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J Phys Condens Matter ; 31(7): 075801, 2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30524084


After a quench of transverse field, the asymptotic long-time state of the Ising model displays a transition from a ferromagnetic phase to a paramagnetic phase as the post-quench field strength increases, which is revealed by the vanishing of the order parameter defined as the averaged magnetization over time. We estimate the critical behavior of the magnetization at this nonequilibrium phase transition by using the mean-field approximation. In the vicinity of the critical field, the magnetization vanishes as the inverse of a logarithmic function, which is significantly distinguished from the critical behavior of order parameter at the corresponding equilibrium phase transition, i.e. a power-law function.

Artigo em Inglês | MEDLINE | ID: mdl-24032781


It is demonstrated in many thermodynamic textbooks that the equivalence of the different ensembles is achieved in the thermodynamic limit. In this present work we discuss the inequivalence of microcanonical and canonical ensembles in a finite ultracold system at low energies. We calculate the microcanonical momentum distribution function (MDF) in a system of identical fermions (bosons). We find that the microcanonical MDF deviates from the canonical one, which is the Fermi-Dirac (Bose-Einstein) function, in a finite system at low energies where the single-particle density of states and its inverse are finite.

J Phys Condens Matter ; 25(5): 055601, 2013 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-23262414


The ground state properties of the Hubbard model with or without long-range interactions in the regime with strongly repulsive on-site interactions are investigated by means of the exact diagonalization method. We show that the appearance of N-crests in the density profile of a trapped N-fermion system is a natural result of 'fermionization' between antiparallel-spin fermions in the strongly repulsive limit and cannot be taken as the only signature of the Wigner crystal phase, as the static structure factor does not show any signature of crystallization. In contrast, both the density distribution and the static structure factor of the Hubbard model with strong long-range interactions display clear signatures of the Wigner crystal phase. Our results indicate the important role of long-range interaction in the formation of the Wigner crystal phase.

Phys Rev Lett ; 101(20): 206402, 2008 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-19113360


Motivated by the large interest in the nonequilibrium dynamics of low-dimensional quantum many-body systems, we present a fully microscopic theoretical and numerical study of the charge and spin dynamics in a one-dimensional ultracold Fermi gas following a quench. Our approach, which is based on time-dependent current-density-functional theory, is applicable well beyond the linear-response regime and produces both spin-charge separation and spin-drag-induced broadening of the spin packets.

Phys Rev Lett ; 98(3): 030404, 2007 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-17358665


The Luther-Emery liquid is a state of matter that is predicted to occur in one-dimensional systems of interacting fermions and is characterized by a gapless charge spectrum and a gapped spin spectrum. In this Letter we discuss a realization of the Luther-Emery phase in a trapped cold-atom gas. We study by means of the density-matrix renormalization-group technique a two-component atomic Fermi gas with attractive interactions subject to parabolic trapping inside an optical lattice. We demonstrate how this system exhibits compound phases characterized by the coexistence of spin pairing and atomic-density waves. A smooth crossover occurs with increasing magnitude of the atom-atom attraction to a state in which tightly bound spin-singlet dimers occupy the center of the trap. The existence of atomic-density waves could be detected in the elastic contribution to the light-scattering diffraction pattern.

Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-516033


The effects of tumor promoter TPA, MZR and PB on gap junction intercellular communication in NIH/3T3 cells were studied using the scrape-loading/dye transfer technique. All of these 3 agents were shown to cause a dose-dependent inhibition of the intercellular communication. The blockage of intercellular communication induced by TPA and MZR was inhibited in the presence of the protein kinase C inhibitor, staurosporine or palmitoyl carnitine, but not inhibited in the casexinduced by PB. The results suggest that the serape-loading/dye transfer technique may be used as a rapid screening assay to detect the tumor promoters and protein kinase C may be involved in the genesis of intercellular communication blockage induced by TPA ane MZR, but not by PB.