infinite degeneracy of the ground - state occurs ; a repulsive two - body interaction makes such localized solutions unstable . we show that the ol opens a stability window around the critical point when the strength of the periodic potential is above a critical threshold . we also consider the effect of an external parabolic trap , studying how the stability of the solitons depends on matching between minima of the periodic potential and the minimum of the parabolic trap .
| 170
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1012.3177
|
the resonance states of one- and two - particle hamiltonians are studied using variational expansions with real basis - set functions . the resonance energies , @xmath0 , and widths , @xmath1 , are calculated using the density of states and an @xmath2 golden rule - like formula . we present a recipe to select adequately some solutions of the variational problem . the set of approximate energies obtained shows a very regular behaviour with the basis - set size , @xmath3 . indeed , these particular variational eigenvalues show a quite simple scaling behaviour and convergence when @xmath4 . following the same prescription to choose particular solutions of the variational problem we obtain a set of approximate widths . using the scaling function that characterizes the behaviour of the approximate energies as a guide , it is possible to find a very good approximation to the actual value of the resonance width .
| 154
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1507.01687
|
this paper describes postfix - gp system , postfix notation based genetic programming ( gp ) , for solving symbolic regression problems . it presents an object - oriented architecture of postfix - gp framework . it assists the user in understanding of the implementation details of various components of postfix - gp . postfix - gp provides graphical user interface which allows user to configure the experiment , to visualize evolved solutions , to analyze gp run , and to perform out - of - sample predictions . the use of postfix - gp is demonstrated by solving the benchmark symbolic regression problem . finally , features of postfix - gp framework are compared with that of other gp systems . + * _ keywords- _ * postfix genetic programming ; postfix - gp framework ; object oriented design ; gp software tool ; symbolic regression
| 147
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0802.3112
|
in the framework of vector measures and the combinatorial approach to stochastic multiple integral introduced by rota and wallstrom [ _ ann . probab . _ * 25 * ( 1997 ) 12571283 ] , we present an it multiple integral and a stratonovich multiple integral with respect to a lvy process with finite moments up to a convenient order . in such a framework , the stratonovich multiple integral is an integral with respect to a product random measure whereas the it multiple integral corresponds to integrate with respect to a random measure that gives zero mass to the diagonal sets . a general hu meyer formula that gives the relationship between both integrals is proved . as particular cases , the classical hu meyer formulas for the brownian motion and for the poisson process are deduced . furthermore , a pathwise interpretation for the multiple integrals with respect to a subordinator is given . , and . .
| 160
|
1111.1801
|
a new cosmological model based on the de sitter gauge theory ( dsgt ) is studied in this paper . by some transformations , we find , in the dust universe , the cosmological equations of dsgt could form an autonomous system . we conduct dynamics analysis to this system , and find 9 critical points , among which there exist one positive attractor and one negative attractor . the positive attractor shows us that our universe will enter a exponential expansion phase in the end , which is similar to the conclusion of @xmath0cdm . we also carry out some numerical calculations , which confirms the conclusion of dynamics analysis . finally , we fit the model parameter and initial values to the union 2 snia dataset , present the confidence contour of parameters and obtain the best - fit values of parameters of dsgt .
| 147
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1410.2536
|
the tammes problem is to find the arrangement of @xmath0 points on a unit sphere which maximizes the minimum distance between any two points . this problem is presently solved for several values of @xmath0 , namely for @xmath1 by l. fejes tth ( 1943 ) ; for @xmath2 by schtte and van der waerden ( 1951 ) ; for @xmath3 by danzer ( 1963 ) and for @xmath4 by robinson ( 1961 ) . recently , we solved the tammes problem for @xmath5 . the optimal configuration of 14 points was conjectured more than 60 years ago . in the paper , we give a solution of this long - standing open problem in geometry . our computer - assisted proof relies on an enumeration of the irreducible contact graphs .
| 132
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1608.03781
|
in this work , we have calculated the mass spectra and decay properties of dimesonic ( meson - antimeson ) bound state in the variational scheme . the intermesonic interaction considered as the hellmann potential and one pion exchange potential . the mass spectra of the @xmath0 , @xmath1 , @xmath2 , @xmath3 , @xmath4 , @xmath5 , @xmath6 , @xmath7 , @xmath8 , @xmath9 , @xmath10,@xmath11 , @xmath12 , @xmath13 , @xmath14 , @xmath15 , @xmath16 , @xmath17 etc .. are calculated . the states x(3872 ) , @xmath18 , @xmath19 and @xmath20 are compared with @xmath0 , @xmath4 , @xmath12 and @xmath15 dimesonic bound states . to probe the molecular structure of the compared states , we have calculated the decay properties sensitive to their long and short distance structure of hadorinc molecule , our results suggested the compared states driven the molecular structure . apart from these the other calculated mass spectra of dimesonoic states are predicted and for such bound states , the experimental search are suggested . pacs numbers : : 12.39.jh , 12.39.pn , 13.25.jx,14.40.rt
| 181
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quant-ph0502058
|
decoherence effects on the traditional @xmath0 vs. @xmath1 photon coherent control of a two - level system are investigated , with 1 vs. 3 used as a specific example . the problem reduces to that of a two - level system interacting with a single mode field , but with an effective rabi frequency that depends upon the fundamental and third harmonic fields . the resultant analytic control solution is explored for a variety of parameters , with emphasis on the dependence of control on the relative phase of the lasers . the generalization to off - resonant cases is noted .
| 102
|
1401.1931
|
barbarians , so named after the prototype of this class ( 234 ) barbara , are a rare class of asteroids exhibiting anomalous polarimetric properties . their very distinctive feature is that they show negative polarization at relatively large phase - angles , where all `` normal '' asteroids show positive polarization . the origin of the barbarian phenomenon is unclear , but it seems to be correlated with the presence of anomalous abundances of spinel , a mineral usually associated with the so - called calcium aluminum - rich inclusions ( cais ) on meteorites . since cais are samples of the oldest solid matter identified in our solar system , barbarians are very interesting targets for investigations . inspired by the fact that some of the few known barbarians are members of , or very close to the dynamical family of watsonia , we have checked whether this family is a major repository of barbarians , in order to obtain some hints about their possible collisional origin . we have measured the linear polarization of a sample of nine asteroids which are members of the watsonia family within the phase - angle range @xmath0 . we found that seven of them exhibit the peculiar barbarian polarization signature , and we conclude that the watsonia family is a repository of barbarian asteroids . the new barbarians identified in our analysis will be important to confirm the possible link between the barbarian phenomenon and the presence of spinel on the surface . [ firstpage ] asteroids : general polarization .
| 260
|
1101.5922
|
dipole models based on various saturation scenarios provide reasonable fits to small - x dis inclusive , diffractive and exclusive data from hera . proton un - integrated gluon distributions extracted from such fits are employed in a @xmath0-factorization framework to calculate inclusive gluon distributions at various energies . the n - particle multiplicity distribution predicted in the glasma flux tube approach shows good agreement with data over a wide range of energies . hadron inclusive transverse momentum distributions expressed in terms of the saturation scale demonstrate universal behavior over a wider kinematic range systematically with increasing center of mass energies . saturation ; lhc p + p collision ; cgc ; deep inelastic scattering
| 115
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1010.4104
|
it is known that the meissner - like effect is seen in a magnetosphere without an electric current in black hole spacetime : no non - monopole component of magnetic flux penetrates the event horizon if the black hole is extreme . in this paper , in order to see how an electric current affects the meissner - like effect , we study a force - free electromagnetic system in a static and spherically symmetric extreme black hole spacetime . by assuming that the rotational angular velocity of the magnetic field is very small , we construct a perturbative solution for the grad - shafranov equation , which is the basic equation to determine a stationary , axisymmetric electromagnetic field with a force - free electric current . our perturbation analysis reveals that , if an electric current exists , higher multipole components may be superposed upon the monopole component on the event horizon , even if the black hole is extreme .
| 163
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1302.3484
|
we develop a theory of parametric resonance in tunable superconducting cavities . the nonlinearity introduced by the squid attached to the cavity , and damping due to connection of the cavity to a transmission line are taken into consideration . we study in detail the nonlinear classical dynamics of the cavity field below and above the parametric threshold for the degenerate parametric resonance , featuring regimes of multistability and parametric radiation . we investigate the phase - sensitive amplification of external signals on resonance , as well as amplification of detuned signals , and relate the amplifier performance to that of linear parametric amplifiers . we also discuss applications of the device for dispersive qubit readout . beyond the classical response of the cavity , we investigate small quantum fluctuations around the amplified classical signals . we evaluate the noise power spectrum both for the internal field in the cavity and the output field . other quantum statistical properties of the noise are addressed such as squeezing spectra , second order coherence , and two - mode entanglement .
| 179
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1307.2979
|
statistical mechanics of two coupled vector fields is studied in the tight - binding model that describes propagation of polarized light in discrete waveguides in the presence of the four - wave mixing . the energy and power conservation laws enable the formulation of the equilibrium properties of the polarization state in terms of the gibbs measure with positive temperature . the transition line @xmath0 is established beyond which the discrete vector solitons are created . also in the limit of the large nonlinearity an analytical expression for the distribution of stokes parameters is obtained which is found to be dependent only on the statistical properties of the initial polarization state and not on the strength of nonlinearity . the evolution of the system to the final equilibrium state is shown to pass through the intermediate stage when the energy exchange between the waveveguides is still negligible . the distribution of the stokes parameters in this regime has a complex multimodal structure strongly dependent on the nonlinear coupling coefficients and the initial conditions .
| 174
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astro-ph0311364
|
we reconstruct the equation of state @xmath0 of dark energy ( de ) using a recently released data set containing 172 type ia supernovae without assuming the prior @xmath1 ( in contrast to previous studies ) . we find that dark energy evolves rapidly and metamorphoses from dust - like behaviour at high @xmath2 ( @xmath3 at @xmath4 ) to a strongly negative equation of state at present ( @xmath5 at @xmath6 ) . dark energy metamorphosis appears to be a robust phenomenon which manifests for a large variety of sne data samples provided one does not invoke the weak energy prior @xmath7 . invoking this prior considerably weakens the rate of growth of @xmath0 . these results demonstrate that dark energy with an evolving equation of state provides a compelling alternative to a cosmological constant if data are analysed in a prior - free manner and the weak energy condition is not imposed by hand . cosmology : theory cosmological parameters statistics
| 163
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1509.07973
|
in this paper we study pairs of polynomials with a given factorization pattern and such that the degree of their difference attains its minimum . we call such pairs of polynomials _ davenport zannier pairs _ , or dz - pairs for short . the paper is devoted to the study of dz - pairs _ with rational coefficients_. in our earlier paper @xcite , in the framework of the _ theory of dessins denfants _ , we established a correspondence between dz - pairs and _ weighted bicolored plane trees_. these are bicolored plane trees whose edges are endowed with positive integral weights . when such a tree is uniquely determined by the set of black and white degrees of its vertices , it is called _ unitree _ , and the corresponding dz - pair is defined over @xmath0 . in @xcite , we classified all unitrees . in this paper , we compute all the corresponding polynomials . in this way , the present paper is a sequel of @xcite . in the final part of the paper we present some additional material concerning the galois theory of dz - pairs and weighted trees .
| 198
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cond-mat9804301
|
the temperature - driven reorientation transition which , up to now , has been studied by use of heisenberg - type models only , is investigated within an itinerant - electron model . we consider the hubbard model for a thin fcc(100 ) film together with the dipole interaction and a layer - dependent anisotropy field . the isotropic part of the model is treated by use of a generalization of the spectral - density approach to the film geometry . the magnetic properties of the film are investigated as a function of temperature and film thickness and are analyzed in detail with help of the spin- and layer - dependent quasiparticle density of states . by calculating the temperature dependence of the second - order anisotropy constants we find that both types of reorientation transitions , from out - of - plane to in - plane ( `` fe - type '' ) and from in - plane to out - of - plane ( `` ni - type '' ) magnetization are possible within our model . in the latter case the inclusion of a positive volume anisotropy is vital . the reorientation transition is mediated by a strong reduction of the surface magnetization with respect to the inner layers as a function of temperature and is found to depend significantly on the total band occupation . -4 mm
| 231
|
astro-ph0408429
|
we study the interplay of clumping at small scales with the collapse and relaxation of perturbations at much larger scales . we present results of our analysis when the large scale perturbation is modelled as a plane wave . we find that in absence of substructure , collapse leads to formation of a pancake with multi - stream regions . dynamical relaxation of plane wave is faster in presence of substructure . scattering of substructures and the resulting enhancement of transverse motions of haloes in the multi - stream region lead to a thinner pancake . in turn , collapse of the plane wave leads to formation of more massive collapsed haloes as compared to the collapse of substructure in absence of the plane wave . the formation of more massive haloes happens without any increase in the total mass in collapsed haloes . a comparison with the burgers equation approach in absence of any substructure suggests that the preferred value of effective viscosity depends primarily on the number of streams in a region . gravitation cosmology : theory dark matter , large scale structure of the universe
| 188
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1503.07688
|
today , prime numbers attained exceptional situation in the area of numbers theory and cryptography . as we know , the trend for accessing to the largest prime numbers due to using mersenne theorem , although resulted in vast development of related numbers , however it has reduced the speed of accessing to prime numbers from one to five years . this paper could attain to theorems that are more extended than mersenne theorem with accelerating the speed of accessing to prime numbers . since that time , the reason for frequently using mersenne theorem was that no one could find an efficient formula for accessing to the largest prime numbers . this paper provided some relations for prime numbers that one could define several formulas for attaining prime numbers in any interval ; therefore , according to flexibility of these relations , it could be found a new branch in the field of accessing to great prime numbers followed by providing an algorithm at the end of this paper for finding the largest prime numbers .
| 177
|
hep-ph9906376
|
a lattice qcd calculation of the @xmath0 decay form factors is presented . we obtain the value of the form factor @xmath1 at the zero - recoil limit @xmath2 with high precision by considering a ratio of correlation functions in which the bulk of the uncertainties cancels . the other form factor @xmath3 is calculated , for small recoil momenta , from a similar ratio . in both cases , the heavy quark mass dependence is observed through direct calculations with several combinations of initial and final heavy quark masses . our results are @xmath4 and @xmath5 . for both the first error is statistical , the second stems from the uncertainty in adjusting the heavy quark masses , and the last from omitted radiative corrections . combining these results , we obtain a precise determination of the physical combination @xmath6 , where the mentioned systematic errors are added in quadrature . the dependence on lattice spacing and the effect of quenching are not yet included , but with our method they should be a fraction of @xmath7 .
| 179
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1307.2649
|
we report the thermodynamic properties of bose and fermi ideal gases immersed in periodic structures such as penetrable multilayers or multitubes simulated by one ( planes ) or two perpendicular ( tubes ) external dirac comb potentials , while the particles are allowed to move freely in the remaining directions . although the bosonic chemical potential is a constant for @xmath0 , a non decreasing with temperature anomalous behavior of the fermionic chemical potential is confirmed and monitored as the tube bundle goes from 2d to 1d when the wall impenetrability overcomes a critical value . in the specific heat curves dimensional crossovers are very noticeable at high temperatures for both gases , where the system behavior goes from 3d to 2d and latter to 1d as the wall impenetrability is increased .
| 133
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1109.0856
|
a framework for performing dynamic mesh adaptation with the discontinuous galerkin method ( dgm ) is presented . adaptations include modifications of the local mesh step size ( @xmath0-adaptation ) and the local degree of the approximating polynomials ( @xmath1-adaptation ) as well as their combination . the computation of the approximation within locally adapted elements is based on projections between finite element spaces ( fes ) , which are shown to preserve an upper limit of the electromagnetic energy . the formulation supports high level hanging nodes and applies precomputation of surface integrals for increasing computational efficiency . error and smoothness estimates based on interface jumps are presented and applied to the fully @xmath2-adaptive simulation of two examples in one - dimensional space . a full wave simulation of electromagnetic scattering form a radar reflector demonstrates the applicability to large scale problems in three - dimensional space . discontinuous galerkin method , dynamic mesh adaptation , @xmath2-adaptation , maxwell time - domain problem , large scale simulations 65m60 , 78a25
| 171
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1402.3379
|
employing graphites having distinctly different mean grain sizes , we study the effects of polycrystallinity on the pattern formation by ion - beam - sputtering . the grains influence the growth of the ripples in highly anisotropic fashion ; both the mean uninterrupted ripple length along its ridge and the surface width depend on the mean size of the grains , which is attributed to the large sputter yield at the grain boundary compared with that on terrace . in contrast , the ripple wavelength does not depend on the mean size of the grains . coarsening of the ripples - accompanying the mass transport across the grain boundaries - should not be driven by thermal diffusion , rather by ion - induced processes .
| 125
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1502.07007
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we report ultrafast transient - grating measurements of crystals of the three - dimensional dirac semimetal cadmium arsenide , cd@xmath0as@xmath1 , at both room temperature and 80 k. after photoexcitation with 1.5-ev photons , charge - carriers relax by two processes , one of duration 500 fs and the other of duration 3.1 ps . by measuring the complex phase of the change in reflectance , we determine that the faster signal corresponds to a decrease in absorption , and the slower signal to a decrease in the light s phase velocity , at the probe energy . we attribute these signals to electrons filling of phase space , first near the photon energy and later at lower energy . we attribute their decay to cooling by rapid emission of optical phonons , then slower emission of acoustic phonons . we also present evidence that both the electrons and the lattice are strongly heated . + + the following article appeared in _ applied physics letters _ and may be found at + http://scitation.aip.org/content/aip/journal/apl/106/23/10.1063/1.4922528 + ( this version of the article differs slightly from the published one . ) + + _ copyright 2015 american institute of physics . this article may be downloaded for personal use only . any other use requires prior permission of the author and the american institute of physics . _
| 226
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cond-mat0611568
|
we analyze a controversial topic about the universality class of the three - dimensional ising model with long - range - correlated disorder . whereas both theoretical and numerical studies agree on the validity of extended harris criterion ( a. weinrib , b.i . halperin , phys . rev . b 27 ( 1983 ) 413 ) and indicate the existence of a new universality class , the numerical values of the critical exponents found so far differ essentially . to resolve this discrepancy we perform extensive monte carlo simulations of a 3d ising model with non - magnetic impurities being arranged in a form of lines along randomly chosen axes of a lattice . the swendsen - wang algorithm is used alongside with a histogram reweighting technique and the finite - size scaling analysis to evaluate the values of critical exponents governing the magnetic phase transition . our estimates for these exponents differ from both previous numerical simulations and are in favour of a non - trivial dependency of the critical exponents on the peculiarities of long - range correlations decay . , , , random ising model , long - range - correlated disorder , monte carlo , critical exponents 05.10.ln , 64.60.fr , 75.10.hk
| 207
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astro-ph9706021
|
we report on observations of the x - ray pulsar by the lecs instrument on - board _ bepposax_. we confirm the recent asca discovery of excess emission near 1 kev ( angelini et al . 1995 ) . the pulse period of 7.66794 @xmath0 0.00004 s indicates that the source continues to spin - down . the phase averaged spectrum is well fit by an absorbed power - law of photon index 0.61 @xmath0 0.02 and a blackbody of temperature 0.33 @xmath0 0.02 kev , together with an emission feature at 1.05 @xmath0 0.02 kev . this spectral shape is similar to that observed by asca during the spin - down phase , but significantly different from measurements during spin - up . this suggests that the change in spectrum observed by asca may be a stable feature during spin - down intervals . the source intensity is a factor @xmath12 lower than observed by asca three years earlier , confirming that continues to become fainter with time .
| 170
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1608.02386
|
we demonstrate the use of several code implementations of the mellin - barnes method available in the public domain to derive analytic expressions for the sunset diagrams that arise in the two - loop contribution to the pion mass and decay constant in three - flavoured chiral perturbation theory . we also provide results for all possible two - mass configurations of the sunset integral , and derive a new one - dimensional integral representation for the one mass sunset integral with arbitrary external momentum . thoroughly annotated mathematica notebooks are provided as ancillary files , which may serve as pedagogical supplements to the methods described in this paper . lu tp 16 - 43 + august 2016 * an analytic approach to sunset diagrams in chiral perturbation theory : theory and practice * + @xmath0 centre for high energy physics , indian institute of science , + bangalore-560012 , karnataka , india + @xmath1department of astronomy and theoretical physics , lund university , + slvegatan 14a , se 223 - 62 lund , sweden + @xmath2department of physics and astronomy , university of delaware , + newark , de 19716 , usa +
| 194
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hep-th0409256
|
the @xmath0 liouville theory has received some attention recently as the euclidean version of an exact rolling tachyon background . in an earlier paper it was shown that the bulk theory can be identified with the interacting @xmath0 limit of unitary minimal models . here we extend the analysis of the @xmath0-limit to the boundary problem . most importantly , we show that the fzzt branes of liouville theory give rise to a new 1-parameter family of boundary theories at @xmath0 . these models share many features with the boundary sine - gordon theory , in particular they possess an open string spectrum with band - gaps of finite width . we propose explicit formulas for the boundary 2-point function and for the bulk - boundary operator product expansion in the @xmath0 boundary liouville model . as a by - product of our analysis we also provide a nice geometric interpretation for zz branes and their relation with fzzt branes in the @xmath0 theory .
| 165
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quant-ph0308104
|
we analyze the quantum walk on a cycle using discrete wigner functions as a way to represent the states and the evolution of the walker . the method provides some insight on the nature of the interference effects that make quantum and classical walks different . we also study the behavior of the system when the quantum coin carried by the walker interacts with an environment . we show that for this system quantum coherence is robust for initially delocalized states of the walker . the use of phase - space representation enables us to develop an intuitive description of the nature of the decoherence process in this system .
| 110
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astro-ph0408293
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we explore consequences of a radiation driven disk wind model for mass outflows from active galactic nuclei ( agn ) . we performed axisymmetric time - dependent hydrodynamic calculations using the same computational technique as proga , stone and kallman ( 2000 ) . we test the robustness of radiation launching and acceleration of the wind for relatively unfavorable conditions . in particular , we take into account the central engine radiation as a source of ionizing photons but neglect its contribution to the radiation force . additionally , we account for the attenuation of the x - ray radiation by computing the x - ray optical depth in the radial direction assuming that only electron scattering contributes to the opacity . our new simulations confirm the main result from our previous work : the disk atmosphere can shield itself from external x - rays so that the local disk radiation can launch gas off the disk photosphere . we also find that the local disk force suffices to accelerate the disk wind to high velocities in the radial direction . this is true provided the wind does not change significantly the geometry of the disk radiation by continuum scattering and absorption processes ; we discuss plausibility of this requirement . synthetic profiles of a typical resonance ultraviolet line predicted by our models are consistent with observations of broad absorption line ( bal ) qsos .
| 236
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1001.3274
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based on 3d hydrodynamical model atmospheres computed with the co@xmath0bold code and 3d non - lte ( nlte ) line formation calculations , we study the effect of the convection - induced line asymmetry on the derived @xmath1li abundance for a range in effective temperature , gravity , and metallicity covering the stars of the ( * ? ? ? * asplund ( 2006 ) ) sample . when the asymmetry effect is taken into account for this sample of stars , the resulting @xmath1li/@xmath2li ratios are reduced by about 1.5% on average with respect to the isotopic ratios determined by ( * ? ? ? * asplund ( 2006 ) ) . this purely theoretical correction diminishes the number of significant @xmath1li detections from 9 to 4 ( 2@xmath3 criterion ) , or from 5 to 2 ( 3@xmath3 criterion ) . in view of this result the existence of a @xmath1li plateau appears questionable . a careful reanalysis of individual objects by fitting the observed lithium @xmath4 doublet both with 3d nlte and 1d lte synthetic line profiles confirms that the inferred @xmath1li abundance is systematically lower when using 3d nlte instead of 1d lte line fitting . nevertheless , halo stars with unquestionable @xmath1li detection do exist even if analyzed in 3d - nlte , the most prominent example being hd84937 .
| 225
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astro-ph0102449
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the smallest polyatomic carbon chain , c@xmath0 , has been identified in interstellar clouds ( a@xmath11 mag ) towards @xmath2 ophiuchi , 20 aquilae , and @xmath2 persei by detection of the origin band in its @xmath3 electronic transition , near 4052 . individual rotational lines were resolved up to @xmath4=30 enabling the rotational level column densities and temperature distributions to be determined . the inferred limits for the total column densities ( @xmath51 to 2@xmath6 @xmath7 ) offer a strong incentive to laboratory and astrophysical searches for the longer carbon chains . concurrent searches for c@xmath8 , c@xmath9 and c@xmath10 were negative but provide sensitive estimates for their maximum column densities .
| 113
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0803.1036
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we present an investigation for the generation of intense magnetic fields in dense plasmas with an anisotropic electron fermi - dirac distribution . for this purpose , we use a new linear dispersion relation for transverse waves in the wigner - maxwell dense quantum plasma system . numerical analysis of the dispersion relation reveals the scaling of the growth rate as a function of the fermi energy and the temperature anisotropy . the nonlinear saturation level of the magnetic fields is found through fully kinetic simulations , which indicates that the final amplitudes of the magnetic fields are proportional to the linear growth rate of the instability . the present results are important for understanding the origin of intense magnetic fields in dense fermionic plasmas , such as those in the next generation intense laser - solid density plasma experiments .
| 141
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0710.4278
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we present a novel method for reconstructing the shape of an object from measured gradient data . a certain class of optical sensors does not measure the shape of an object , but its local slope . these sensors display several advantages , including high information efficiency , sensitivity , and robustness . for many applications , however , it is necessary to acquire the shape , which must be calculated from the slopes by numerical integration . existing integration techniques show drawbacks that render them unusable in many cases . our method is based on approximation employing radial basis functions . it can be applied to irregularly sampled , noisy , and incomplete data , and it reconstructs surfaces both locally and globally with high accuracy .
| 128
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1510.08838
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assume that we are given a closed chord - generic legendrian submanifold @xmath0 of the contactisation of a liouville manifold , where @xmath1 moreover admits an exact lagrangian filling @xmath2 inside the symplectisation . under the further assumptions that this filling is spin and has vanishing maslov class , we prove that the number of reeb chords on @xmath1 is bounded from below by the stable morse number of @xmath3 . given a general exact lagrangian filling @xmath3 , we show that the number of reeb chords is bounded from below by a quantity depending on the homotopy type of @xmath3 , following ono - pajitnov s implementation in floer homology of invariants due to sharko . this improves previously known bounds in terms of the betti numbers of either @xmath1 or @xmath3 .
| 134
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1307.1846
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we study the effects of chromoelectric and chromomagnetic dipole moments ( cedm and cmdm ) on the production cross section of single top @xmath0-channel at the lhc based on the effective lagrangian approach . we show that the impact of cedm and cmdm could be large . using the experimental measurement of the @xmath0-channel cross section , constraints on cedm and cmdm are extracted . these constraints are comparable with the ones obtained from the top pair analysis . 0.65 cm 0.5 cm * seyed yaser ayazi , hoda hesari and mojtaba mohammadi najafabadi*0.5 cm school of particles and accelerators , institute for research in fundamental sciences ( ipm ) , p.o . box 19395 - 5531 , tehran , iran
| 121
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1204.5530
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we introduce four basic two - dimensional ( 2d ) plaquette configurations with onsite cubic nonlinearities , which may be used as building blocks for 2d @xmath0-symmetric lattices . for each configuration , we develop a dynamical model and examine its @xmath1symmetry . the corresponding nonlinear modes are analyzed starting from the hamiltonian limit , with zero value of the gain - loss coefficient , @xmath2 . once the relevant waveforms have been identified ( chiefly , in an analytical form ) , their stability is examined by means of linearization in the vicinity of stationary points . this reveals diverse and , occasionally , fairly complex bifurcations . the evolution of unstable modes is explored by means of direct simulations . in particular , stable localized modes are found in these systems , although the majority of identified solutions is unstable .
| 143
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0806.1819
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this paper presents a low - ml - decoding - complexity , full - rate , full - diversity space - time block code ( stbc ) for a @xmath0 transmit antenna , @xmath0 receive antenna multiple - input multiple - output ( mimo ) system , with coding gain equal to that of the best and well known golden code for any qam constellation . recently , two codes have been proposed ( by paredes , gershman and alkhansari and by sezginer and sari ) , which enjoy a lower decoding complexity relative to the golden code , but have lesser coding gain . the @xmath1 stbc presented in this paper has lesser decoding complexity for non - square qam constellations , compared with that of the golden code , while having the same decoding complexity for square qam constellations . compared with the paredes - gershman - alkhansari and sezginer - sari codes , the proposed code has the same decoding complexity for non - rectangular qam constellations . simulation results , which compare the codeword error rate ( cer ) performance , are presented .
| 188
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astro-ph0112064
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we present the results of a joint investigation aimed at constraining the primordial he content ( @xmath0 ) on the basis of both the cosmic microwave background ( cmb ) anisotropy and two stellar observables , namely the tip of the red giant branch ( trgb ) and the luminosity of the zero age horizontal branch ( zahb ) . current baryon density estimates based on cmb measurements cover a wide range values @xmath1 , that according to big bang nucleosynthesis ( bbn ) models would imply @xmath2 . we constructed several sets of evolutionary tracks and hb models by adopting @xmath3 and several metal contents . the comparison between theory and observations suggests that zahb magnitudes based on he - enhanced models are 1.5@xmath4 brighter than the empirical ones . the same outcome applies for the trgb bolometric magnitudes . this finding somewhat supports a @xmath0 abundance close to the canonical 0.23 - 0.24 value . more quantitative constraints on this parameter are hampered by the fact that the cmb pattern shows a sizable dependence on both @xmath0 and the baryon density only at small angular scales , i.e. at high @xmath5 in the power spectrum ( @xmath6 ) . however , this region of the power spectrum could be still affected by deceptive systematic uncertainties . finally , we suggest to use the _ uv - upturn _ to estimate the he content on gpc scales . in fact , we find that a strong increase in @xmath0 causes in metal - poor , hot hb structures a decrease in the uv emission .
| 266
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1305.3736
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we study diffusive electron - electron interaction correction to conductivity by analyzing simultaneously @xmath0 and @xmath1 for disordered 2d electron systems in si in tilted magnetic field . tilting the field is shown to be a straightforward tool to disentangle spin and orbital effects . in particular , by changing the tilt angle we prove experimentally that in the field range @xmath2 the correction depends on modulus of magnetic field rather than on its direction , which is expected for a system with isotropic @xmath3-factor . in the high - field limit the correction behaves as @xmath4 , as expected theoretically ( lee , ramakrishnan , phys . rev . b*26 * , 4009 ( 1982 ) ) . our data prove that the diffusive electron - electron interaction correction to conductivity is not solely responsible for the huge and temperature dependent magnetoresistance in parallel field , typically observed in si - mosfets .
| 154
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1210.5540
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cataclysmic variables ( cvs ) are binaries in which a compact white dwarf accretes material from a low - mass companion star . the discovery of two planets in orbit around the cv hu aquarii opens unusual opportunities for understanding the formation and evolution of this system . in particular the orbital parameters of the planets constrains the past and enables us to reconstruct the evolution of the system through the common - envelope phase . during this dramatic event the entire hydrogen envelope of the primary star is ejected , passing the two planets on the way . the observed eccentricities and orbital separations of the planets in hu aqr enable us to limit the common - envelope parameter @xmath0 or @xmath1 and measure the rate at which the common envelope is ejected , which turns out to be copious . the mass in the common envelope is ejected from the binary system at a rate of @xmath2 . the reconstruction of the initial conditions for hu aqr indicates that the primary star had a mass of @xmath3 and a @xmath4 companion in a @xmath5160 ( best value @xmath6 ) binary . the two planets were born with an orbital separation of @xmath7 and @xmath8 respectively . after the common envelope , the primary star turns into a @xmath9 helium white dwarf , which subsequently accreted @xmath10 from its roche - lobe filling companion star , grinding it down to its current observed mass of @xmath11 . methods : numerical planets and satellites : dynamical evolution and stability planet star interactions planets and satellites : formation stars : individual : hu aquarius stars : binaries : evolution
| 278
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astro-ph0407438
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we present single - dish h spectra obtained with the green bank telescope , along with optical photometric properties from the sloan digital sky survey , of 20 nearby ( d @xmath0 70 mpc ) luminous compact blue galaxies ( lcbgs ) . these @xmath1l@xmath2 , blue , high surface brightness , starbursting galaxies were selected with the same criteria used to define lcbgs at higher redshifts . we find these galaxies are gas - rich , with m@xmath3 ranging from 5@xmath410@xmath5 to 8@xmath410@xmath6 m@xmath7 , and m@xmath3 l@xmath8 ranging from 0.2 to 2 m@xmath7 l@xmath9 , consistent with a variety of morphological types of galaxies . we find the dynamical masses ( measured within r@xmath10 ) span a wide range , from 3@xmath410@xmath6 to 1@xmath410@xmath11 m@xmath7 . however , at least half have dynamical mass - to - light ratios smaller than nearby galaxies of all hubble types , as found for lcbgs at intermediate redshifts . by comparing line widths and effective radii with local galaxy populations , we find that lcbgs are consistent with the dynamical mass properties of magellanic ( low luminosity ) spirals , and the more massive irregulars and dwarf ellipticals , such as ngc 205 .
| 203
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astro-ph0601446
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period - colour ( pc ) and amplitude - colour ( ac ) relations are studied for the large magellanic cloud ( lmc ) cepheids under the theoretical framework of the hydrogen ionization front ( hif ) - photosphere interaction . lmc models are constructed with pulsation codes that include turbulent convection , and the properties of these models are studied at maximum , mean and minimum light . as with galactic models , at maximum light the photosphere is located next to the hif for the lmc models . however very different behavior is found at minimum light . the long period ( @xmath0days ) lmc models imply that the photosphere is disengaged from the hif at minimum light , similar to the galactic models , but there are some indications that the photosphere is located near the hif for the short period ( @xmath1 days ) lmc models . we also use the updated lmc data to derive empirical pc and ac relations at these phases . our numerical models are broadly consistent with our theory and the observed data , though we discuss some caveats in the paper . we apply the idea of the hif - photosphere interaction to explain recent suggestions that the lmc period - luminosity ( pl ) and pc relations are non - linear with a break at a period close to 10 days . our empirical lmc pc and pl relations are also found to be non - linear with the @xmath2-test . our explanation relies on the properties of the saha ionization equation , the hif - photosphere interaction and the way this interaction changes with the phase of pulsation and metallicity to produce the observed changes in the lmc pc and pl relations . cepheids stars : fundamental parameters
| 300
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cond-mat0001260
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the c - axis charge dynamics of copper oxide materials in the underdoped and optimally doped regimes has been studied by considering the incoherent interlayer hopping . it is shown that the c - axis charge dynamics for the chain copper oxide materials is mainly governed by the scattering from the in - plane fluctuation , and the c - axis charge dynamics for the no - chain copper oxide materials is dominated by the scattering from the in - plane fluctuation incorporating with the interlayer disorder , which would be suppressed when the holon pseudogap opens at low temperatures and lower doping levels , leading to the crossovers to the semiconducting - like range in the c - axis resistivity and the temperature linear to the nonlinear range in the in - plane resistivity .
| 136
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1503.03569
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collimator angle is usually rotated when planning volumetric modulated arc therapy ( vmat ) due to the leakage of radiation between multi - leaf collimator ( mlc ) leaves . we studied the effect of the collimator angles on the results of dosimetric verification of the vmat plans for head and neck patients . we studied vmat plans for 10 head and neck patients . we made 2 sets of vmat plans for each patient . each set was composed of 10 plans with collimator angles of 0 , 5 , 10 , 15 , 20 , 25 , 30 , 35 , 40 , 45 degrees . plans in the first set were optimized individually and plans in the second set shared the 30 degree collimator angle optimization . two sets of plans were verified using the 2-dimensional ion chamber array matrixx ( iba dosimetry , germany ) . the comparison between the calculation and measurements were made by the @xmath0-index analysis . the @xmath0-index ( 2%/2 mm ) and ( 3%/3 mm ) passing rates had negative correlations with the collimator angle . maximum difference between @xmath0-index ( 3%/3 mm ) passing rates of different collimator angles for each patient ranged from 1.46% to 5.60% with an average of 3.67% . there were significant differences ( maximum 5.6% ) in the passing rates of different collimator angles . the results suggested that the accuracy of the delivered dose depends on the collimator angle . these findings are informative when choosing a collimator angle in vmat plans .
| 259
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1304.7281
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we present the single - epoch black hole mass estimators based on the @xmath01549 broad emission line , using the updated sample of the reverberation - mapped agns and high - quality uv spectra . by performing multi - component spectral fitting analysis , we measure the line widths ( fwhm@xmath1 and line dispersion , @xmath2 ) and the continuum luminosity at 1350 ( @xmath3 ) to calibrate the -based mass estimators . by comparing with the h@xmath4 reverberation - based masses , we provide new mass estimators with the best - fit relationships , i.e. , @xmath5 and @xmath6 . the new -based mass estimators show significant mass - dependent systematic difference compared to the estimators commonly used in the literature . using the published sloan digital sky survey qso catalog , we show that the black hole mass of high - redshift qsos decreases on average by @xmath7 dex if our recipe is adopted .
| 157
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cond-mat0602662
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measurements with an atomic force microscope ( afm ) offer a direct way to probe elastic properties of lipid bilayer membranes locally : provided the underlying stress - strain relation is known , material parameters such as surface tension or bending rigidity may be deduced . in a recent experiment a pore - spanning membrane was poked with an afm tip , yielding a linear behavior of the force - indentation curves . a theoretical model for this case is presented here which describes these curves in the framework of helfrich theory . the linear behavior of the measurements is reproduced if one neglects the influence of adhesion between tip and membrane . including it via an adhesion balance changes the situation significantly : force - distance curves cease to be linear , hysteresis and nonzero detachment forces can show up . the characteristics of this rich scenario are discussed in detail in this article .
| 156
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astro-ph9809224
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we present a new optical tully - fisher ( tf ) investigation for a complete , full - sky sample of 297 sb@xmath0sc spirals with redshifts between 4500 and 7000 . the survey was specifically designed to provide _ uniform , well - calibrated _ data over both hemispheres . all previous tf surveys within the supergalactic shell ( @xmath1 ) have relied on matching separate data sets in the northern and southern hemispheres and thus can not attain full - sky homogeneity . analyses of the cosmological dipole and peculiar velocities based on these studies have produced contradictory claims for the amplitude of the bulk flow and whether it is generated by internal or external mass fluctuations . with shellflow , and further zero - point calibration of existing tf data sets , we expect a high - accuracy detection of the bulk flow amplitude and an unambiguous characterization of the tidal field at 6000 . # 1#1@xmath2
| 159
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1308.4514
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mnge has been grown as a thin film on si(111 ) substrates by molecular beam epitaxy . a 10 layer of mnsi was used as seedlayer in order to establish the b20 crystal structure . films of a thickness between 45 and 135 have been prepared and structually characterized by rheed , afm and xrd . these techniques give evidence that mnge forms in the cubic b20 crystal structure as islands exhibiting a very smooth surface . the islands become larger with increasing film thickness . a magnetic characterization reveals that the ordering temperature of mnge thin films is enhanced compared to bulk material . the properties of the helical magnetic structure obtained from magnetization and magnetoresistivity measurements are compared with films of the related compound mnsi . the much larger dzyaloshinskii - moriya interaction in mnge results in a higher rigidness of the spin helix .
| 147
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astro-ph0302524
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we estimate the neutrino emission from individual gamma - ray bursts observed by the batse detector on the compton gamma - ray observatory . neutrinos are produced by photoproduction of pions when protons interact with photons in the region where the kinetic energy of the relativistic fireball is dissipated allowing the acceleration of electrons and protons . we also consider models where neutrinos are predominantly produced on the radiation surrounding the newly formed black hole . from the observed redshift and photon flux of each individual burst , we compute the neutrino flux in a variety of models based on the assumption that equal kinetic energy is dissipated into electrons and protons . where not measured , the redshift is estimated by other methods . unlike previous calculations of the universal diffuse neutrino flux produced by all gamma - ray bursts , the individual fluxes ( compiled at http://www.arcetri.astro.it/@xmath0 dafne / grb/ ) can be directly compared with coincident observations by the amanda telescope at the south pole . because of its large statistics , our predictions are likely to be representative for future observations with larger neutrino telescopes .
| 190
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1109.5792
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we point out that a non - overlapping well ( at negative energies ) adjacent to a finite barrier ( at positive energies ) is a simple potential which is generally missed out while discussing the one - dimensional potentials in the textbooks of quantum mechanics . we show that these systems present interesting situations wherein transmitivity @xmath0 of a finite barrier can be changed both quantitatively and qualitatively by varying the depth or width of the well or by changing the distance between the well and the barrier . using delta ( thin ) well near a delta ( thin ) barrier we show that the well induces energy oscillations riding over @xmath1 in the transmitivity @xmath2 at both the energies below and above the barrier . more generally we show that a thick well separated from a thick barrier also gives rise to energy oscillations in @xmath2 . a well joining a barrier discontinuously ( a finite jump ) reduces @xmath2 ( as compared to @xmath3 over all energies . when the well and barrier are joined continuously , @xmath2 increases and then decreases at energies below the barrier . at energy above the the barrier the changes are inappreciable . in these two cases if we separate the well and the barrier by a distance , @xmath2 again acquires oscillations . paradoxically , it turns out that a distant well induces more energy oscillations in @xmath2 than when it is near the barrier .
| 247
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astro-ph0509729
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it has been hypothesized recently that core collapse supernovae are triggered by mildly relativistic jets following observations of radio properties of these explosions . association of a jet , similar to a gamma - ray burst jet but only slower , allows shock acceleration of particles to high energy and non - thermal neutrino emission from a supernova . detection of these high energy neutrinos in upcoming kilometer scale cherenkov detectors may be the only direct way to probe inside these astrophysical phenomena as electromagnetic radiation is thermal and contains little information . calculation of high energy neutrino signal from a simple and slow jet model buried inside the pre - supernova star is reviewed here . the detection prospect of these neutrinos in water or ice detector is also discussed in this brief review . jetted core collapse supernovae in nearby galaxies may provide the strongest high energy neutrino signal from point sources .
| 155
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1407.4233
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we determine the intrinsic , 3-dimensional shape distribution of star - forming galaxies at @xmath0 , as inferred from their observed projected axis ratios . in the present - day universe star - forming galaxies of all masses @xmath1 are predominantly thin , nearly oblate disks , in line with previous studies . we now extend this to higher redshifts , and find that among massive galaxies ( @xmath2 ) disks are the most common geometric shape at all @xmath3 . lower - mass galaxies at @xmath4 possess a broad range of geometric shapes : the fraction of elongated ( prolate ) galaxies increases toward higher redshifts and lower masses . galaxies with stellar mass @xmath5 ( @xmath6 ) are a mix of roughly equal numbers of elongated and disk galaxies at @xmath7 ( @xmath8 ) . this suggests that galaxies in this mass range do not yet have disks that are sustained over many orbital periods , implying that galaxies with present - day stellar mass comparable to that of the milky way typically first formed such sustained stellar disks at redshift @xmath9 . combined with constraints on the evolution of the star formation rate density and the distribution of star formation over galaxies with different masses , our findings imply that , averaged over cosmic time , the majority of stars formed in disks .
| 227
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1203.0871
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we examine the relationship between dependence logic and game logics . a variant of dynamic game logic , called _ transition logic _ , is developed , and we show that its relationship with dependence logic is comparable to the one between first - order logic and dynamic game logic discussed by van benthem . this suggests a new perspective on the interpretation of dependence logic formulas , in terms of assertions about _ reachability _ in games of imperfect information against nature . we then capitalize on this intuition by developing expressively equivalent variants of dependence logic in which this interpretation is taken to the foreground .
| 108
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1211.2140
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in this work we study thermal leptogenesis using non - equilibrium quantum field theory . starting from fundamental equations for correlators of the quantum fields we describe the steps necessary to obtain quantum kinetic equations for quasiparticles . these can easily be compared to conventional results and overcome conceptional problems inherent in the canonical approach . beyond _ cp_-violating decays we include also those scattering processes which are tightly related to the decays in a consistent approximation of fourth order in the yukawa couplings . it is demonstrated explicitly how the s - matrix elements for the scattering processes in the conventional approach are related to two- and three - loop contributions to the effective action . we derive effective decay and scattering amplitudes taking medium corrections and thermal masses into account . in this context we also investigate _ cp_-violating higgs decay within the same formalism . from the kinetic equations we derive rate equations for the lepton asymmetry improved in that they include quantum - statistical effects and medium corrections to the quasiparticle properties .
| 177
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1603.01749
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here we report on the translocation of folded polymers through nano - pores using molecular dynamic simulations . two cases are studied ; one in which a folded molecule unfolds upon passage and one in which the folding remains intact as the molecule passes through the nano - pore . the topology of a folded polymer chain is defined as the arrangement of the intramolecular contacts , known as circuit topology . in the case where intramolecular contacts remain intact , we show that the dynamics of passage through a nano - pore varies for molecules with differing topologies : a phenomenon that can be exploited to enrich certain topologies in mixtures . we find that the nano - pore allows reading of topology for short chains . moreover , when the passage is coupled with unfolding , the nano - pore enables discrimination between pure states , i.e. , states for which the majority of contacts are arranged identically . in this case , as we show here , it is also possible to read the positions of the contact sites along a chain . our results demonstrate the applicability of nano - pore technology to characterize and sort molecules based on their topology .
| 206
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0910.5023
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measurements of small - scale turbulent fluctuations in the solar wind find a non - zero right - handed magnetic helicity . this has been interpreted as evidence for ion cyclotron damping . however , theoretical and empirical evidence suggests that the majority of the energy in solar wind turbulence resides in low frequency anisotropic kinetic alfvn wave fluctuations that are not subject to ion cyclotron damping . we demonstrate that a dissipation range comprised of kinetic alfvn waves also produces a net right - handed fluctuating magnetic helicity signature consistent with observations . thus , the observed magnetic helicity signature does not necessarily imply that ion cyclotron damping is energetically important in the solar wind .
| 117
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1508.05576
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the phase behavior of asymmetrically interacting abc star triblock copolymer melts is investigated by the self - consistent field theory ( scft ) . motivated by the experimental systems , in this study , we focus on the systems in which the flory - huggins interaction parameters satisfy @xmath0 . using various initialization strategies , a large number of periodic structures have been obtained in our calculations . a fourth - order pseudospectral algorithm combined with anderson mixing method is used to compute the free energy of candidate structures carefully . the stability has been detailedly analyzed by splitting the free energy into internal and entropic parts . a complete and complex triangular phase diagram is presented for a model with @xmath1 in which fifteen ordered phases , including two- , and three - dimensional structures , have been predicted to be stable from the scft calculations . generally speaking , with the asymmetrical interactions , the hierarchical structures tend to be formed near the b - rich corner of the triangular phase diagram . this work broadens the previous theoretical results from equal interaction systems to unequal interaction systems . the predicted phase behavior is in good agreement with experimental observations and previous theoretical results .
| 207
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1203.6238
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the conductance profiles of magnetic transition metal atoms , such as fe , co and mn , deposited on surfaces and probed by a scanning tunneling microscope ( stm ) , provide detailed information on the magnetic excitations of such nano - magnets . in general the profiles are symmetric with respect to the applied bias . however a set of recent experiments has shown evidence for inherent asymmetries when either a normal or a spin - polarized stm tip is used . in order to explain such asymmetries here we expand our previously developed perturbative approach to electron - spin scattering to the spin - polarized case and to the inclusion of out of equilibrium spin populations . in the case of a magnetic stm tip we demonstrate that the asymmetries are driven by the non - equilibrium occupation of the various atomic spin - levels , an effect that reminds closely that electron spin - transfer . in contrast when the tip is not spin - polarized such non - equilibrium population can not be build up . in this circumstance we propose that the asymmetry simply originates from the transition metal ion density of state , which is included here as a non - vanishing real component to the spin - scattering self - energy .
| 219
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1409.3511
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the core entropy of polynomials , recently introduced by w. thurston , is a dynamical invariant which can be defined purely in combinatorial terms , and provides a useful tool to study parameter spaces of polynomials . the theory of core entropy extends to complex polynomials the entropy theory for real unimodal maps : the real segment is replaced by an invariant tree , known as hubbard tree , which lives inside the filled julia set . we prove that the core entropy of quadratic polynomials varies continuously as a function of the external angle , answering a question of thurston .
| 102
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gr-qc9906066
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we develop the canonical formalism for a system of @xmath0 bodies in lineal gravity and obtain exact solutions to the equations of motion for @xmath1 . the determining equation of the hamiltonian is derived in the form of a transcendental equation , which leads to the exact hamiltonian to infinite order of the gravitational coupling constant . in the equal mass case explicit expressions of the trajectories of the particles are given as the functions of the proper time , which show characteristic features of the motion depending on the strength of gravity ( mass ) and the magnitude and sign of the cosmological constant . as expected , we find that a positive cosmological constant has a repulsive effect on the motion , while a negative one has an attractive effect . however , some surprising features emerge that are absent for vanishing cosmological constant . for a certain range of the negative cosmological constant the motion shows a double maximum behavior as a combined result of an induced momentum - dependent cosmological potential and the gravitational attraction between the particles . for a positive cosmological constant , not only bounded motions but also unbounded ones are realized . the change of the metric along the movement of the particles is also exactly derived . * exact solutions of relativistic two - body motion in lineal gravity * + r.b . mann and d. robbins + dept . of physics , university of waterloo waterloo , ont n2l 3g1 , canada + and + t. ohta + department of physics , miyagi university of education , aoba - aramaki , sendai 980 , japan + pacs numbers : 13.15.-f , 14.60.gh , 04.80.+z + +
| 286
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cond-mat0602181
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first - principles , density - functional - based electronic structure calculations are employed to study the changes in the electronic properties of @xmath0 and @xmath1 using the korringa - kohn - rostoker coherent - potential approximation method in the atomic sphere approximation ( kkr - asa cpa ) . as a function of decreasing @xmath2 @xmath3% , we find a steady decrease in the lattice constant and bulk modulus in either alloys . however , the pressure derivative of the bulk modulus displays an opposite trend . following the debye model , which relates the pressure derivative of the bulk modulus with the average phonon frequency of the crystal , it can thus be argued that @xmath4 and its disordered alloys posses a different phonon spectra in comparison to its @xmath5 counterparts . this is further justified by the marked similarity we find in the electronic structure properties such as the variation in the density of states and the hopfield parameters calculated for these alloys . the effects on the equation of state parameters and the density of states at the fermi energy , for partial replacement of @xmath6 by @xmath7 are also discussed .
| 196
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0909.2908
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quick chemical equilibration times of hadrons ( specifically , @xmath0 , @xmath1 , @xmath2 , and @xmath3 pairs ) within a hadron gas are explained dynamically using hagedorn states , which drive particles into equilibrium close to the critical temperature . within this scheme , we use master equations and derive various analytical estimates for the chemical equilibration times . we compare our model to recent lattice results and find that for both @xmath4 mev and @xmath5 mev , the hadrons can reach chemical equilibrium almost immediately , well before the chemical freeze - out temperatures found in thermal fits for a hadron gas without hagedorn states . furthermore the ratios @xmath6 , @xmath7 , @xmath8 , and @xmath9 match experimental values well in our dynamical scenario .
| 128
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math0503576
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we consider the simple random walk on the ( unique ) infinite cluster of super - critical bond percolation in @xmath0 with @xmath1 . we prove that , for almost every percolation configuration , the path distribution of the walk converges weakly to that of non - degenerate , isotropic brownian motion . our analysis is based on the consideration of a harmonic deformation of the infinite cluster on which the random walk becomes a square - integrable martingale . the size of the deformation , expressed by the so called corrector , is estimated by means of ergodicity arguments . = 1
| 103
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astro-ph0511683
|
resonance scattering has often been invoked to explain the disagreement between the observed and predicted line ratios of @xmath015.01 to @xmath015.26 ( the `` 3c/3d '' ratio ) . in this process photons of @xmath015.01 , with its much higher oscillator strength , are preferentially scattered out of the line of sight , thus reducing the observed line ratio . recent laboratory measurements , however , have found significant inner - shell lines at 15.21 and 15.26 , suggesting that the observed 3c/3d ratio results from blending . given our new understanding of the fundamental spectroscopy , we have re - examined the original solar spectra , identifying the @xmath015.21 line and measuring its flux to account for the contribution of to the @xmath015.26 flux . deblending brings the 3c/3d ratio into good agreement with the experimental ratio ; hence , we find no need to invoke resonance scattering . low opacity in @xmath015.01 also implies low opacity for fe xv @xmath0284.2 , ruling out resonance scattering as the cause of the fuzziness of and -eit 284 images . the images must , instead , be unresolved due to the large number of structures at this temperature . insignificant resonance scattering implies that future instruments with higher spatial resolution could resolve the active region plasma into its component loop structures .
| 221
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hep-ph9412246
|
within the framework of the operator product expansion ( ope ) and the renormalization group equation ( rge ) , we show that the temperature and chemical potential dependence of the zeroth moment of a spectral function ( sf ) is completely determined by the one - loop structure in an asymptotically free theory , and in particular in qcd . logarithmic corrections are found to play an essential role in the derivation . this exact result constrains the shape of sf s , and implies striking effects near phase transitions . phenomenological parameterizations of the sf , often used in applications such as the analysis of lattice qcd data or qcd sum rule calculations at finite temperature and baryon density must satisfy these constraints . we also explicitly illustrate in detail the exact sum rule in the gross - neveu model .
| 143
|
1308.4974
|
we present results from high - resolution hydrodynamic simulations of isolated smc- and milky way - sized galaxies that include a model for feedback from galactic cosmic rays ( crs ) . we find that crs are naturally able to drive winds with mass loading factors of up to @xmath0 in dwarf systems . the scaling of the mass loading factor with circular velocity between the two simulated systems is consistent with @xmath1 required to reproduce the faint end of the galaxy luminosity function . in addition , simulations with cr feedback reproduce both the normalization and the slope of the observed trend of wind velocity with galaxy circular velocity . we find that winds in simulations with cr feedback exhibit qualitatively different properties compared to sn driven winds , where most of acceleration happens violently in situ near star forming sites . the cr - driven winds are accelerated gently by the large - scale pressure gradient established by crs diffusing from the star - forming galaxy disk out into the halo . the cr - driven winds also exhibit much cooler temperatures and , in the smc - sized system , warm ( @xmath2 k ) gas dominates the outflow . the prevalence of warm gas in such outflows may provide a clue as to the origin of ubiquitous warm gas in the gaseous halos of galaxies detected via absorption lines in quasar spectra .
| 237
|
1611.08650
|
we introduce a novel class of interaction - enabled topological crystalline insulators in two- and three - dimensional electronic systems , which we call `` topological crystalline magnet . '' it is protected by the product of the time - reversal symmetry @xmath0 and a mirror symmetry or a rotation symmetry @xmath1 . a topological crystalline magnet exhibits two intriguing features : ( i ) it can not be adiabatically connected to any slater insulator and ( ii ) the edge state is robust against coupling electrons to the edge . these features are protected by the anomalous symmetry transformation property @xmath2 of the edge state . an anisotropic response to the external magnetic field can be an experimental signature .
| 121
|
1307.1812
|
so far analysis of the quasinormal spectrum of a massive charged scalar field in the black hole background has been limited by the regime of small @xmath0 and @xmath1 , where @xmath2 , @xmath3 ( @xmath4 , @xmath5 ) are mass and charge of the field ( black hole ) . here we shall present a comprehensive picture of quasinormal modes , late - time tails and stability of a massive charged scalar field around kerr - newman black holes for any physically meaningful values of the parameters . we shall show that despite presence of the two mechanisms of superradiance ( owing to black hole s rotation and charge ) and the massive term creating growing bound states , there is no indication of instability under quasinormal modes boundary conditions . we have shown that for some moderate values of @xmath1 dominant quasinormal modes may have _ arbitrarily small real oscillation frequencies _ @xmath6 . an analytic formula for the quasinormal modes has been derived in the regime of large @xmath1 . the larger the field s charge , the sooner asymptotic tails dominate in a signal , making it difficult to extract quasinormal frequencies from a time - domain profile . analytic expressions for intermediate and asymptotically late - time tails have been found for the reissner - nordstrm black hole . for the near extremal kerr - newman black holes we have obtained a more general picture of the _ mode branching _ found recently for massless fields ( arxiv:1212.3271 ) in the kerr background .
| 259
|
astro-ph0610909
|
we present a deep image of the radio galaxy mrc 1138262 taken with the _ hubble space telescope ( hst ) _ at a redshift of @xmath0 . the galaxy is known to have properties of a cd galaxy progenitor and be surrounded by a 3 mpc - sized structure , identified with a protocluster . the morphology shown on the new deep _ hst _ acs image is reminiscent of a spider s web . more than 10 individual clumpy features are observed , apparently star - forming satellite galaxies in the process of merging with the progenitor of a dominant cluster galaxy 11 gyr ago . there is an extended emission component , implying that star formation was occurring over a 50@xmath140 kpc region at a rate of more than 100 @xmath2 yr@xmath3 . a striking feature of the newly named `` spiderweb galaxy '' is the presence of several faint linear galaxies within the merging structure . the dense environments and fast galaxy motions at the centres of protoclusters may stimulate the formation of these structures , which dominate the faint resolved galaxy populations in the hubble ultra deep field . the new image provides a unique testbed for simulations of forming dominant cluster galaxies .
| 209
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1107.2548
|
helicity and @xmath0 effect driven by the nonaxisymmetric tayler instability of toroidal magnetic fields in stellar radiation zones are computed . in the linear approximation a purely toroidal field always excites pairs of modes with identical growth rates but with opposite helicity so that the net helicity vanishes . if the magnetic background field has a helical structure by an extra ( weak ) poloidal component then one of the modes dominates producing a net kinetic helicity anticorrelated to the current helicity of the background field . + the mean electromotive force is computed with the result that the @xmath0 effect by the most rapidly growing mode has the same sign as the current helicity of the background field . the @xmath0 effect is found as too small to drive an @xmath1 dynamo but the excitation conditions for an @xmath2 dynamo can be fulfilled for weak poloidal fields . moreover , if the dynamo produces its own @xmath0 effect by the magnetic instability then problems with its sign do not arise . for all cases , however , the @xmath0 effect shows an extremely strong concentration to the poles so that a possible @xmath2 dynamo might only work at the polar regions . hence , the results of our linear theory lead to a new topological problem for the existence of large - scale dynamos in stellar radiation zones on the basis of the current - driven instability of toroidal fields . [ firstpage ] magnetohydrodynamics ( mhd ) instabilities stars : magnetic fields stars : interiors .
| 258
|
astro-ph0302392
|
we describe the first results of a programme to obtain rotation curves of @xmath0 disc galaxies in the near - infrared using the h@xmath1 emission line in order to study the tully - fisher relationship . to put any observed evolution into perspective and to investigate any possible selection biases , we constructed a control sample of low redshift galaxies that had rotation velocities and images available for measuring their dynamical , photometric , and morphological properties . compared to local objects with isophotal sizes similar to the high redshift targets , we find that our sample of galaxies with spatially resolved rotation curves , the most distant sample so far ( @xmath2 ) , clearly reveals a brightening of @xmath3 mag in the rest - frame b - band . the observed offset can be explained by a combination of increasing surface brightness , decreasing rotation speeds , and slightly smaller disc scale lengths of the high redshift galaxies .
| 161
|
astro-ph0309377
|
we report on the properties of nuclear regions in the toomre sequence of merging galaxies , based on imaging data gathered with the _ hubble space telescope _ wfpc2 camera . we have imaged the 11 systems in the proposed evolutionary merger sequence in the f555w and f814w broad - band filters , and in h@xmath0 + [ ] narrow - band filters . the broad - band morphology of the nuclear regions varies from non - nucleated starburst clumps through dust - covered nuclei to a nucleated morphology . there is no unambiguous trend in the morphology with merger stage . the emission - line morphology is extended beyond the nucleus in most cases , but centrally concentrated ( within 1 kpc ) emission - line gas can be seen in the four latest - stage merger systems . we have quantified the intrinsic luminosity densities and colors within the inner 100 pc and 1 kpc of each identified nucleus . we find little evidence for a clear trend in nuclear properties along the merger sequence , other than a suggestive rise in the nuclear luminosity density in the most evolved members of the sequence . the lack of clear trends in nuclear properties is likely due both to the effects of obscuration and geometry , as well as the physical variety of galaxies included in the toomre sequence .
| 231
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math0612266
|
let @xmath0 be a connected , semisimple lie group with finite center and let @xmath1 be a maximal compact subgroup . we investigate a method to compute multiplicities of @xmath1-types in the discrete series using a rational expression for a generating function obtained from blattner s formula . this expression involves a product with a character of an irreducible finite dimensional representation of @xmath1 and is valid for any discrete series system . other results include a new proof of a symmetry of blattner s formula , and a positivity result for certain low rank examples . we consider in detail the situation for @xmath0 of type split @xmath2 . the motivation for this work came from an attempt to understand pictures coming from blattner s formula , some of which we include in the paper .
| 137
|
0707.4390
|
the experimental demonstration of the modification of the casimir force between a gold coated sphere and a single - crystal si membrane by light pulses is performed . the specially designed and fabricated si membrane was irradiated with 514 nm laser pulses of 5ms width in high vacuum leading to a change of the charge - carrier density . the difference in the casimir force in the presence and in the absence of laser radiation was measured by means of an atomic force microscope as a function of separation at different powers of the absorbed light . the total experimental error of the measured force differences at a separation of 100 nm varies from 10 to 20% in different measurements . the experimental results are compared with theoretical computations using the lifshitz theory at both zero and laboratory temperatures . the total theoretical error determined mostly by the uncertainty in the concentration of charge carriers when the light is incident is found to be about 14% at separations less than 140 nm . the experimental data are consistent with the lifshitz theory at laboratory temperature , if the static dielectric permittivity of high - resistivity si in the absence of light is assumed to be finite . if the dc conductivity of high - resistivity si in the absence of light is included into the model of dielectric response , the lifshitz theory at nonzero temperature is shown to be experimentally inconsistent at 95% confidence . the demonstrated phenomenon of the modification of the casimir force through a change of the charge - carrier density is topical for applications of the lifshitz theory to real materials in fields ranging from nanotechnology and condensed matter physics to the theory of fundamental interactions .
| 292
|
1108.5056
|
we present an updated version of skirt , a 3d monte carlo radiative transfer code developed to simulate dusty galaxies . the main novel characteristics of the skirt code are the use of a stellar foam to generate random positions , an efficient combination of eternal forced scattering and continuous absorption , and a new library approach that links the radiative transfer code to the dustem dust emission library . this approach enables a fast , accurate and self - consistent calculation of the dust emission of arbitrary mixtures of transiently heated dust grains and polycyclic aromatic hydrocarbons , even for full 3d models containing millions of dust cells . we have demonstrated the accuracy of the skirt code through a set of simulations based on the edge - on spiral galaxy ugc4754 . the models we ran were gradually refined from a smooth , 2d , lte model to a fully 3d model that includes nlte dust emission and a clumpy structure of the dusty ism . we find that clumpy models absorb uv and optical radiation less efficiently than smooth models with the same amount of dust , and that the dust in clumpy models is on average both cooler and less luminous . our simulations demonstrate that , given the appropriate use of optimization techniques , it is possible to efficiently and accurately run monte carlo radiative transfer simulations of arbitrary 3d structures of several million dust cells , including a full calculation of the nlte emission by arbitrary dust mixtures .
| 255
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math0611336
|
can boutet de monvel s algebra on a compact manifold with boundary be obtained as the algebra @xmath0 of pseudodifferential operators on some lie groupoid @xmath1 ? if it could , the kernel @xmath2 of the principal symbol homomorphism would be isomorphic to the groupoid @xmath3 . while the answer to the above question remains open , we exhibit in this paper a groupoid @xmath1 such that @xmath3 possesses an ideal @xmath4 isomorphic to @xmath2 . in fact , we prove first that @xmath5 with the @xmath6-algebra @xmath7 generated by the zero order pseudodifferential operators on the boundary and the algebra @xmath8 of compact operators . as both @xmath9 and @xmath10 are extensions of @xmath11 by @xmath12 ( @xmath13 is the co - sphere bundle over the boundary ) we infer from a theorem by voiculescu that both are isomorphic .
| 141
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astro-ph0208477
|
we present the first results from 60ks of observations of arp 220 using the acis - s instrument on chandra . we report the detection of several sources near the galaxy s nucleus , including a point source with a hard spectrum that is coincident with the western radio nucleus b. this point source is mildly absorbed ( @xmath0 ) and has an estimated luminosity of @xmath1 erg / s . in addition , a fainter source may coincide with the eastern nucleus a. extended hard x - ray emission in the vicinity raises the total estimated nuclear 2 - 10 kev x - ray luminosity to @xmath2 erg / s , but we can not rule out a hidden agn behind columns exceeding @xmath3 we also detect a peak of soft x - ray emission to the west of the nucleus , and a hard point source 2.5 kpc from the nucleus with a luminosity of @xmath4 erg / s .
| 162
|
1209.0549
|
we introduce a novel multiobjective optimization algorithm based on the conformational space annealing ( csa ) algorithm , mocsa . it has three characteristic features : ( a ) dominance relationship and distance between solutions in the objective space are used as the fitness measure , ( b ) update rules are based on the fitness as well as the distance between solutions in the decision space and ( c ) it uses a constrained local minimizer . we have tested mocsa on 12 test problems , consisting of zdt and dtlz test suites . benchmark results show that solutions obtained by mocsa are closer to the pareto front and covers a wider range of the objective space than those by the elitist non - dominated sorting genetic system ( nsga2 ) . conformational space annealing , multiobjective optimization , genetic algorithm , evolutionary algorithm , pareto front
| 148
|
1603.08734
|
we present a theoretical study of the dissociative tunneling ionization process . analytic expressions for the nuclear kinetic energy distribution of the ionization rates are derived . a particularly simple expression for the spectrum is found by using the born - oppenheimer ( bo ) approximation in conjunction with the reflection principle . these spectra are compared to exact non - bo _ ab initio _ spectra obtained through model calculations with a quantum mechanical treatment of both the electronic and nuclear degrees freedom . in the regime where the bo approximation is applicable imaging of the bo nuclear wave function is demonstrated to be possible through reverse use of the reflection principle , when accounting appropriately for the electronic ionization rate . a qualitative difference between the exact and bo wave functions in the asymptotic region of large electronic distances is shown . additionally the behavior of the wave function across the turning line is seen to be reminiscent of light refraction . for weak fields , where the bo approximation does not apply , the weak - field asymptotic theory describes the spectrum accurately .
| 187
|
1305.6233
|
the liouville - lanczos approach to linear - response time - dependent density - functional theory is generalized so as to encompass electron energy - loss and inelastic x - ray scattering spectroscopies in periodic solids . the computation of virtual orbitals and the manipulation of large matrices are avoided by adopting a representation of response orbitals borrowed from ( time - independent ) density - functional perturbation theory and a suitable lanczos recursion scheme . the latter allows the bulk of the numerical work to be performed at any given transferred momentum only once , for a whole extended frequency range . the numerical complexity of the method is thus greatly reduced , making the computation of the loss function over a wide frequency range at any given transferred momentum only slightly more expensive than a single standard ground - state calculation , and opening the way to computations for systems of unprecedented size and complexity . our method is validated on the paradigmatic examples of bulk silicon and aluminum , for which both experimental and theoretical results already exist in the literature .
| 185
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nucl-th0307075
|
a method is presented to obtain the canonical - form solutions of the hfb equation for atomic nuclei with zero - range interactions like the skyrme force . it is appropriate to describe pairing correlations in the continuum in coordinate - space representations . an improved gradient method is used for faster convergences under constraint of orthogonality between orbitals . to prevent high - lying orbitals to shrink into a spatial point , a repulsive momentum dependent force is introduced , which turns out to unveil the nature of high - lying canonical - basis orbitals . the asymptotic properties at large radius and the relation with quasiparticle states are discussed for the obtained canonical basis .
| 117
|
astro-ph0112469
|
it is believed that orphan afterglow searches can help to measure the beaming angle in gamma - ray bursts ( grbs ) . great expectations have been put on this method . we point out that the method is in fact not as simple as we originally expected . due to the baryon - rich environment that is common to almost all popular progenitor models , there should be many failed gamma - ray bursts , i.e. , fireballs with lorentz factor much less than 100 1000 , but still much larger than unity . in fact , the number of failed gamma - ray bursts may even be much larger than that of successful bursts . owing to the existence of these failed gamma - ray bursts , there should be many orphan afterglows even if grbs are due to isotropic fireballs , then the simple discovery of orphan afterglows never means that grbs be collimated . unfortunately , to distinguish a failed - grb orphan and a jetted but off - axis grb orphan is not an easy task . the major problem is that the trigger time is unknown . some possible solutions to the problem are suggested . = -0.5 in stars : neutron ism : jets and outflows gamma - rays : bursts
| 218
|
1006.5578
|
we consider the supersymmetric extension of the standard model with neutrino yukawa interactions and @xmath0-parity violation . we found that @xmath0-parity breaking term @xmath1 leads to an additional @xmath2-type contribution to the higgs scalar potential , and thus to the masses of supersymmetric higgs bosons . the most interesting consequence is the modification of the tree - level expression for the lightest neutral supersymmetric higgs boson mass . it appears that due to this contribution the bound on the lightest higgs mass may be shifted upwards , thus slightly opening the part of the model parameter space excluded by non - observation of the light higgs boson at lep in the framework of the minimal supersymmetric standard model .
| 119
|
0802.0073
|
two numerical strategies based on the wang - landau and lee entropic sampling schemes are implemented to investigate the first - order transition features of the 3d bimodal ( @xmath0 ) random - field ising model at the strong disorder regime . we consider simple cubic lattices with linear sizes in the range @xmath1 and simulate the system for two values of the disorder strength : @xmath2 and @xmath3 . the nature of the transition is elucidated by applying the lee - kosterlitz free - energy barrier method . our results indicate that , despite the strong first - order - like characteristics , the transition remains continuous , in disagreement with the early mean - field theory prediction of a tricritical point at high values of the random - field . _ keywords _ : bimodal random - field ising model , wang - landau sampling , free - energy barrier method
| 153
|
astro-ph0402277
|
extensive time - resolved observations of kuiper belt object 2001 qg@xmath0 show a lightcurve with a peak - to - peak variation of @xmath1 magnitudes and single - peaked period of @xmath2 hr . the mean absolute magnitude is 6.85 magnitudes which corresponds to a mean effective radius of 122 ( 77 ) km if an albedo of 0.04 ( 0.10 ) is assumed . this is the first known kuiper belt object and only the third minor planet with a radius @xmath3 25 km to display a lightcurve with a range in excess of 1 magnitude . we find the colors to be typical for a kuiper belt object ( @xmath4 , @xmath5 ) with no variation in color between minimum and maximum light . the large light variation , relatively long double - peaked period and absence of rotational color change argue against explanations due to albedo markings or elongation due to high angular momentum . instead , we suggest that 2001 qg@xmath0 may be a very close or contact binary similar in structure to what has been independently proposed for the trojan asteroid 624 hektor . if so , its rotational period would be twice the lightcurve period or @xmath6 hr . by correcting for the effects of projection , we estimate that the fraction of similar objects in the kuiper belt is at least @xmath710% to 20% with the true fraction probably much higher . a high abundance of close and contact binaries is expected in some scenarios for the evolution of binary kuiper belt objects .
| 261
|
1511.03636
|
we generalize the classical one dimensional potts model to the case where the symmetry group is a non - abelian finite group . it turns out that this new model has a quantum nature in that its spectrum of energy eigenstates consists of entangled states . we determine the complete energy spectrum , i.e. the ground states and all the excited states with their degeneracy structure . we calculate the partition function by two different algebraic and combinatorial methods . we also determine the entanglement properties of its ground states . * the quantum ( non - abelian ) potts model and its exact solution * 4em * razieh mohseninia * and * vahid karimipour * 1em department of physics , + sharif university of technology , p.o . box 111555 - 9161 , tehran , iran . + pacs numbers : 05.50.+q , 64.60.de , 75.10.-b , 75.10.hk , 03.65.ud
| 151
|
cond-mat0402294
|
the scaling of the tails of the probability of a system to percolate only in the horizontal direction @xmath0 was investigated numerically for correlated site - bond percolation model for @xmath1 . we have to demonstrate that the tails of the crossing probability far from the critical point @xmath2 have shape @xmath3^{\nu})$ ] where @xmath4 is the correlation length index , @xmath5 is the probability of a bond to be closed . at criticality we observe crossover to another scaling @xmath6^{\nu } \right\}^{z } \right)$ ] . here @xmath7 is a scaling index describing the central part of the crossing probability .
| 102
|
astro-ph9704166
|
in this paper , we extend previous work on the absorption of high energy @xmath0-rays in intergalactic space by calculating the absorption of 10 to 500 gev @xmath0-rays at high redshifts . this calculation requires the determination of the high - redshift evolution of the intergalactic starlight photon field , including its spectral energy distribution out to frequencies beyond the lyman limit . to estimate this evolution , we have followed a recent analysis of fall , charlot & pei , which reproduces the redshift dependence of the starlight background emissivity obtained by the canada - france redshift survey group . we also include the uv background from quasars . we give our results for the @xmath0-ray opacity as a function of redshift out to a redshift of 3 . we also give predicted @xmath0-ray spectra for selected blazars and extend our calculations of the extragalactic @xmath0-ray background from blazars to an energy of 500 gev with absorption effects included . our results indicate that the extragalactic @xmath0-ray background spectrum from blazars should steepen significantly above 20 gev , owing to extragalactic absorption . future observations of a such a steepening would thus provide a test of the blazar origin hypothesis for the @xmath0-ray background radiation . we also note that our absorption calculations can be used to place limits on the redshifts of @xmath0-ray bursts ; for example , our calculated opacities indicate that the 17 feb . 1994 burst observed by _ egret _ must have originated at @xmath1 . finally , our estimates of the high - energy @xmath0-ray background spectrum are used to determine the observability of multi - gev @xmath0-ray lines from the annihilation of supersymmetric dark - matter particles in the galactic halo .
| 290
|
astro-ph0205208
|
we present the _ xmm - newton _ observations of x - ray afterglows of the @xmath0-ray bursts grb 011211 and grb 001025 . for grb 011211 _ xmm _ detected fading x - ray object with an average flux in 0.2 - 10 kev declining from @xmath1 erg @xmath2 s@xmath3 during the first 5 ks of 27-ks observation to @xmath4 erg @xmath2 s@xmath3 toward the end of the observation . the spectrum of the afterglow can be fit to a power law with @xmath5=2.16@xmath60.03 modified for the galactic absorption . no significant evolution of spectral parameters has been detected during the observation . similar x - ray spectrum with @xmath5=2.01@xmath60.09 has been observed by the xmm from the grb 001025 . the non - detection of any extra absorption in these spectra above the galactic value is an interesting fact and may impose restrictions to the favorable grb models involving burst origin in star - forming regions . finally we discuss soft x - ray lines from grb 011211 reported by reeves et al . and conclude that there is no definitive evidence for the presense of these lines in the spectrum . * # 1#1
| 197
|
1306.4105
|
transport measurements were performed on the organic layered compound 3 under hydrostatic pressure . the carrier types , densities and mobilities are determined from the magneto - conductance of 3 . while evidence of high - mobility massless dirac carriers has already been given , we report here , their coexistence with low - mobility massive holes . this coexistence seems robust as it has been found up to the highest studied pressure . our results are in agreement with recent dft calculations of the band structure of this system under hydrostatic pressure . a comparison with graphene dirac carriers has also been done . 3 @xmath0 2 @xmath1
| 109
|
1006.4566
|
we study a two - point self - avoidance energy @xmath0 which is defined for all rectifiable curves in @xmath1 as the double integral along the curve of @xmath2 . here @xmath3 stands for the radius of the ( smallest ) circle that is tangent to the curve at one point and passes through another point on the curve , with obvious natural modifications of this definition in the exceptional , non - generic cases . it turns out that finiteness of @xmath4 for @xmath5 guarantees that @xmath6 has no self - intersections or triple junctions and therefore must be homeomorphic to the unit circle @xmath7 or to a closed interval @xmath8 . for @xmath9 the energy @xmath0 evaluated on curves in @xmath10 turns out to be a knot energy separating different knot types by infinite energy barriers and bounding the number of knot types below a given energy value . we also establish an explicit upper bound on the hausdorff - distance of two curves in @xmath10 with finite @xmath0-energy that guarantees that these curves are ambient isotopic . this bound depends only on @xmath11 and the energy values of the curves . moreover , for all @xmath11 that are larger than the critical exponent @xmath12 , the arclength parametrization of @xmath6 is of class @xmath13 , with hlder norm of the unit tangent depending only on @xmath11 , the length of @xmath6 , and the local energy . the exponent @xmath14 is optimal .
| 246
|
0808.2187
|
we construct effective 2- and 3-body hamiltonians for the p - shell by performing @xmath0 _ ab initio _ no - core shell model ( ncsm ) calculations for a=6 and 7 nuclei and explicitly projecting the many - body hamiltonians onto the @xmath1 space . we then separate these effective hamiltonians into 0- , 1- and 2-body contributions ( also 3-body for a=7 ) and analyze the systematic behavior of these different parts as a function of the mass number a and size of the ncsm basis space . the role of effective 3- and higher - body interactions for @xmath2 is investigated and discussed .
| 107
|
1609.00814
|
for sequences of random backward nested subspaces as occur , say , in dimension reduction for manifold or stratified space valued data , asymptotic results are derived . in fact , we formulate our results more generally for backward nested families of descriptors ( bnfd ) . under rather general conditions , asymptotic strong consistency holds . under additional , still rather general hypotheses , among them existence of a.s . local twice differentiable charts , asymptotic joint normality of a bnfd can be shown . if charts factor suitably , this leads to individual asymptotic normality for the last element , a principal nested mean or a principal nested geodesic , say . it turns out that these results pertain to principal nested spheres ( pns ) and principal nested great subsphere ( pngs ) analysis by @xcite as well as to the intrinsic mean on a first geodesic principal component ( imo1gpc ) for manifolds and kendall s shape spaces . a nested bootstrap two - sample test is derived and illustrated with simulations . in a study on real data , pngs is applied to track early human mesenchymal stem cell differentiation over a coarse time grid and , among others , to locate a change point with direct consequences for the design of further studies . _ keywords : _ frchet means , dimension reduction on manifolds , principal nested spheres , asymptotic consistency and normality , geodesic principal component analysis , kendall s shape spaces , flags of subspaces _ ams subject classifications : _ primary 62g20 , 62g25 . secondary 62h11 , 58c06 , 60d05 .
| 272
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