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0904.3704
|
* gaia - ca - tn - lo - sz-002 - 2 * issue 2 , numerical integration of the differential equations of light propagation in the schwarzschild metric shows that in some extreme situations relevant for practical observations ( e.g. for gaia ) the well - known standard post - newtonian formula for the boundary problem has an error up to 16 . the aim of this note is to identify the reason for this error and to derive an extended formula accurate at the level of 1 as needed e.g. for gaia . the analytical parametrized post - post - newtonian solution for light propagation derived by @xcite gives the solution for the boundary problem with all analytical terms of order @xmath0 taken into account . giving an analytical upper estimates of each term we investigate which post - post - newtonian terms may play a role for an observer in the solar system at the level of 1 . we conclude that only one post - post - newtonian term remains important for this numerical accuracy and derive a simplified analytical solution for the boundary problem for light propagation containing all the terms that are indeed relevant at the level of 1 . the derived analytical solution has been verified using the results of a high - accuracy numerical integration of differential equations of light propagation and found to be correct at the level well below 1 for arbitrary observer situated within the solar system .
| 249
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1109.0426
|
we study the parameter dependence of the internal structure of resonance states by formulating complex two - dimensional ( 2d ) matrix model , where the two dimensions represent two - levels of resonances . we calculate a critical value of the parameter at which `` nature transition '' with character exchange occurs between two resonance states , from the viewpoint of geometry on complex - parameter space . such critical value is useful to know the internal structure of resonance states with variation of the parameter in the system . we apply the model to analyze the internal structure of hadrons with variation of the color number @xmath0 from @xmath1 to a realistic value @xmath2 . by regarding @xmath3 as the variable parameter in our model , we calculate a critical color number of nature transition between hadronic states in terms of quark - antiquark pair and mesonic molecule as exotics from the geometry on complex-@xmath0 plane . for the large-@xmath0 effective theory , we employ the chiral lagrangian induced by holographic qcd with d4/d8/@xmath4 multi - d brane system in the type iia superstring theory .
| 188
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cond-mat0503624
|
the effects of regular s=1 dilution of s=1/2 isotropic antiferromagnetic chain are investigated by the quantum monte carlo loop / cluster algorithm . our numerical results show that there are two kinds of ground - state phases which alternate with the variation of @xmath0 concentration . when the effective spin of a unit cell is half - integer , the ground state is ferrimagnetic with gapless energy spectrum and the magnetism becomes weaker with decreasing of the @xmath1 concentration @xmath2 . while it is integer , a non - magnetic ground state with gaped spectrum emerges and the gap gradually becomes narrowed as fitted by a relation of @xmath3 .
| 110
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hep-ph9301288
|
we calculate the gauge - boson pairs @xmath0 , @xmath1 , @xmath2 , @xmath3 productions in the @xmath4 collisions , where the photon beam is realized by the laser back - scattering method . these processes are important tests for the non - abelian gauge sector of the standard model ( sm ) . precise calculations of these processes can therefore probe the anomalous gauge - boson interactions . besides , these processes are important potential backgrounds for the intermediate mass higgs ( imh ) search in the @xmath5 production . = 10000 * @xmath6 , @xmath7 , @xmath8 and @xmath3 pair productions at tev @xmath9 colliders * dept . of physics & astronomy , northwestern university , evanston , illinois 60208 , usa +
| 125
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0705.2128
|
we consider a real - valued path ; it is possible to associate a tree to this path , and we explore the relations between the tree , the properties of of the path , and integration with respect to the path . in particular , the fractal dimension of the tree is estimated from the variations of the path , and young integrals with respect to the path , as well as integrals from the rough paths theory , are written as integrals on the tree . examples include some stochastic paths such as martingales , lvy processes and fractional brownian motions ( for which an estimator of the hurst parameter is given).=-1 . .
| 116
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hep-th0606256
|
we show that the entanglement entropy and alpha entropies corresponding to spatial polygonal sets in @xmath0 dimensions contain a term which scales logarithmically with the cutoff . its coefficient is a universal quantity consisting in a sum of contributions from the individual vertices . for a free scalar field this contribution is given by the trace anomaly in a three dimensional space with conical singularities located on the boundary of a plane angular sector . we find its analytic expression as a function of the angle . this is given in terms of the solution of a set of non linear ordinary differential equations . for general free fields , we also find the small - angle limit of the logarithmic coefficient , which is related to the two dimensional entropic c - functions . the calculation involves a reduction to a two dimensional problem , and as a byproduct , we obtain the trace of the green function for a massive scalar field in a sphere where boundary conditions are specified on a segment of a great circle . this also gives the exact expression for the entropies for a scalar field in a two dimensional de sitter space . keywords : entanglement entropy , conformal anomaly , three dimensional field theory . pacs : 03.70.+k , 03.65.ud , 04.62.+v , 05.50.+q
| 223
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0801.3065
|
this paper presents a cut - elimination proof for the logic @xmath0 , which is an extension of a proof system for encoding generic judgments , the logic @xmath1 of miller and tiu , with an induction principle . the logic @xmath0 , just as @xmath1 , features extensions of first - order intuitionistic logic with fixed points and a `` generic quantifier '' , @xmath2 , which is used to reason about the dynamics of bindings in object systems encoded in the logic . a previous attempt to extend @xmath1 with an induction principle has been unsuccessful in modeling some behaviours of bindings in inductive specifications . it turns out that this problem can be solved by relaxing some restrictions on @xmath2 , in particular by adding the axiom @xmath3 , where @xmath4 is not free in @xmath5 . we show that by adopting the equivariance principle , the presentation of the extended logic can be much simplified . this paper contains the technical proofs for the results stated in @xcite ; readers are encouraged to consult @xcite for motivations and examples for @xmath6
| 185
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1610.04801
|
we consider the survival probability @xmath0 of a random walk with a constant hopping rate @xmath1 on a host lattice of fractal dimension @xmath2 and spectral dimension @xmath3 , with spatially correlated traps . the traps form a sublattice with fractal dimension @xmath4 and are characterized by the absorption rate @xmath5 which may be finite ( imperfect traps ) or infinite ( perfect traps ) . initial coordinates are chosen randomly at or within a fixed distance of a trap . for weakly absorbing traps ( @xmath6 ) , we find that @xmath0 can be closely approximated by a stretched exponential function over the initial stage of relaxation , with stretching exponent @xmath7 , where @xmath8 is the random walk dimension of the host lattice . at the end of this initial stage there occurs a crossover to power law kinetics @xmath9 with the same exponent @xmath10 as for the stretched exponential regime . for strong absorption @xmath11 , including the limit of perfect traps @xmath12 , the stretched exponential regime is absent and the decay of @xmath0 follows , after a short transient , the aforementioned power law for all times .
| 193
|
physics0509009
|
we study the effect of interactions between objects floating at fluid interfaces , for the case in which the objects are primarily supported by surface tension . we give conditions on the density and size of these objects for equilibrium to be possible and show that two objects that float when well - separated may sink as the separation between the objects is decreased . finally , we examine the equilbrium of a raft of strips floating at an interface , and find that rafts of sufficiently low density may have infinite spatial extent , but that above a critical raft density , all rafts sink if they are sufficiently large . we compare our numerical and asymptotic results with some simple table - top experiments , and find good quantitative agreement .
| 133
|
gr-qc9805024
|
we generalise results of ford and roman which place lower bounds known as quantum inequalities on the renormalised energy density of a quantum field averaged against a choice of sampling function . ford and roman derived their results for a specific non - compactly supported sampling function ; here we use a different argument to obtain quantum inequalities for a class of smooth , even and non - negative sampling functions which are either compactly supported or decay rapidly at infinity . our results hold in @xmath0-dimensional minkowski space ( @xmath1 ) for the free real scalar field of mass @xmath2 . we discuss various features of our bounds in @xmath3 and @xmath4 dimensions . in particular , for massless field theory in @xmath3-dimensional minkowski space , we show that our quantum inequality is weaker than flanagan s optimal bound by a factor of @xmath5 . [ section ]
| 149
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1603.09034
|
metallic ni@xmath0v@xmath1 alloys are known to exhibit a ferromagnetic to paramagnetic disordered quantum phase transition ( qpt ) at the critical concentration @xmath2 0.114 in bulk . such a qpt is accompanied by a quantum griffiths phase ( qgp ) , the physical observables in which follow non - universal power - law temperature dependences , in a finite temperature range on the paramagnetic side of the transition . in the present work , we explore the occurrence of qgp in nanoparticles of this alloy system . nanoalloys with @xmath3 in the neighbourhood of @xmath4 and mean diameter 18 - 33 nm were prepared by a chemical reflux method . following a few microscopic and spectroscopic studies to determine the sizes , compositions and phases , dc magnetization measurements were also performed to seek out any signature of qgp in the nanoalloys . a paramagnetic - like increase of magnetization is observed to emerge below an @xmath3-dependent transition temperature @xmath5 within the blocked ferromagnetic state of the nanoparticles , and is corroborated by a peak at @xmath5 in the temperature dependence of resistivity . the magnetic susceptibility in this emergent phase follows a non - curie power - law temperature dependence below 10 k for @xmath6 , indicating the presence of a qgp in the nanoparticles within these temperature and composition ranges .
| 223
|
cond-mat0306607
|
it is known that the quantized vortices in a superfluid can be described by a dual electromagnetic model through the duality transformation . recently a new technique , which can selectively remove atoms from a bose - einstein condensate , was applied to the vortex lattice state of the rapid rotating boson gases . the increase of vortex number , dynamical formation of giant vortex , the oscillation and damping of vortex motion were observed in these experiments . in this paper we will discuss these observations in the framework of dual description and show how to understood these observations naturally .
| 102
|
1509.07507
|
the census of the solar neighborhood is almost complete for stars and becoming more complete in the brown dwarf regime . spectroscopic , photometric and kinematic characterization of nearby objects helps us to understand the local mass function , the binary fraction , and provides new targets for sensitive planet searches . we aim to derive spectral types and spectro - photometric distances of a sample of new high proper motion sources found with the wise satellite , and obtain parallaxes for those objects that fall within the area observed by the vista variables in the va lctea survey ( vvv ) . we used low resolution spectroscopy and template fitting to derive spectral types , multiwavelength photometry to characterize the companion candidates and obtain photometric distances . multi - epoch imaging from the vvv survey was used to measure the parallaxes and proper motions for three sources . we confirm a new t2 brown dwarf within @xmath015pc . we derived optical spectral types for twenty four sources , mostly m dwarfs within 50pc . we addressed the wide binary nature of sixteen objects found by the wise mission and previously known high proper motion sources . six of these are probably members of wide binaries , two of those are new , and present evidence against the physical binary nature of two candidate binary stars found in the literature , and eight that we selected as possible binary systems . we discuss a likely microlensing event produced by a nearby low mass star and a galaxy , that is to occur in the following five years . [ firstpage ] astrometry , parallaxes , binaries , brown dwarfs , techniques : spectroscopic .
| 284
|
1512.08727
|
in this talk , i present the minimal classically scale - invariant and @xmath0-symmetric extension of the standard model , containing one additional complex gauge singlet and three flavors of right - handed majorana neutrinos , incorporated within a renormalizable framework of gravity , consistent with these symmetries ; the agravity . i particularly focus on the slow - roll inflationary paradigm within this framework , by identifying the pseudo - nambu - goldstone boson of the ( approximate ) scale symmetry with the inflaton field , constructing its one - loop effective potential , computing the slow - roll parameters and the inflationary observables , and demonstrating the compatibility of the small field inflation scenario with the latest planck collaboration data sets .
| 124
|
1107.0493
|
we study the behavior of a real - valued and unobservable process @xmath0 under an extreme event of a related process @xmath1 that is observable . our analysis is motivated by the well - known garch model which represents two such sequences , i.e. the observable log returns of an asset as well as the hidden volatility process . our results complement the findings of segers [ j. segers , multivariate regular variation of heavy - tailed markov chains , arxiv : math/0701411 ( 2007 ) . available online : http://arxiv.org/abs/math/0701411 ] and smith [ r. l. smith , the extremal index for a markov chain . j. appl . prob . ( 1992 ) ] for a single time series . we show that under suitable assumptions their concept of a tail chain as a limiting process is also applicable to our setting . furthermore , we discuss existence and uniqueness of a limiting process under some weaker assumptions . finally , we apply our results to the garch@xmath2 case .
| 172
|
1302.4056
|
we study a planar two - temperature diffusion of a brownian particle in a parabolic potential . the diffusion process is defined in terms of two langevin equations with two different effective temperatures in the @xmath0 and the @xmath1 directions . in the stationary regime the system is described by a non - trivial particle position distribution @xmath2 , which we determine explicitly . we show that this distribution corresponds to a non - equilibrium stationary state , characterised by the presence of space - dependent particle currents which exhibit a non - zero rotor . theoretical results are confirmed by the numerical simulations . _ keywords _ : two - dimensional diffusion , parabolic potential , non - equilibrium stationary state , rotating flows
| 125
|
1411.7533
|
we consider downlink precoding in a frequency - selective multi - user massive mimo system with highly efficient but non - linear power amplifiers at the base station ( bs ) . a low - complexity precoding algorithm is proposed , which generates constant - envelope ( ce ) transmit signals for each bs antenna . to avoid large variations in the phase angle transmitted from each antenna , the difference of the phase angles transmitted in consecutive channel uses is limited to @xmath0 $ ] for a fixed @xmath1 . to achieve a desired per - user information rate , the extra total transmit power required under the time variation constraint when compared to the special case of no time variation constraint ( i.e. , @xmath2 ) , is _ small _ for many practical values of @xmath3 . in a i.i.d . rayleigh fading channel with @xmath4 bs antennas , @xmath5 single - antenna users and a desired per - user information rate of @xmath6 bit - per - channel - use , the extra total transmit power required is less than @xmath7 db when @xmath8 . massive mimo , constant envelope .
| 195
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astro-ph9808123
|
many nearby early - type ( elliptical and s0 ) galaxies contain weak ( milli - jansky level ) nuclear radio sources on scales a few hundred parsecs or less . the origin of the radio emission , however , has remained unclear , especially in volume - limited samples that select intrinsically less luminous galaxies . both active galactic nuclei and nuclear star formation have been suggested as possible mechanisms for producing the radio emission . this paper utilizes optical spectroscopic information to address this issue . a substantial fraction of the early - type galaxies surveyed with the very large array by wrobel & heeschen ( 1991 ) exhibits detectable optical emission lines in their nuclei down to very sensitive limits . comparison of the observed radio continuum power with that expected from the thermal gas traced by the optical emission lines implies that the bulk of the radio emission is nonthermal . both the incidence and the strength of optical line emission correlate with the radio power . at a fixed line luminosity , ellipticals have stronger radio cores than s0s . the relation between radio power and line emission observed in this sample is consistent with the low - luminosity extension of similar relations seen in classical radio galaxies and luminous seyfert nuclei . a plausible interpretation of this result is that the weak nuclear sources in nearby early - type galaxies are the low - luminosity counterparts of more powerful agns . the spectroscopic evidence supports this picture . most of the emission - line objects are optically classified as seyfert nuclei or low - ionization nuclear emission - line regions ( liners ) , the majority of which are likely to be accretion - powered sources .
| 293
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astro-ph9610091
|
0.4 cm we describe the bayesian - based signal - to - noise eigenmode method for cosmological parameter estimation , show how it can be used to optimally compress large cmb anisotropy data sets to manageable sizes , and apply it to the dmr 4-year , south pole and saskatchewan data , individually and in combination . a simple prior probability method is used to include large scale structure observations . estimates of the hubble parameter , vacuum energy density , baryon fraction and primordial spectral tilt derived from the combined data are given . epsf # 1#23.6pt # 1@xmath0 ^ # 1#1 # 1#1 # 1#1 # 1#1 c 3mp@xmath1 m # 1to 0pt#1 @xmath2 canadian institute for theoretical astrophysics , toronto , ontario , canada . @xmath3 center for particle astrophysics , uc berkeley , berkeley ca usa .
| 141
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1612.08216
|
the localized low - energy interfacial excitations , or nambu - goldstone modes , of phase - segregated binary mixtures of bose - einstein condensates are investigated analytically by means of a double - parabola approximation ( dpa ) to the lagrangian density in gross - pitaevskii theory for a system in a uniform potential . within this model analytic expressions are obtained for the excitations underlying capillary waves or ripplons " for arbitrary strength @xmath0 of the phase segregation . the dispersion relation @xmath1 is derived directly from the bogoliubov - de gennes equations in limit that the wavelength @xmath2 is much larger than the healing length @xmath3 . the proportionality constant in the dispersion relation provides the static interfacial tension . a correction term in @xmath4 of order @xmath5 is calculated analytically , entailing a finite - wavelength correction factor @xmath6 . this prediction may be tested experimentally using ( quasi-)uniform optical - box traps . explicit expressions are obtained for the structural deformation of the interface due to the passing of the capillary wave . it is found that the amplitude of the wave is enhanced by an amount that is quadratic in the ratio of the phase velocity @xmath7 to the sound velocity @xmath8 . for generic asymmetric mixtures consisting of condensates with unequal healing lengths an additional modulation is predicted of the common value of the condensate densities at the interface .
| 237
|
1403.0191
|
the in - plane thermal conductivity of iron - based superconductor rbfe@xmath0as@xmath0 single crystal ( @xmath1 2.1 k ) was measured down to 100 mk . in zero field , the observation of a significant residual linear term @xmath2 = 0.65 mw k@xmath3 @xmath4 provides clear evidence for nodal superdonducting gap . the field dependence of @xmath2 is similar to that of its sister compound csfe@xmath0as@xmath0 with comparable residual resistivity @xmath5 , and lies between the dirty and clean kfe@xmath0as@xmath0 . these results suggest that the ( k , rb , cs)fe@xmath0as@xmath0 serial superconductors have a common nodal gap structure .
| 101
|
1611.04196
|
whenever we use devices to take measurements , calibration is indispensable . while the purpose of calibration is to reduce bias and uncertainty in the measurements , it can be quite difficult , expensive and sometimes even impossible to implement . we study a challenging problem called _ self - calibration _ , i.e. , the task of designing an algorithm for devices so that the algorithm is able to perform calibration automatically . more precisely , we consider the setup @xmath0 where only partial information about the sensing matrix @xmath1 is known and where @xmath1 linearly depends on @xmath2 . the goal is to estimate the calibration parameter @xmath2 ( resolve the uncertainty in the sensing process ) and the signal / object of interests @xmath3 simultaneously . for three different models of practical relevance we show how such a _ bilinear _ inverse problem , including blind deconvolution as an important example , can be solved via a simple _ linear least squares _ approach . as a consequence , the proposed algorithms are numerically extremely efficient , thus allowing for real - time deployment . explicit theoretical guarantees and stability theory are derived and the number of sampling complexity is nearly optimal ( up to a poly - log factor ) . applications in imaging sciences and signal processing are discussed and numerical simulations are presented to demonstrate the effectiveness and efficiency of our approach .
| 239
|
cond-mat0211314
|
we discuss the superfluid to mott - insulator transition of cold atoms in optical lattices recently observed by greiner et.al . ( nature 415 , 39 ( 2002 ) ) . the fundamental properties of both phases and their experimental signatures are discussed carefully , including the limitations of the standard gutzwiller - approximation . it is shown that in a one - dimensional dilute bose - gas with a strong transverse confinement ( tonks - gas ) , even an arbitrary weak optical lattice is able to induce a mott like state with crystalline order , provided the dimensionless interaction parameter is larger than a critical value of order one . the superfluid - insulator transition of the bose - hubbard model in this case continuously evolves into a transition of the commensurate- incommensurate type with decreasing strength of the external optical lattice .
| 145
|
0808.4152
|
a class of modified gravity , known as @xmath0-gravity , has presently been applied to cosmology as a realistic alternative to dark energy . in this paper we use the most recent type - ia supernova ( sne ia ) data , the so - called _ union _ sample of 307 sne ia , to place bounds on a theory of the form @xmath1 within the palatini approach . given the complementarity of sne ia data with other cosmological observables , a joint analysis with measurements of baryon acoustic oscillation peak and estimates of the cmb shift parameter is also performed . we show that , for the allowed intervals of @xmath2 , @xmath3 , and @xmath4 , models based on @xmath5 gravity in the palatini approach can produce the sequence of radiation - dominated , matter - dominated , and accelerating periods without need of dark energy .
| 150
|
1012.2849
|
a central assumption in our analysis of cosmic structure is that cosmological perturbations have zero ensemble mean . this property is one of the consequences of statistically homogeneity , the invariance of correlation functions under spatial translations . in this article we explore whether cosmological perturbations indeed have zero mean , and thus test one aspect of statistical homogeneity . we carry out a classical test of the zero mean hypothesis against a class of alternatives in which perturbations have non - vanishing means , but homogeneous and isotropic covariances . apart from gaussianity , our test does not make any additional assumptions about the nature of the perturbations and is thus rather generic and model - independent . the test statistic we employ is essentially student s @xmath0 statistic , applied to appropriately masked , foreground - cleaned cosmic microwave background anisotropy maps produced by the wmap mission . we find evidence for a non - zero mean in a particular range of multipoles , but the evidence against the zero mean hypothesis goes away when we correct for multiple testing . we also place constraints on the mean of the temperature multipoles as a function of angular scale . on angular scales smaller than four degrees , a non - zero mean has to be at least an order of magnitude smaller than the standard deviation of the temperature anisotropies .
| 233
|
math0509174
|
let @xmath0 be the set of all standard young tableaux with @xmath1 cells . after recalling the definitions of four partial orders , the weak , @xmath2 , geometric and chain orders on @xmath3 and some of their crucial properties , we prove three main results : 1 . intervals in any of these four orders essentially describe the product in a hopf algebra of tableaux defined by poirier and reutenauer . 2 . the map sending a tableau to its descent set induces a homotopy equivalence of the proper parts of all of these orders on tableaux with that of the boolean algebra @xmath4}$ ] . in particular , the mbius function of these orders on tableaux is @xmath5 . 3 . for two of the four orders , one can define a more general order on skew tableaux having fixed inner boundary , and similarly analyze their homotopy type and mbius function .
| 155
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hep-ph9912201
|
di - gluon fusion mechanism might account for the large branching ratios of @xmath0 . but because we know little about the effective @xmath1 vertex , there are large uncertainties in perturbative qcd estimations . in this paper , we try several kinds of @xmath1 form factors and compare the numerical results with the experiment . we find that , though we know little about @xmath1 form factor , if di - gluon fusion mechanism is important in @xmath0 , the branching ratios of the decays @xmath2 would be around @xmath3 which can be tested by future experiments . * pacs numbers 13.25.hw 13.20.he *
| 105
|
hep-lat0209164
|
we present results of a high - statistics study of scalar and pseudoscalar meson propagators in quenched qcd at two values of lattice spacing , @xmath0 and 5.9 , with clover - improved wilson fermions . the study of the chiral limit is facilitated by the pole - shifting ansatz of the modified quenched approximation . pseudoscalar masses and decay constants are determined as a function of quark mass and quenched chiral log effects are estimated . a study of the flavor singlet @xmath1 hairpin diagram yields a precise determination of the @xmath1 mass insertion . the corresponding value of the quenched chiral log parameter @xmath2 is compared with the observed qcl effects . removal of qcl effects from the scalar propagator allows a determination of the mass of the lowest lying isovector scalar @xmath3 meson .
| 137
|
quant-ph0408049
|
using gaussian wave packet solutions , we examine how the kinetic energy is distributed in time - dependent solutions of the schrdinger equation corresponding to the cases of a free particle , a particle undergoing uniform acceleration , a particle in a harmonic oscillator potential , and a system corresponding to an unstable equilibrium . we find , for specific choices of initial parameters , that as much as @xmath0 of the kinetic energy can be localized ( at least conceptually ) in the ` front half ' of such gaussian wave packets , and we visualize these effects .
| 100
|
1605.03422
|
we consider the curves whose all normal planes are at the same distance from a fixed point and obtain some characterizations of them in the 3-dimensional euclidean space . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ keywords : curve , plane curve , distance , spherical curve , involute . 2000 mathematics subject classification : 53a04 . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
| 182
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0712.3193
|
we discuss exclusive vector meson electroproduction within the qcd collinear factorization framework . in bjorken kinematics the amplitude factorizes in a convolution of the nonperturbative meson distribution amplitude and the generalized parton densities with the perturbatively calculable hard - scattering amplitudes , which are presently known to next - to - leading order ( nlo ) . at small @xmath0 nlo corrections are very large . it is related to appearance of bfkl type logarithms in the hard - scattering amplitudes , that calls for a resummation of these effects at higher orders . here we report the first results of such resummation .
| 104
|
cond-mat0408006
|
we present a systematic @xmath0 in nqr study on the heavy fermion compounds cerh@xmath1ir@xmath2in@xmath3 ( @xmath4=0.25 , 0.35 , 0.45 , 0.5 , 0.55 and 0.75 ) . the results provide strong evidence for the microscopic coexistence of antiferromagnetic ( af ) order and superconductivity ( sc ) in the range of 0.35 @xmath5 0.55 . specifically , for @xmath4=0.5 , @xmath6 is observed at 3 k with a subsequent onset of superconductivity at @xmath7=0.9 k. @xmath7 reaches a maximum ( 0.94 k ) at @xmath4=0.45 where @xmath6 is found to be the highest ( 4.0 k ) . detailed analysis of the measured spectra indicate that the same electrons participate in both sc and af order . the nuclear spin - lattice relaxation rate @xmath8 shows a broad peak at @xmath6 and follows a @xmath9 variation below @xmath7 , the latter property indicating unconventional sc as in ceirin@xmath3 ( @xmath7=0.4 k ) . we further find that , in the coexistence region , the @xmath9 dependence of @xmath8 is replaced by a @xmath10-linear variation below @xmath110.4 k , with the value @xmath12 increasing with decreasing @xmath4 , likely due to low - lying magnetic excitations associated with the coexisting magnetism .
| 202
|
1104.4364
|
let @xmath0 be a smooth quasi - projective variety of dimension @xmath1 , @xmath2 bloch s higher chow group , and @xmath3 the cycle class map . beilinson once conjectured @xmath4 to be surjective @xcite ; however jannsen was the first to find a counterexample in the case @xmath5 @xcite . in this paper we study the image of @xmath4 in more detail ( as well as at the `` generic point '' of @xmath6 ) in terms of kernels of abel - jacobi mappings . when @xmath7 , we deduce from the bloch - kato conjecture ( now a theorem ) various results , in particular that the cokernel of @xmath8 at the generic point is the same for integral or rational coefficients .
| 125
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1411.6783
|
we have performed a systematic study of @xmath0 and @xmath1 production in @xmath2 collisions at different lhc energies and at different rapidities using the leading order ( lo ) non - relativistic qcd ( nrqcd ) model of heavy quarkonium production . we have included the contributions from @xmath3 ( @xmath4 = 0 , 1 , 2 ) and @xmath1 decays to @xmath0 . the calculated values have been compared with the available data from the four experiments at lhc namely , alice , atlas , cms and lhcb . in case of alice , inclusive @xmath0 and @xmath1 cross - sections have been calculated by including the feed - down from @xmath5 meson using fixed - order next - to - leading logarithm ( fonll ) formalism . it is found that all the experimental cross - sections are well reproduced for @xmath6 4 gev within the theoretical uncertainties arising due to the choice of the factorization scale . we also predict the transverse momentum distributions of @xmath0 and @xmath1 both for the direct and feed - down processes at the upcoming lhc energies of @xmath7 5.1 tev and 13 tev for the year 2015 .
| 197
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1503.01828
|
spin exchange interaction between atoms in a spin-1 bose - einstein condensate causes atomic spin evolving periodically under the single spatial mode approximation in the mean field theory . by applying fast magnetic pulses according to a two - step or a four - step control protocol , we find analytically that the spin dynamics is significantly suppressed for an arbitrary initial state . numerical calculations under single mode approximation are carried out to confirm the validity and robustness of these protocols . this localization method can be readily utilized to improve the sensitivity of a magnetometer based on spin-1 bose - einstein condensates .
| 105
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1607.00886
|
we developed a graph - based method to solve the multi - objective optimization problem of minimizing or maximizing subsets of @xmath0 bounded variables under partial order constraints . this problem , motivated by the optimization of the response of multi - input monotone systems applied to biological gene networks , can find applications in other contexts such as task scheduling . we introduce a mapping between coloured graphs ( hasse diagrams ) and polytopes associated with an ideal point , and find an exact closed - form description of the pareto optimal set using a dynamic program based on edge contractions . the proof of the algorithm is based on decomposition properties of pareto optimal sets that follow from elementary set operations , notably a maximality property valid for compact ensembles . in the general case , the pareto front is found in @xmath1 steps , where @xmath0 is the number of variables and @xmath2 the number of faces of the pareto front . using a parameterized complexity approach , the computation and the representation of the solution reaches @xmath3 for series - parallel graphs when the size of monochromatic connected components is bounded .
| 196
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1102.4556
|
this paper is devoted to the study of traveling waves for monotone evolution systems of bistable type . under an abstract setting , we establish the existence of bistable traveling waves for discrete and continuous - time monotone semiflows . this result is then extended to the cases of periodic habitat and weak compactness , respectively . we also apply the developed theory to four classes of evolution systems . * keywords : * monotone semiflows , traveling waves , bistable dynamics , periodic habitat . * ams msc 2010 * : 37c65 , 35c07 , 35k55 , 35b40 .
| 100
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0912.2392
|
we study superconductivity in the two - dimensional 16-band @xmath0-@xmath1 model extracted from a tight - binding fit to the band structure of lafeaso , using the random phase approximation . when the intraorbital repulsion @xmath2 is larger than the interorbital one @xmath3 , an extended @xmath4-wave ( @xmath5-wave ) pairing with sign reversal of order parameter is mediated by antiferromagnetic spin fluctuations , while when @xmath6 another kind of @xmath4-wave ( @xmath7-wave ) pairing without sign reversal is mediated by ferro - orbital fluctuations . the @xmath7-wave pairing is enhanced due to the electron - phonon coupling and then can be expanded over the realistic parameter region with @xmath8 .
| 111
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0706.1827
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over the last decades strong efforts have been made to apply new spaceborne technologies to the study and possible forecast of strong earthquakes . in this study we use aster / terra multispectral satellite images for detection and analysis of changes in the system of lineaments previous to a strong earthquake . a lineament is a straight or a somewhat curved feature in an image , which it is possible to detect by a special processing of images based on directional filtering and or hough transform . `` the lineament extraction and stripes statistic analysis '' ( lessa ) software package , developed by zlatopolsky ( 1992 , 1997 ) . we assume that the lineaments allow to detect , at least partially , the presence ruptures in the earths crust , and therefore enable one to follow the changes in the system of faults and fractures associated with strong earthquakes . we analysed 6 earthquakes occurred in the pacific coast of the south america and one earthquake in tibet , xizang , china with the richter scale magnitude @xmath0 mw . they were located in the regions with small seasonal variations and limited vegetation to facilitate the tracking of features associated with the seismic activity only . it was found that the number and orientation of lineaments changed significantly about one month before an earthquake approximately , after that the system gradually returns its initial state . this effect increases with the earthquake magnitude , and it is much more easily detectable in case of convergent plate boundaries ( for example , nazca and south american plates ) . the results obtained open a possibility to develop a methodology able to evaluate the seismic risk in the regions with similar geological conditions .
| 294
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0809.3717
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using recent results obtained within the hidden gauge formalism for vector mesons , in which the @xmath0 and @xmath1 resonances are dynamically generated resonances from the @xmath2 interaction , we evaluate the radiative decay of these resonances into @xmath3 . we obtain results for the width in good agreement with the experimental data for the @xmath1 state and a width about a factor two smaller for the @xmath0 resonance , which is also in agreement with the data of the crystal ball collaboration and with the more recent ones from the belle collaboration , which however have a very large uncertainty .
| 102
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1210.0308
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cosmic microwave background ( cmb ) polarization b - modes induced by faraday rotation ( fr ) can provide a distinctive signature of primordial magnetic fields because of their characteristic frequency dependence and because they are only weakly damped on small scales . fr also leads to mode - coupling correlations between the e and b type polarization , and between the temperature and the b - mode . these additional correlations can further help distinguish magnetic fields from other sources of b - modes . we review the fr induced cmb signatures and present the constraints on primordial magnetism that can be expected from upcoming cmb experiments . our results suggest that fr of cmb will be a promising probe of primordial magnetic fields .
| 126
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0809.3555
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the electronic interlayer transport of the lightly doped antiferromagnet @xmath0 has been studied by means of magneto - resistance measurements . the central problem addressed concerns the differences between the electronic interlayer coupling in the tetragonal low - temperature ( ltt ) phase and the orthorhombic low - temperature ( lto ) phase . the key observation is that the spin - flip induced drop in the @xmath1-axis magneto - resistance of the lto phase , which is characteristic for pure @xmath2 , dramatically decreases in the ltt phase . the results show that the transition from orthorhombic to tetragonal symmetry and from collinear to non - collinear antiferromagnetic spin structure eliminates the strain dependent anisotropic interlayer hopping as well as the concomitant spin - valve type transport channel . implications for the stripe ordered ltt phase of @xmath3 are briefly discussed .
| 143
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1406.4702
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we suggest a possible approach to proving the mzard - parisi formula for the free energy in the diluted spin glass models , such as diluted @xmath0-spin or random @xmath0-sat model at any positive temperature . in the main contribution of the paper , we show that a certain small modification of the hamiltonian in any of these models forces all finite - rsb asymptotic gibbs measures in the sense of the overlaps to satisfy the mzard - parisi ansatz for the distribution of spins . unfortunately , what is still missing is a description of the general full - rsb asymptotic gibbs measures . if one could show that the general case can be approximated by finite - rsb case in the right sense then one could a posteriori remove the small modification of the hamiltonian to recover the mzard - parisi formula for the original model . key words : spin glasses , diluted models + mathematics subject classification ( 2010 ) : 60k35 , 60g09 , 82b44
| 170
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0911.0891
|
spiral galaxies have most of their stellar mass in a large rotating disk , and only a modest fraction in a central spheroidal bulge . this challenges present models of galaxy formation : galaxies form at the centre of dark matter halos through a combination of hierarchical merging and gas accretion along cold streams . cosmological simulations thus predict galaxies to rapidly grow their bulge through mergers and instabilities , and to end - up with most of their mass in the bulge and an angular momentum much below the observed level , except in dwarf galaxies . we propose that the continuous return of gas by stellar populations over cosmic times could help to solve this issue . a population of stars formed at a given instant typically returns half of its initial mass in the form of gas over 10 billion years , and the process is not dominated by supernovae explosions but by the long - term mass - loss from low- and intermediate - mass stars . using simulations of galaxy formation , we show that this gas recycling can strongly affect the structural evolution of massive galaxies , potentially solving the bulge fraction issue , as the bulge - to - disk ratio of a massive galaxy can be divided by a factor of 3 . the continuous recycling of baryons through star formation and stellar mass loss helps the growth of disks and their survival to interactions and mergers . instead of forming only early - type , spheroid - dominated galaxies ( s0 and ellipticals ) , the standard cosmological model can successfully account for massive late - type , disk - dominated spiral galaxies ( sb - sc ) .
| 288
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0911.3811
|
with just two @xmath0-parity violating couplings , @xmath1 and @xmath2 , we correlate several channels , namely , @xmath3 ( @xmath4 ) , @xmath5 , and some lepton flavor violating @xmath6 decays . for @xmath7 and for a common superpartner mass of 300 gev , which explain the recently observed excesses in the above @xmath8 decay channels , we predict the following @xmath0-parity violating contributions : @xmath9 , @xmath10 , @xmath11 , and @xmath12 . we exhibit our results through observable versus observable correlation plots . ` pacs nos : 12.60.jv , 13.35.dx ` + ` key words : r - parity violation , lepton flavor violation ` sinp / tnp/2009/25 * correlated enhancements in @xmath13 , @xmath14 of muon , and lepton flavor violating @xmath6 decays with two @xmath0-parity violating couplings * + gautam bhattacharyya @xmath15 , kalyan brata chatterjee @xmath16 , and soumitra nandi @xmath17 + +
| 149
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1205.1414
|
the relatively small binding energy in nuclei suggests that they may be well represented by near - bps skyrmions since their mass is roughly proportional to the baryon number @xmath0 for that purpose , we propose a generalization of the skyrme model with terms up to order six in derivatives of the pion fields and treat the nonlinear @xmath1 and skyrme terms as small perturbations . for our special choice of mass term ( or potential ) @xmath2 , we obtain well - behaved analytical bps - type solutions with nonshell configurations for the baryon density , as opposed to the more complex shell - like configurations found in most extensions of the skyrme model . along with static and ( iso)rotational energies , we add to the mass of the nuclei the often neglected coulomb energy and isospin breaking term . fitting the four model parameters , we find a remarkable agreement for the binding energy per nucleon @xmath3 with respect to experimental data . these results support the idea that nuclei could be near - bps skyrmions . nomdufichiernotesarticle = pubnotes2012prd1v3.tex
| 183
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1609.09350
|
we study systems of three bosons bound by a long - range interaction supplemented by a short - range potential of variable strength . this generalizes the usual two - body exotic atoms where the coulomb interaction is modified by nuclear forces at short distances . the energy shift due to the short - range part of the interaction combines two - body terms similar to the ones entering the trueman - deser formula , and three - body contributions . a phenomenon of level rearrangement is observed , similar to the zeldovich effect , by the onset of an additional stable level which is eventually absorbed by the two - body threshold energy , and can be interpreted as an efimov - like state of the short - range potential .
| 132
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1507.04916
|
this work presents a direct measurement of the @xmath0ru(@xmath1)@xmath2rh cross section via a novel technique using a storage ring , which opens opportunities for reaction measurements on unstable nuclei . a proof - of - principle experiment was performed at the storage ring esr at gsi in darmstadt , where circulating @xmath0ru ions interacted repeatedly with a hydrogen target . the @xmath0ru(@xmath1)@xmath2rh cross section between 9 and 11 mev has been determined using two independent normalization methods . as key ingredients in hauser - feshbach calculations , the @xmath3-ray strength function as well as the level density model can be pinned down with the measured ( @xmath1 ) cross section . furthermore , the proton optical potential can be optimized after the uncertainties from the @xmath3-ray strength function and the level density have been removed . as a result , a constrained @xmath0ru(@xmath1)@xmath2rh reaction rate over a wide temperature range is recommended for @xmath4-process network calculations .
| 157
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0710.3181
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we report new shell - model calculations of the isospin - symmetry - breaking correction , @xmath0 , to superallowed @xmath1 nuclear @xmath2 decay . the most important improvement is the inclusion of core orbitals , which are demonstrated to have a significant impact on the mismatch in the radial wave functions of the parent and daughter states . we determine which core orbitals are important to include from an examination of measured spectroscopic factors in single - nucleon pick - up reactions . in addition , where new sets of effective interactions have become available since our last calculation , we now include them ; this leads to small changes in @xmath3 as well . we also examine the new radiative - correction calculation by marciano and sirlin and , by a simple reorganization , show that it is possible to preserve the conventional separation into a nucleus - independent inner " radiative term , @xmath4 , and a nucleus - dependent outer " term , @xmath5 we tabulate the new values for @xmath0 , @xmath3 and @xmath5 for twenty superallowed transitions , including the thirteen currently well - studied cases . with these new correction terms the corrected @xmath6 values for the thirteen cases are statistically consistent with one another and the anomalousness of the @xmath7v result disappears . these new calculations lead to a lower average @xmath8 value and a higher value for @xmath9 . the sum of squares of the top - row elements of the ckm matrix now agrees exactly with unitarity .
| 258
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0903.3275
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a graphene quantum dot under intense ac field and static low magnetic field is investigated . from a tight - binding perspective , applying a fourier - floquet transformation and renormalization process , we observe that graphene -intrinsically anisotropic- reveals field polarization signatures in the quasi - density of states . for the ac field polarized along the armchair direction , the dressed electronic structure shows an emergent property : an ac field induced quantum ring . this is inferred by the orientation - dependent formation of a miniband of energy states periodically modulated with increasing magnetic field , exactly analogous to the behavior of a quantum ring spectrum .
| 110
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1211.5289
|
we study the effect of a magnetic field in the kondo regime of a double - quantum - dot system consisting of a strongly correlated dot ( the `` side dot '' ) coupled to a second , noninteracting dot that also connects two external leads . we show , using the numerical renormalization group , that application of an in - plane magnetic field sets up a subtle interplay between electronic interference , kondo physics , and zeeman splitting with nontrivial consequences for spectral and transport properties . the value of the side - dot spectral function at the fermi level exhibits a nonuniversal field dependence that can be understood using a form of the friedel sum rule that appropriately accounts for the presence of an energy- and spin - dependent hybridization function . the applied field also accentuates the exchange - mediated interdot coupling , which dominates the ground state at intermediate fields leading to the formation of antiparallel magnetic moments on the dots . by tuning gate voltages and the magnetic field , one can achieve complete spin polarization of the linear conductance between the leads , raising the prospect of applications of the device as a highly tunable spin filter . the system s low - energy properties are qualitatively unchanged by the presence of weak on - site coulomb repulsion within the second dot .
| 230
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1601.05165
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we propose a method to realize diluted magnetic semiconductors ( dmss ) with p- and n - type carriers by choosing host semiconductors with a narrow band gap . by employing a combination of the density function theory and quantum monte carlo simulation , we demonstrate such semiconductors using mn - doped bazn@xmath0as@xmath0 , which has a band gap of 0.2 ev . in addition , we found a nontoxic dms mn - doped bazn@xmath0sb@xmath0 , of which the curie temperature t@xmath1 is predicted to be higher than that of mn - doped bazn@xmath0as@xmath0 , the t@xmath1 of which was up to 230 k in a recent experiment .
| 109
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cond-mat0101187
|
two - dimensional ( 2d ) @xmath0 model subject to three different types of dynamics , namely monte carlo , resistivity shunted junction ( rsj ) , and relaxational dynamics , is numerically simulated . from the comparisons of the current - voltage ( @xmath1-@xmath2 ) characteristics , it is found that up to some constants @xmath1-@xmath2 curves at a given temperature are identical to each other in a broad range of external currents . simulations of the villain model and the modified 2d @xmath0 model allowing stronger thermal vortex fluctuations are also performed with rsj type of dynamics . the finite - size scaling suggested in medvedyeva _ et al . _ [ phys . rev . b ( in press ) ] is confirmed for all dynamic models used , implying that this finite - size scaling behaviors in the vicinity of the kosterlitz - thouless transition are quite robust . 2
| 154
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quant-ph0404145
|
a constraint on two complementary knowledge excesses by maximal violation of bell inequalities for a single copy of any mixed state of two qubits @xmath0 is analyzed . the complementary knowledge excesses @xmath1 and @xmath2 quantify an enhancement of ability to predict results of the complementary projective measurements @xmath3 on the qubit @xmath4 from the projective measurements @xmath5 performed on the qubit @xmath6 . for any state @xmath7 and for arbitrary @xmath3 and @xmath5 , the knowledge excesses satisfy the following inequality @xmath8 , where @xmath9 is maximum of violation of bell inequalities under single - copy local operations ( local filtering and unitary transformations ) . particularly , for the bell - diagonal states only an appropriate choice of the measurements @xmath3 and @xmath5 are sufficient to saturate the inequality .
| 132
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cond-mat0109128
|
we analyze the long range ising spin glass in a transverse field @xmath0 by using grassmann variables in a field theory where the spin operators are represented by bilinear combinations of fermionic fields . we compare the results of two fermionic models . in the four state ( 4s)-model the diagonal @xmath1 operator has two vanishing eigenvalues , that are suppressed by a restraint in the two states ( 2s)-model . within a replica symmetric theory and in the static approximation we obtain similar results for both models . they both exhibit a critical temperature @xmath2 that decreases when @xmath0 increases , until it reaches a quantum critical point ( qcp ) at the same value of @xmath3 and they are both unstable under replica symmetry breaking in the whole spin glass phase .
| 134
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hep-th9508015
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the large-@xmath0 saddle - point equations for the principal chiral models defined on a @xmath1 dimensional simplex are derived from the external field problem for unitary integrals . the saddle point equation are studied analytically and numerically in many relevant instances , including @xmath2 and @xmath3 , with special attention to the critical domain , which is found to correspond to @xmath4 for all @xmath5 . related models ( chiral chains ) are discussed and large-@xmath0 solutions are analyzed . # 1currentlabel@secnum>0 .[#1 ] critical behavior of simplicial chiral models @xmath6 physics department , boston university , boston , ma 02215 , usa . + @xmath7 dipartimento di fisica delluniversit and i.n.f.n . , i-56126 pisa , italy . + @xmath8 department of physics , brown university , providence ri 02912 , usa
| 133
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1609.09862
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we present the design and implementation of an @xmath0-stable spectral method for the discretization of the vlasov - poisson model of a collisionless plasma in one space and velocity dimension . the velocity and space dependence of the vlasov equation are resolved through a truncated spectral expansion based on legendre and fourier basis functions , respectively . the poisson equation , which is coupled to the vlasov equation , is also resolved through a fourier expansion . the resulting system of ordinary differential equation is discretized by the implicit second - order accurate crank - nicolson time discretization . the non - linear dependence between the vlasov and poisson equations is iteratively solved at any time cycle by a jacobian - free newton - krylov method . in this work we analyze the structure of the main conservation laws of the resulting legendre - fourier model , e.g. , mass , momentum , and energy , and prove that they are exactly satisfied in the semi - discrete and discrete setting . the @xmath0-stability of the method is ensured by discretizing the boundary conditions of the distribution function at the boundaries of the velocity domain by a suitable penalty term . the impact of the penalty term on the conservation properties is investigated theoretically and numerically . an implementation of the penalty term that does not affect the conservation of mass , momentum and energy , is also proposed and studied . a collisional term is introduced in the discrete model to control the filamentation effect , but does not affect the conservation properties of the system . numerical results on a set of standard test problems illustrate the performance of the method . vlasov - poisson , legendre - fourier discretization , conservation laws stability
| 296
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1012.3526
|
for chaotic cavities with scattering leads attached , transport properties can be approximated in terms of the classical trajectories which enter and exit the system . with a semiclassical treatment involving fine correlations between such trajectories we develop a diagrammatic technique to calculate the moments of various transport quantities . namely , we find the moments of the transmission and reflection eigenvalues for systems with and without time reversal symmetry . we also derive related quantities involving an energy dependence : the moments of the wigner delay times and the density of states of chaotic andreev billiards , where we find that the gap in the density persists when subleading corrections are included . finally , we show how to adapt our techniques to non - linear statistics by calculating the correlation between transport moments . in each setting , the answer for the @xmath0-th moment is obtained for arbitrary @xmath0 ( in the form of a moment generating function ) and for up to the three leading orders in terms of the inverse channel number . our results suggest patterns which should hold for further corrections and by matching with the low order moments available from random matrix theory we derive likely higher order generating functions .
| 208
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1702.07833
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arbitrary rotation of a qubit can be performed with a three - pulse sequence ; for example , zyz rotations . however , this requires precise control of the relative phase and timing between the pulses , making it technically challenging in optical implementation in a short time scale . here we show any zyz rotations can be implemented with a single laser - pulse , that is _ a chirped pulse with a temporal hole_. the hole of this shaped pulse induces a non - adiabatic interaction in the middle of the adiabatic evolution of the chirped pulse , converting the central part of an otherwise simple z - rotation to a y rotation , constructing zyz rotations . the result of our experiment performed with shaped femtosecond laser pulses and cold rubidium atoms shows strong agreement with the theory .
| 142
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1410.1826
|
an @xmath0 matrix @xmath1 with column supports @xmath2 is @xmath3-separable if the disjunctions @xmath4 are all distinct over all sets @xmath5 of cardinality @xmath3 . while a simple counting bound shows that @xmath6 rows are required for a separable matrix to exist , in fact it is necessary for @xmath7 to be about a factor of @xmath3 more than this . in this paper , we consider a weaker definition of ` almost @xmath3-separability ' , which requires that the disjunctions are ` mostly distinct ' . we show using a random construction that these matrices exist with @xmath8 rows , which is optimal for @xmath9 . further , by calculating explicit constants , we show how almost separable matrices give new bounds on the rate of nonadaptive group testing .
| 131
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1211.3153
|
since the smallest leptonic mixing angle @xmath0 has been measured to be relatively large , it is quite promising to constrain or determine the leptonic dirac cp - violating phase @xmath1 in future neutrino oscillation experiments . given some typical values of @xmath2 , @xmath3 , and @xmath4 at the low - energy scale , as well as current experimental results of the other neutrino parameters , we perform a systematic study of the radiative corrections to @xmath1 by using the one - loop renormalization group equations in the minimal supersymmetric standard model and the universal extra - dimensional model . it turns out that @xmath1 is rather stable against radiative corrections in both models , except for the minimal supersymmetric standard model with a very large value of @xmath5 . both cases of majorana and dirac neutrinos are discussed . in addition , we use the preliminary indication of @xmath6 or @xmath7 from the latest global - fit analyses of data from neutrino oscillation experiments to illustrate how it will be modified by radiative corrections .
| 177
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1603.08401
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in the present work pll - based circuits with sinusoidal phase detector characteristic and active proportionally - integrating ( pi ) filter are considered . the notion of lock - in range an important characteristic of pll - based circuits , which corresponds to the synchronization without cycle slipping , is studied . for the lock - in range a rigorous mathematical definition is discussed . numerical and analytical estimates for the lock - in range are obtained . phase - locked loop , nonlinear analysis , pll , two - phase pll , lock - in range , gardner s problem on unique lock - in frequency , pull - out frequency
| 113
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1307.0784
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we define a markov process in a forward population model with backward genealogy given by the @xmath0-coalescent . this markov process , called the fixation line , is related to the block counting process through its hitting times . two applications are discussed . the probability that the @xmath1-coalescent is deeper than the ( @xmath2-@xmath3)-coalescent is studied . the distribution of the number of blocks in the last coalescence of @xmath1-beta(@xmath4)-coalescents is proved to converge as @xmath5 , and the generating function of the limiting random variable is computed . the probability for an integer to be in the range of the block counting process of @xmath1-beta(@xmath4)-coalescents is also given in the limit @xmath5 .
| 115
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1202.1001
|
we consider two reflecting diffusion processes @xmath0 with a moving reflection boundary given by a non - decreasing pure jump markov process @xmath1 . between the jumps of the reflection boundary the diffusion part behaves as a reflecting brownian motion with negative drift or as a reflecting ornstein - uhlenbeck process . in both cases at rate @xmath2 for some @xmath3 the reflection boundary jumps to a new value chosen uniformly in @xmath4 $ ] . since after each jump of the reflection boundary the diffusions are reflected at a higher level we call the processes _ brownian ratchet _ and _ ornstein - uhlenbeck ratchet_. such diffusion ratchets are biologically motivated by passive protein transport across membranes . the processes considered here are generalisations of the brownian ratchet ( without drift ) studied in @xcite . for both processes we prove a law of large numbers , in particular each of the ratchets moves to infinity at a positive speed which can be computed explicitly , and a central limit theorem .
| 173
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1406.5857
|
the interferometric power of a bipartite quantum state quantifies the precision , measured by quantum fisher information , that such a state enables for the estimation of a parameter embedded in a unitary dynamics applied to one subsystem only , in the worst - case scenario where a full knowledge of the generator of the dynamics is not available _ a priori_. for finite - dimensional systems , this quantity was proven to be a faithful measure of quantum correlations beyond entanglement . here we extend the notion of interferometric power to the technologically relevant setting of optical interferometry with continuous - variable probes . by restricting to gaussian local dynamics , we obtain a closed formula for the interferometric power of all two - mode gaussian states . we identify separable and entangled gaussian states which maximize the interferometric power at fixed mean photon number of the probes , and discuss the associated metrological scaling . at fixed entanglement of the probes , highly thermalized states can guarantee considerably larger precision than pure two - mode squeezed states .
| 180
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astro-ph0504486
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the equivalence of mass and energy is indelibly linked with relativity , both by scientists and in the popular mind . here i prove that @xmath0 by demanding momentum conservation of an object that emits two equal electromagnetic wave packets in opposite directions in its own frame . in contrast to einstein s derivation of this equation , which applies energy conservation to a similar thought experiment , the new derivation employs no effects that are greater than first order in @xmath1 and therefore does not rely on results from special relativity . in addition to momentum conservation , it uses only aberration of starlight and the electromagnetic - wave momentum - energy relation @xmath2 , both of which were established by 1884 . in particular , no assumption is made about the constancy of the speed of light , and the derivation proceeds equally well if one assumes that light is governed by a galilean transformation . in view of this , it is somewhat puzzling that the equivalence of mass and energy was not derived well before the advent of special relativity . the new derivation is simpler and more transparent than einstein s and is therefore pedagogically useful .
| 202
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astro-ph9403039
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in this paper we show that the conventional diffusive shock acceleration mechanism for cosmic rays associated with relativistic astrophysical shocks in active galactic nuclei ( agns ) has severe difficulties to explain the highest energy cosmic ray events . we show that protons above around @xmath0 could have marginally been produced by this mechanism in an agn or a rich galaxy cluster not further away than around @xmath1 . however , for the highest energy fly s eye and yakutsk events this is inconsistent with the observed arrival directions . galactic and intergalactic magnetic fields appear unable to alter the direction of such energetic particles by more than a few degrees . we also discuss some other options for these events associated with relativistic particles including pulsar acceleration of high @xmath2 nuclei . at the present stage of knowledge the concept of topological defects left over from the early universe as the source for such events appears to be a promising option . such sources are discussed and possible tests of this hypothesis are proposed . 2gcm^-2 # 1#23.6pt 6.5 in 8.5 in -0.25 in + g. sigl@xmath3 , d. n. schramm@xmath3 and p. bhattacharjee@xmath4 + _ @xmath5department of astronomy & astrophysics + enrico fermi institute , the university of chicago , chicago , il 60637 - 1433 _ + _ @xmath6nasa / fermilab astrophysics center + fermi national accelerator laboratory , batavia , il 60510 - 0500 _ + _ @xmath4indian institute of astrophysics + sarjapur road , koramangala , bangalore 560 034 , india _
| 257
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quant-ph0010022
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by using finite resolution measurements it is possible to simultaneously obtain noisy information on two non - commuting polarization components of a single photon . this method can be applied to a pair of entangled photons with polarization statistics that violate bell s inequalities . the theoretically predicted results show that the non - classical nature of entanglement arises from negative joint probabilities for the non - commuting polarization components . these negative probabilities allow a `` disentanglement '' of the statistics , providing new insights into the non - classical properties of quantum information . + keywords : bell s inequalities , photon statistics , entanglement
| 107
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1507.07626
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we theoretically investigate magnetic properties of a unitary fermi gas in a harmonic trap . including strong pairing fluctuations within the framework of an extended @xmath0-matrix approximation ( etma ) , as well as effects of a trap potential within the local density approximation ( lda ) , we calculate the local spin susceptibility @xmath1 above the superfluid phase transition temperature @xmath2 . we show that the formation of preformed singlet cooper pairs anomalously suppresses @xmath1 in the trap center near @xmath2 . we also point out that , in the unitarity limit , the spin - gap temperature in a uniform fermi gas can be evaluated from the observation of the spatial variation of @xmath1 . since a real ultracold fermi gas is always in a trap potential , our results would be useful for the study of how this spatial inhomogeneity affects thermodynamic properties of an ultracold fermi gas in the bcs - bec crossover region . pacs numbers : 03.75.hh , 05.30.fk , 67.85.lm .
| 168
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1110.0984
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we report first - principles calculations of the phonon dispersion spectrum , thermal expansion , and heat capacity of uranium dioxide . the so - called direct method , based on the quasiharmonic approximation , is used to calculate the phonon frequencies within a density functional framework for the electronic structure . the phonon dispersions calculated at the theoretical equilibrium volume agree well with experimental dispersions . the computed phonon density of states ( dos ) compare reasonably well with measurement data , as do also the calculated frequencies of the raman and infrared active modes including the lo / to splitting . to study the pressure dependence of the phonon frequencies we calculate phonon dispersions for several lattice constants . our computed phonon spectra demonstrate the opening of a gap between the optical and acoustic modes induced by pressure . taking into account the phonon contribution to the total free energy of uo@xmath0 its thermal expansion coefficient and heat capacity have been _ ab initio _ computed . both quantities are in good agreement with available experimental data for temperatures up to about 500k .
| 186
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quant-ph0603012
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suppose we have an @xmath0-qubit system , and we are given a collection of local density matrices @xmath1 , where each @xmath2 describes some subset of the qubits . we say that @xmath1 are `` consistent '' if there exists a global state @xmath3 ( on all @xmath0 qubits ) whose reduced density matrices match @xmath1 . we prove the following result : if @xmath1 are consistent with some state @xmath4 , then they are also consistent with a state @xmath5 of the form @xmath6 , where each @xmath7 is a hermitian matrix acting on the same qubits as @xmath2 , and @xmath8 is a normalizing factor . ( this is known as a gibbs state . ) actually , we show a more general result , on the consistency of a set of expectation values @xmath9 , where the observables @xmath10 need not commute . this result was previously proved by jaynes ( 1957 ) in the context of the maximum - entropy principle ; here we provide a somewhat different proof , using properties of the partition function .
| 181
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1311.5747
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we propose the 14-band @xmath0 model to calculate spin - orbit splittings of the valence subbands in semiconductor quantum wells . the reduced symmetry of quantum well interfaces is incorporated by means of additional terms in the boundary conditions which mix the @xmath1 conduction and valence bloch functions at the interfaces . it is demonstrated that the interface - induced effect makes the dominating contribution to the heavy - hole spin splitting . a simple analytical expression for the interface contribution is derived . in contrast to the 4@xmath24 effective hamiltonian model , where the problem of treating the @xmath3 term seems to be unsolvable , the 14-band model naturally avoids and overcomes this problem . our results are in agreement with the recent atomistic calculations [ j .- w . luo et al . , phys . rev . lett . * 104 * , 066405 ( 2010 ) ] .
| 152
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1505.03807
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we examine the behavior of quantum correlations of spin pairs in a finite anisotropic @xmath0 spin chain immersed in a transverse magnetic field , through the analysis of the quantum discord and the conventional and quadratic one way - information deficits . we first provide a brief review of these measures , showing that the last ones can be obtained as particular cases of a generalized information deficit based on general entropic forms . all these measures coincide with an entanglement entropy in the case of pure states , but can be non - zero in separable mixed states , vanishing just for classically correlated states . it is then shown that their behavior in the exact ground state of the chain exhibits similar features , deviating significantly from that of the pair entanglement below the critical field . in contrast with entanglement , they reach full range in this region , becoming independent of the pair separation and coupling range in the immediate vicinity of the factorizing field . it is also shown , however , that significant differences between the quantum discord and the information deficits arise in the local minimizing measurement that defines them . both analytical and numerical results are provided .
| 206
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0704.0426
|
during the epoch of reionization , the formation of radiation sources is accompanied by the growth of a @xmath0 photodissociating flux . we estimate the impact of this flux on the formation of molecular hydrogen and cooling in the first galaxies , assuming different types of radiation sources ( e.g. pop ii and pop iii stars , miniquasars ) . we find that @xmath0 photodissociation reduces the formation of @xmath1 molecules by a factor of @xmath2 , where @xmath3 is the mean ionized fraction in the igm , @xmath4 is the fraction of ionizing photons that escape from their progenitor halos , @xmath5 is the local gas overdensity and @xmath6 is an order unity constant which depends on the type of radiation source . by the time a significant fraction of the universe becomes ionized , @xmath0 photodissociation may significantly reduce the @xmath1 abundance and , with it , the primordial star formation rate , delaying the progress of reionization .
| 161
|
1609.02602
|
we model the mass accretion rate @xmath0 to stellar mass @xmath1 correlation that has been inferred from observations of intermediate to upper mass t tauri stars that is @xmath2 . we explain this correlation within the framework of quiescent disk evolution , in which accretion is driven largely by gravitational torques acting in the bulk of the mass and volume of the disk . stresses within the disk arise from the action of gravitationally driven torques parameterized in our 1d model in terms of toomre s @xmath3 criterion . we do not model the hot inner sub - au scale region of the disk that is likely stable according to this criterion , and appeal to other mechanisms to remove or redistribute angular momentum and allow accretion onto the star . our model has the advantage of agreeing with large - scale angle - averaged values from more complex nonaxisymmetric calculations . the model disk transitions from an early phase ( dominated by initial conditions inherited from the burst mode of accretion ) into a later self - similar mode characterized by a steeper temporal decline in @xmath0 . the models effectively reproduce the spread in mass accretion rates that have been observed for protostellar objects of @xmath4 , such as those found in the @xmath5 ophiuchus and taurus star forming regions . we then compare realistically sampled populations of young stellar objects produced by our model to their observational counterparts . we find these populations to be statistically coincident , which we argue is evidence for the role of gravitational torques in the late time evolution of quiescent protostellar disks . & accretion ; accretion disks ; hydrodynamics ; stars : formation ; stars : protostellar disks
| 288
|
1610.05722
|
we consider @xmath0 , a solution of @xmath1 which blows up at some time @xmath2 , where @xmath3 , @xmath4 and @xmath5 . define @xmath6 to be the blow - up set of @xmath7 , that is the set of all blow - up points . under suitable nondegeneracy conditions , we show that if @xmath8 contains a @xmath9-dimensional continuum for some @xmath10 , then @xmath8 is in fact a @xmath11 manifold . the crucial step is to derive a refined asymptotic behavior of @xmath7 near blow - up . in order to obtain such a refined behavior , we have to abandon the explicit profile function as a first order approximation and take a non - explicit function as a first order description of the singular behavior . this way we escape logarithmic scales of the variable @xmath12 and reach significant small terms in the polynomial order @xmath13 for some @xmath14 . the refined asymptotic behavior yields geometric constraints of the blow - up set , leading to more regularity on @xmath8 . tej - eddine ghoul@xmath15 , van tien nguyen@xmath15 and hatem zaag@xmath16
| 185
|
1411.7633
|
we study the ground state quantum fragmentation in a mixture of a polar condensate and a ferromagnetic condensate when subject to an external magnetic field . we pay more attentions to the polar condensate and find that it will be less fragile in the mixture when perturbed by the magnetic field . both atom numbers and the number fluctuations in the spin-0 component will keep in a high magnitude of order of @xmath0 when the magnetization of the system is increased . the role of the ferromagnetic condensate is to provide a uniform and stable background which can delay the rapid shrink of the 0-component population and make it possible to capture the super - fragmentation . our method has potential applications in measuring the inter - species spin - coupling interaction through adjusting the magnetic field .
| 138
|
0711.3049
|
let @xmath0 be an undirected graph on @xmath1 vertices and let @xmath2 be the set of all real symmetric @xmath3 matrices whose nonzero off - diagonal entries occur in exactly the positions corresponding to the edges of @xmath0 . the inverse inertia problem for @xmath0 asks which inertias can be attained by a matrix in @xmath2 . we give a complete answer to this question for trees in terms of a new family of graph parameters , the maximal disconnection numbers of a graph . we also give a formula for the inertia set of a graph with a cut vertex in terms of inertia sets of proper subgraphs . finally , we give an example of a graph that is not inertia - balanced , and investigate restrictions on the inertia set of any graph . _ keywords : _ combinatorial matrix theory , graph , hermitian , inertia , minimum rank , symmetric , tree _ ams classification : _ 05c05 ; 05c50 ; 15a03 ; 15a57
| 169
|
0812.0124
|
high - energy emission from gamma - ray bursts ( grbs ) is widely expected but had been sparsely observed until recently when the _ fermi _ satellite was launched . if @xmath0 tev gamma rays are produced in grbs and can escape from the emission region , they are attenuated by the cosmic infrared background photons , leading to regeneration of @xmath1 gev - tev secondary photons via inverse - compton scattering . this secondary emission can last for a longer time than the duration of grbs , and it is called a pair echo . we investigate how this pair echo emission affects spectra and light curves of high energy afterglows , considering not only prompt emission but also afterglow as the primary emission . detection of pair echoes is possible as long as the intergalactic magnetic field ( igmf ) in voids is weak . we find ( 1 ) that the pair echo from the primary afterglow emission can affect the observed high - energy emission in the afterglow phase after the jet break , and ( 2 ) that the pair echo from the primary prompt emission can also be relevant , but only when significant energy is emitted in the tev range , typically @xmath2 . even non - detections of the pair echoes could place interesting constraints on the strength of igmf . the more favorable targets to detect pair echoes may be the naked " grbs without conventional afterglow emission , although energetic naked grbs would be rare . if the igmf is weak enough , it is predicted that the gev emission extends to @xmath3 s. [ firstpage ] gamma rays : bursts magnetic fields radiation mechanisms : nonthermal
| 288
|
0910.4889
|
nancy g. kinnersley and michael a. langston has determined the excluded minors for the class of graphs with path - width at most two by computer . their list consisted of 110 graphs . such a long list is difficult to handle and gives no insight to structural properties . we take a different route , and concentrate on the building blocks and how they are glued together . in this way , we get a characterization of @xmath0-connected and @xmath0-edge - connected graphs with path - width at most two . along similar lines , we sketch the complete characterization of graphs with path - width at most two .
| 111
|
hep-ph0403146
|
i study the very recently discovered s=-2 resonance @xmath0 ( 1886 ) by the na49 collaboration at the cern sps . this resonance was already predicted , with a mass close to 1.9 gev , in a recent publication mostly dedicated to the s=1 resonance @xmath1(1540 ) . to confirm this recent prediction , i apply the same standard quark model with a quark - antiquark annihilation constrained by chiral symmetry . this method also explained with success the repulsive hard core of nucleon - nucleon , kaon - nucleon exotic scattering , and the short range attraction present in pion - nucleon and pion - pion non - exotic scattering . i find that repulsion excludes the @xmath0 as a @xmath2 s - wave pentaquark . i explore the @xmath0 as a heptaquark , equivalent to a @xmath3 linear molecule , with positive parity and total isospin @xmath4 . i find that the kaon - kaon repulsion is cancelled by the attraction existing in the kaon - nucleon channels . in our framework this state is easier to bind than the @xmath1 described by a @xmath5 borromean bound - state . the remaining @xmath6 doublet and @xmath7 triplet of the exotic anti - decuplet are also studied , and the coupling to p - wave decay channels is briefly addressed .
| 222
|
1609.00370
|
in this paper we analyze the quantum phase estimation problem using continuous - variable , entangled squeezed coherent states ( quasi - bell states ) . we calculate the quantum fisher information having the quasi - bell states as probe states and find that both squeezing and entanglement might bring advantages , increasing the precision of the phase estimation compared to protocols which employ other continuous variable states , e.g. , coherent or non - entangled states . we also study the influence of a linear ( unitary ) perturbation during the phase estimation process , and conclude that entanglement is a useful resource in this case as well . * quantum phase estimation with squeezed quasi - bell states * douglas delgado de souza and a. vidiella - barranco + +
| 132
|
astro-ph0408502
|
to date , the only low surface brightness ( lsb ) galaxies which have been detected in co are the massive lsb ( mlsb ) galaxies . in 2003 , oneil , schinnerer , & hofner hypothesized that is the prominent bulge component in mlsb galaxies , not present in less massive low surface brightness galaxies , which gives rise to the detectable quantities of co gas . to test this hypothesis , we have used the iram 30 m telescope to obtain three new , deep co j(1@xmath00 ) and j(2@xmath01 ) observations of mlsb galaxies . two of the three galaxies observed were detected in co one in the j(1@xmath00 ) line and the other in both the j(1@xmath00 ) and j(2@xmath01 ) lines , bringing the total number of mlsb galaxies with co detections to 5 , out of a total of 9 mlsb galaxies observed at co to date . the third object had no detection to 2 mk at co j(1@xmath00 ) . comparing all mlsb galaxy co results with surveys of high surface brightness galaxies , we find the mlsb galaxies m@xmath1 and m@xmath1/m@xmath2 values fall within the ranges typically found for high surface brightness objects , albeit at the low end of the distribution , with the two mlsb galaxies detected at co in this survey having the highest m@xmath1/m@xmath2 values yet measured for any lsb system , by factors of 23 .
| 240
|
1312.3735
|
a task is randomly drawn from a finite set of tasks and is described using a fixed number of bits . all the tasks that share its description must be performed . upper and lower bounds on the minimum @xmath0-th moment of the number of performed tasks are derived . the key is an analog of the kraft inequality for partitions of finite sets . when a sequence of tasks is produced by a source of a given rnyi entropy rate of order @xmath1 and @xmath2 tasks are jointly described using @xmath3 bits , it is shown that for @xmath4 larger than the rnyi entropy rate , the @xmath0-th moment of the ratio of performed tasks to @xmath2 can be driven to one as @xmath2 tends to infinity , and that for @xmath4 less than the rnyi entropy rate it tends to infinity . this generalizes a recent result for iid sources by the same authors . a mismatched version of the direct part is also considered , where the code is designed according to the wrong law . the penalty incurred by the mismatch can be expressed in terms of a divergence measure that was shown by sundaresan to play a similar role in the massey - arikan guessing problem .
| 212
|
nucl-th9802008
|
we calculate the cross sections of the elastic and inelastic breakup modes for the inclusive breakup reaction @xmath0si(@xmath1b,@xmath2be ) at beam energies between 10 - 40 mev / nucleon within a direct fragmentation model formulated in the framework of the post form distorted - wave born - approximation . in contrast to the case of the stable isotopes , the inelastic breakup mode is found to contribute only up to 30@xmath3 to the total breakup cross section , which is in agreement with the recently measured experimental data . however , the high energy tail of the energy spectra of @xmath2be fragment is dominated by the inelastic breakup mode . the breakup amplitude is found to be dominated by contributions from distances well beyond the nuclear surface . keywords : nuclear breakup of @xmath1b on @xmath0si , elastic and inelastic breakup cross sections , proton halo in @xmath1b . pacs no . 25.60.gc , 24.10.-i , 25.70.mn psfig = 24 true pt nuclear breakup of @xmath1b in a direct fragmentation model + * r. shyam@xmath4 and h. lenske@xmath5 * + @xmath4_saha institute of nuclear physics , calcutta - 700 064 , india _ + @xmath5_institut fr theoretische physik , universitt giessen , d-35392 giessen , germany _ +
| 208
|
1211.3605
|
in this paper , we study the ricci flow of solvmanifolds whose lie algebra has an abelian ideal of codimension one , by using the bracket flow . we prove that solutions to the ricci flow are immortal , the @xmath0-limit of bracket flow solutions is a single point , and that for any sequence of times there exists a subsequence in which the ricci flow converges , in the pointed topology , to a manifold which is locally isometric to a flat manifold . we give a functional which is non - increasing along a normalized bracket flow that will allow us to prove that given a sequence of times , one can extract a subsequence converging to an algebraic soliton , and to determine which of these limits are flat . finally , we use these results to prove that if a lie group in this class admits a riemannian metric of negative sectional curvature , then the curvature of any ricci flow solution will become negative in finite time .
| 173
|
cond-mat0005238
|
we calculate the optical conductivity , @xmath0 , in the normal state fullerene superconductors by self - consistently including the impurity scatterings , the electron - phonon and electron - electron coulomb interactions . the finite bandwidth of the fullerenes is explicitely considered , and the vertex corection is included @xmath1 @xmath2 nambu in calculating the renormalized green s function . @xmath0 is obtained by calculating the current - current correlation function with the renormalized green s function in the matsubara frequency and then performing analytic continuation to the real frequency at finite temperature . the drude weight in @xmath0 is strongly suppressed due to the interactions and transfered to the mid - infrared region around and above @xmath3 ev which is somewhat less pronounced and much broader compared with the expermental observation by degiorgi @xmath4 @xmath5 . 2
| 139
|
cond-mat0701755
|
based on the _ ab - initio _ band structure for na@xmath0coo@xmath1 we derive the single - electron energies and the effective tight - binding description for the @xmath2 bands using projection procedure . due to the presence of the next - nearest - neighbor hoppings a local minimum in the electronic dispersion close to the @xmath3 point of the first brillouin zone forms . correspondingly , in addition to a large fermi surface an electron pocket close to the @xmath3 point emerges at high doping concentrations . the latter yields the new scattering channel resulting in a peak structure of the itinerant magnetic susceptibility at small momenta . this indicates dominant itinerant in - plane ferromagnetic fluctuations above certain critical concentration @xmath4 , in agreement with neutron scattering data . below @xmath4 the magnetic susceptibility shows a tendency towards the antiferromagnetic fluctuations . we further analyze the many - body effects on the electronic and magnetic excitations using various approximations applicable for different @xmath5 ratio .
| 167
|
0709.1890
|
let @xmath0 be a collection of smooth rational plane curves . we prove that the addition - deletion operation used in the study of hyperplane arrangements has an extension which works for a large class of arrangements of smooth rational curves , giving an inductive tool for understanding the freeness of the module @xmath1 of logarithmic differential forms with pole along @xmath2 . we also show that the analog of terao s conjecture ( freeness of @xmath1 is combinatorially determined if @xmath2 is a union of lines ) is false in this setting . [ section ] [ defn0]proposition [ defn0]conjecture [ defn0]theorem [ defn0]lemma [ defn0]corollary [ defn0]example
| 109
|
1007.2702
|
the non - potentiality ( np ) of the solar magnetic fields is measured traditionally in terms of magnetic shear angle i.e. , the angle between observed and potential field azimuth . here , we introduce another measure of shear that has not been studied earlier in solar active regions , i.e. the one that is associated with the inclination angle of the magnetic field . this form of shear , which we call as the dip - shear " , can be calculated by taking the difference between the observed and potential field inclination . in this _ letter _ , we study the evolution of dip - shear as well as the conventional twist - shear in a @xmath0-sunspot using high - resolution vector magnetograms from _ hinode _ space mission . we monitor these shears in a penumbral region located close to flare site during 12 and 13 december 2006 . it is found that : ( i ) the penumbral area close to the flaring site shows high value of twist - shear and dip - shear as compared to other parts of penumbra , ( ii ) after the flare the value of dip - shear drops in this region while the twist - shear in this region tends to increase after the flare , ( iii ) the dip - shear and twist - shear are correlated such that pixels with large twist - shear also tend to exhibit large dip - shear , and ( iv ) the correlation between the twist - shear and dip - shear is tighter after the flare . the present study suggests that monitoring twist - shear during the flare alone is not sufficient but we need to monitor it together with dip - shear .
| 299
|
nucl-th0312023
|
considering two - body integral equations we show how they can be dimensionally reduced by integrating exactly over the azimuthal angle of the intermediate momentum . numerical solution of the resulting equation is feasible without employing a partial - wave expansion . we illustrate this procedure for the bethe - salpeter equation for pion - nucleon scattering and give explicit details for the one - nucleon - exchange term in the potential . finally , we show how this method can be applied to pion photoproduction from the nucleon with @xmath0 rescattering being treated so as to maintain unitarity to first order in the electromagnetic coupling . the procedure for removing the azimuthal angle dependence becomes increasingly complex as the spin of the particles involved increases . = 10000
| 129
|
1306.0487
|
the quantum spin-1/2 orthogonal - dimer chain with the heisenberg intra - dimer and ising inter - dimer interactions in a magnetic field is considered by a rigorous approach . the model conserves the @xmath0-component of total spin on vertical heisenberg bonds and this property is used to calculate exactly the partition function using the transfer - matrix method . we have found the ground - state phase diagram of the given model in a magnetic field as well as the macroscopic degeneracy along field - induced transitions accompanied with the magnetization jumps . the model exhibits two intermediate fractional plateaux at one - quarter and one - half of the saturation magnetization . we have examined the effect of the exchange anisotropy in the @xmath1 heisenberg intra - dimer interaction on the ground state . it is shown that the one - quarter and one - half plateaux may disappear from the magnetization curve for the ferromagnetic heisenberg intra - dimer interaction . we have also studied rigorously the effect of frustrated interactions on the thermodynamic and magnetic properties of the model and show how the macroscopic degeneracy of the ground state is reflected in the low - temperature behavior of the magnetization , entropy and specific heat . a possibility of observing enhanced magnetocaloric effect during the adiabatic demagnetization is discussed in detail .
| 226
|
1209.2471
|
an acyclic edge coloring of a graph @xmath0 is a proper edge coloring such that no bichromatic cycles are produced . the acyclic chromatic index @xmath1 of @xmath0 is the smallest integer @xmath2 such that @xmath0 has an acyclic edge coloring using @xmath2 colors . fiam@xmath3ik ( 1978 ) and later alon , sudakov and zaks ( 2001 ) conjectured that @xmath4 for any simple graph @xmath0 with maximum degree @xmath5 . basavaraju and chandran ( 2009 ) showed that every graph @xmath0 with @xmath6 , which is not 4-regular , satisfies the conjecture . in this paper , we settle the 4-regular case , i.e. , we show that every 4-regular graph @xmath0 has @xmath7 . * keywords : * acyclic edge coloring ; 4-regular graph ; maximum degree * ams subject classification . * 05c15 [ theorem]corollary [ theorem]proposition = 0.5 cm
| 144
|
1508.03733
|
conformational properties of regular dendrimers and more general hyperbranched polymer stars with gaussian statistics for the spacer chains between branching points are revisited numerically . we investigate the scaling for asymptotically long chains especially for fractal dimensions @xmath0 ( marginally compact ) and @xmath1 ( diffusion limited aggregation ) . power - law stars obtained by imposing the number of additional arms per generation are compared to truly self - similar stars . we discuss effects of weak excluded volume interactions and sketch the regime where the gaussian approximation should hold in dense solutions and melts for sufficiently large spacer chains .
| 102
|
0902.4799
|
we consider boson stars and black holes in scalar electrodynamics with a v - shaped scalar potential . the boson stars come in two types , having either ball - like or shell - like charge density . we analyze the properties of these solutions and determine their domains of existence . when mass and charge become equal , the space - times develop a throat . the shell - like solutions need not be globally regular , but may possess a horizon . the space - times then consist of a schwarzschild - type black hole in the interior , surrounded by a shell of charged matter , and thus a reissner - nordstrm - type space - time in the exterior . these solutions violate black hole uniqueness . the mass of the black hole solutions is related to the mass of the regular shell - like solutions by a mass formula of the type first obtained within the isolated horizon framework .
| 165
|
cond-mat0409392
|
the band structure of semimagnetic hg@xmath0mn@xmath1te / hg@xmath2cd@xmath3te type - iii quantum wells has been calculated using eight - band @xmath4 model in an envelope function approach . details of the band structure calculations are given for the mn free case ( @xmath5 ) . a mean field approach is used to take the influence of the @xmath6 exchange interaction on the band structure of qw s with low mn concentrations into account . the calculated landau level fan diagram and the density of states of a hg@xmath7mn@xmath8te / hg@xmath9cd@xmath10te qw are in good agreement with recent experimental transport observations . the model can be used to interpret the mutual influence of the two - dimensional confinement and the @xmath6 exchange interaction on the transport properties of hg@xmath0mn@xmath1te / hg@xmath2cd@xmath3te qw s .
| 133
|
1302.2685
|
in order to promote our understanding on electronic structure of actinide dioxides , we construct a tight - binding model composed of actinide @xmath0 and oxygen @xmath1 electrons , which is called @xmath2-@xmath3 model . after the diagonalization of the @xmath2-@xmath3 model , we compare the eigenenergies in the first brillouin zone with the results of relativistic band - structure calculations . here we emphasize a key role of @xmath2-@xmath3 hybridization in order to understand the electronic structure of actinide dioxides . in particular , it is found that the position of energy levels of @xmath4 and @xmath5 states determined from crystalline electric field potentials depends on the @xmath2-@xmath3 hybridization . we clarify the condition on the @xmath2-@xmath3 hybridization to explain the electronic structure which is consistent with the local crystalline electric field state . we briefly discuss the region of the absolute values of the slater - koster integrals for @xmath2-@xmath3 hybridization concerning the appearance of octupole ordering in npo@xmath6 .
| 162
|
math-ph0512058
|
the method of efficient description of long - term behavior of solutions of the non - linear first order ode @xmath0 for arbitrary periodic @xmath1 is discussed . the criterion enabling one to separate and identify the qualitatively different solutions is established . the applications of the method to the modeling of dynamics of overdamped josephson junctions in superconductors are outlined . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ long - term behavior + of solutions of the equation @xmath0 + with periodic @xmath1 + and the modeling of dynamics + of overdamped josephson junctions : + _ unlectured notes _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ s.i . tertychniy + russia , vniiftri
| 235
|
cond-mat0207379
|
the resistivity and hall effect in cenisn are measured at temperatures down to 35 mk and in magnetic fields up to 20 t with the current applied along the _ b _ axis . the resistivity at zero field exhibits quadratic temperature dependence below @xmath00.16 k with a huge coefficient of the @xmath1 term ( 54 @xmath2@xmath3cm / k@xmath4 ) . the resistivity as a function of field shows an anomalous maximum and dip , the positions of which vary with field directions . shubnikov - de haas ( sdh ) oscillations with a frequency _ f _ of @xmath0100 t are observed for a wide range of field directions in the _ ac _ and _ bc _ planes , and the quasiparticle mass is determined to be @xmath010 - 20 _ m_@xmath5 . the carrier density is estimated to be @xmath010@xmath6 electron / ce . in a narrow range of field directions in the _ ac _ plane , where the magnetoresistance - dip anomaly manifests itself clearer than in other field directions , a higher - frequency ( @xmath7 ) sdh oscillation is found at high fields above the anomaly . this observation is discussed in terms of possible field - induced changes in the electronic structure .
| 211
|
cond-mat9910391
|
phase diagram of half - doped perovskite manganites is studied within the extended double - exchange model . to demonstrate the role of orbital degrees of freedom both one- and two - orbital models are examined . a rich phase diagram is obtained in the mean - filed theory at zero temperature as a function of @xmath0 ( antiferromagnetic ( afm ) superexchange interaction ) and @xmath1 ( intersite coulomb repulsion ) . for the one - orbital model a charge - ordered ( co ) state appears at any value of @xmath1 with different types of magnetic order which changes with increasing @xmath0 from ferromagnetic ( f ) to afm ones of the types a , c and g . the orbital degeneracy results in appearance of a new ce - type spin order that is favorable due to opening of the `` dimerization '' gap at the fermi surface . in addition , the co state appears only for @xmath2 for f and ce states while c - type afm state disappears and a - type afm state is observed only at small values of @xmath1 as a charge disordered one . the relevance of our results to the experimental data are discussed . 2
| 207
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