查看更多>>摘要：By considering the negative cosmological constant A as a thermodynamic pressure,we study the thermodynam-ics and phase transitions of the D-dimensional dyonic AdS black holes(BHs)with quasitopological electromagnetism in Einstein-Gauss-Bonnet(EGB)gravity.The results indicate that the small/large BH phase transition that is similar to the van der Waals(vdW)liquid/gas phase transition always exists for any spacetime dimensions.Interestingly,we then find that this BH system exhibits a more complex phase structure in 6-dimensional case that is missed in other dimensions.Specifically,it shows for D=6 that we observed the small/intermediate/large BH phase transitions in a specific parame-ter region with the triple point naturally appeared.Moreover,when the magnetic charge turned off,we still observed the small/intermediate/large BH phase transitions and triple point only in 6-dimensional spacetime,which is consistent with the previous results.However,for the dyonic AdS BHs with quasitopological electromagnetism in Einstein-Born-Infeld(EBI)gravity,the novel phase structure composed of two separate coexistence curves observed by Li et al.[Phys.Rev.D 105 104048(2022)]disappeared in EGB gravity.This implies that this novel phase structure is closely related to gravity theories,and seems to have nothing to do with the effect of quasitopological electromagnetism.In addition,it is also true that the critical exponents calculated near the critical points possess identical values as mean field theory.Finally,we con-clude that these findings shall provide some deep insights into the intriguing thermodynamic properties of the dyonic AdS BHs with quasitopological electromagnetism in EGB gravity.
查看更多>>摘要：The dynamics of spin-orbit-coupled Bose-Einstein condensate with parity-time symmetry through a moving obstacle potential is simulated numerically.In the miscible two-component condensate,the formation of the Kármán vortex street is observed in one component,while'the half-quantum vortex street'is observed in the other component.Other patterns of vortex shedding,such as oblique vortex dipoles,V-shaped vortex pairs,irregular turbulence,and combined modes of various wakes,can also be found.The ratio of inter-vortex spacing in one row to the distance between vortex rows is approximately 0.18,which is less than the stability condition 0.28 of classical fluid.The drag force acting on the obstacle potential is simulated.The parametric regions of Kármán vortex street and other vortex patterns are calculated.The range of Kármán vortex street is surrounded by the region of combined modes.In addition,spin-orbit coupling disrupts the symmetry of the system and the gain-loss affects the local particle distribution of the system,which leads to the local symmetry breaking of the system,and finally influences the stability of the Kármán vortex street.Finally,we propose an experimental protocol to realize the Kármán vortex street in a system.
查看更多>>摘要：Extensive numerical simulations and scaling analysis are performed to investigate competitive growth between the linear and nonlinear stochastic dynamic growth systems,which belong to the Edwards-Wilkinson(EW)and Kardar-Parisi-Zhang(KPZ)universality classes,respectively.The linear growth systems include the EW equation and the model of random deposition with surface relaxation(RDSR),the nonlinear growth systems involve the KPZ equation and typical discrete models including ballistic deposition(BD),etching,and restricted solid on solid(RSOS).The scaling exponents are obtained in both the(1+1)-and(2+1)-dimensional competitive growth with the nonlinear growth probability p and the linear proportion 1-p.Our results show that,when p changes from 0 to 1,there exist non-trivial crossover effects from EW to KPZ universality classes based on different competitive growth rules.Furthermore,the growth rate and the porosity are also estimated within various linear and nonlinear growths of cooperation and competition.
查看更多>>摘要：This study investigates the dynamical behaviors of nearest neighbor asymmetric coupled systems in a confined space.First,the study derivative analytical stability and synchronization conditions for the asymmetrically coupled system in an unconfined space,which are then validated through numerical simulations.Simulation results show that asymmetric coupling has a significant impact on synchronization conditions.Moreover,it is observed that irrespective of whether the system is confined,an increase in coupling asymmetry leads to a hastened synchronization pace.Additionally,the study examines the effects of boundaries on the system's collective behaviors via numerical experiments.The presence of bound-aries ensures the system's stability and synchronization,and reducing these boundaries can expedite the synchronization process and amplify its effects.Finally,the study reveals that the system's output amplitude exhibits stochastic resonance as the confined boundary size increases.
查看更多>>摘要：It is found from textbooks and literature that there are three different statements for the third law of thermodynamics,i.e.,the Nernst theorem,the unattainability statement of absolute zero temperature,and the heat capacity statement.It is pointed out that such three statements correspond to three thermodynamic parameters,which are,respectively,the entropy,temperature,and heat capacity,and can be obtained by extrapolating the experimental results of different parameters at ultra-low temperatures to absolute zero.It is expounded that because there is no need for additional assumptions in the derivation of the Nernst equation,the Nernst theorem should be renamed as the Nernst statement.Moreover,it is proved that both the Nernst statement and the heat capacity statement are mutually deducible and equivalent,while the unattainability of absolute zero temperature is only a corollary of the Nernst statement or the heat capacity statement so that it is unsuitably referred to as one statement of the third law of thermodynamics.The conclusion is that the Nernst statement and the heat capacity statement are two equivalent statements of the third law of thermodynamics.
查看更多>>摘要：We explore the impact of pumping beams with different transverse intensity profiles on the performance of the spin-exchange relaxation-free(SERF)atomic magnetometers(AMs).We conduct experiments comparing the traditional Gaus-sian optically-pumped AM with that utilizing the flat-top optically-pumped(FTOP)method.Our findings reveal that the FTOP-based approach outperforms the conventional method,exhibiting a larger response,a narrower magnetic resonance linewidth,and a superior low-frequency noise performance.Specifically,the use of FTOP method leads to a 16％enhance-ment in average sensitivity within 1 Hz-30 Hz frequency range.Our research emphasizes the significance of achieving transverse polarization uniformity in AMs,providing insights for future optimization efforts and sensitivity improvements in miniaturized magnetometers.
查看更多>>摘要：Electron dynamics during non-sequential double ionization(NSDI)is one of the most attractive areas of research in the field of laser-atom or laser-molecule interaction.Based on the classic two-dimensional model,we study the process of NSDI of argon atoms driven by a few-cycle orthogonal two-color laser field composed of 800 nm and 400 nm laser pulses.By changing the relative phase of the two laser pulses,a localized enhancement of NSDI yield is observed at 0.5π and 1.5π,which could be attributed to a rapid and substantial increase in the number of electrons returning to the parent ion within extremely short time intervals at these specific phases.Through the analysis of the electron-electron momentum correlations within different time windows of NSDI events and the angular distributions of emitted electrons in different channels,we observe a more pronounced electron-electron correlation phenomenon in the recollision-induced ionization(RII)channel.This is attributed to the shorter delay time in the RII channel.
查看更多>>摘要：We present a formulation of the single-trajectory entropy using the trajectories ensemble.The single-trajectory en-tropy is affected by its surrounding trajectories via the distribution function.The single-trajectory entropies are studied in two typical potentials,i.e.,harmonic potential and double-well potential,and in viscous environment by interacting tra-jectory method.The results of the trajectory methods are in agreement well with the numerical methods(Monte Carlo simulation and difference equation).The single-trajectory entropies increasing(decreasing)could be caused by absorption(emission)heat from(to)the thermal environment.Also,some interesting trajectories,which correspond to the rare evens in the processes,are demonstrated.
查看更多>>摘要：We report on the optimal production of the Bose and Fermi mixtures with 87Rb and 40K in a crossed optical dipole trap(ODT).We measure the atomic number and lifetime of the mixtures in combination of the spin state|F=9/2,mF=9/2>of 40Kand|1,1>of 87Rb in the ODT,which is larger and longer compared with the combination of the spin state|9/2,9/2>of 40K and|2,2>of 87Rb in the ODT.We observe the atomic numbers of 87Rb and 40K shown in each stage of the sympathetic cooling process while gradually reducing the depth of the optical trap.By optimizing the relative loading time of atomic mixtures in the MOT,we obtain the large atomic number of 40K(～6 × 106)or the mixtures of atoms with an equal number(～1.6 × 106)at the end of evaporative cooling in the ODT.We experimentally investigate the evaporative cooling in an enlarged volume of the ODT via adding a third laser beam to the crossed ODT and found that more atoms(8 × 106)and higher degeneracy(T/TF=0.25)of Fermi gases are obtained.The ultracold atomic gas mixtures pave the way to explore phenomena such as few-body collisions and the Bose-Fermi Hubbard model,as well as for creating ground-state molecules of87Rb40K.
查看更多>>摘要：The thorough exploration of the transverse quality represented by divergence angle has been lacking yet in the energy spread measurement of the relativistic electron beam for laser wakefield acceleration(LWFA).In this work,we fill this gap by numerical simulations based on the experimental data,which indicate that in a C-shape magnet,magnetic field possesses the beam focusing effect,considering that the divergence angle will result in an increase in the full width at half maxima(FWHM)of the electron density distribution in a uniformly isotropic manner,while the length-to-width ratio decreases.This indicates that the energy spread obtained from the electron deflection distance is smaller than the actual value,regardless of the divergence angle.A promising and efficient way to accurately correct the value is presented by considering the divergence angle(for instance,for an electron beam with a length-to-width ratio of 1.12,the energy spread correct from 1.2％to 1.5％),providing a reference for developing the high-quality electron beam source.
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