We investigate the particle-hole pair excitations of dipolar molecules in an optical lattice, which can be described with an extended Bose-Hubbard model. For strong enough dipole-dipole interaction, the particle-hole ...We investigate the particle-hole pair excitations of dipolar molecules in an optical lattice, which can be described with an extended Bose-Hubbard model. For strong enough dipole-dipole interaction, the particle-hole pair excitations can form bound states in one and two dimensions. With decreasing dipole-dipole interaction, the energies of the bound states increase and merge into the particle-hole continuous spectrum gradually. The existence regions, the energy spectra and the wave functions of the bound states are carefully studied and the symmetries of the bound states are analyzed with group theory. For a given dipole-dipole interaction, the number of bound states varies in momentum space and a number distribution of the bound states is illustrated. We also discuss how to observe these bound states in future experiments.展开更多
Reflection and transmission are two behaviors of wave propagating to an interface. The immiscible binary mixtures of Bose–Einstein condensates can form the symmetry-breaking state, in which the domain wall on the cen...Reflection and transmission are two behaviors of wave propagating to an interface. The immiscible binary mixtures of Bose–Einstein condensates can form the symmetry-breaking state, in which the domain wall on the center can serve as the interface. In this study, we explore in detail the propagation of a dark soliton interacting with the domain wall in the harmonic trap. We find that the low-energy dark soliton is easy to form the transmission and the high-energy dark soliton trends to reflect from the domain wall. Both reflection and transmission of dark soliton on the domain wall induce the sound radiation. But the sound radiation in the reflection derives from the collective oscillation of condensates, and it in the transmission comes not only from the collective oscillation, but also from the condensate filling in the dark soliton.展开更多
Topological superfluid state is different from the normal superfluid one due to the excitation energy gap on the boundary.How to obtain the topological superfluid state by using spin-orbit coupling to control the s-wa...Topological superfluid state is different from the normal superfluid one due to the excitation energy gap on the boundary.How to obtain the topological superfluid state by using spin-orbit coupling to control the s-waves paired mass-imbalanced Fermi gas is a recent novel topic.In this paper,we study the topological superfluid phase diagram of two-dimensional mass-imbalanced Fermi gas with Rashba spin-orbit coupling at zero temperature.We find that due to the competition among mass imbalance,pairing interaction and spin-orbit coupling,there is a double-well structure in the thermodynamic potential,which affects the properties of the ground state of the system.We comprehensively give the phase diagrams of the system on the plane of spin-orbit coupling and chemical potential,and the phase diagrams on the plane of the reduced mass ratio and two-body binding energy.This study not only points out the stable region of topolog-ical superfluid state of mass-imbalanced Fermi gas,but also provides a detailed theoretical basis for better observation of topological superfluid state in experiments.展开更多
基金supported by the National Basic Research Program of China (Grant Nos. 2011CB921502)the National Natural Science Foundation of China (Grant No. 10934010)+1 种基金the Joint Research Projects of the National Natural Science Foundation of ChinaHong Kong Research Grant Council (Grant Nos. 11061160490 and N-HKU748/10)
文摘We investigate the particle-hole pair excitations of dipolar molecules in an optical lattice, which can be described with an extended Bose-Hubbard model. For strong enough dipole-dipole interaction, the particle-hole pair excitations can form bound states in one and two dimensions. With decreasing dipole-dipole interaction, the energies of the bound states increase and merge into the particle-hole continuous spectrum gradually. The existence regions, the energy spectra and the wave functions of the bound states are carefully studied and the symmetries of the bound states are analyzed with group theory. For a given dipole-dipole interaction, the number of bound states varies in momentum space and a number distribution of the bound states is illustrated. We also discuss how to observe these bound states in future experiments.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61565007,11875149,11747079,and 11874127)the Science Fund from the Department of Science and Technology of Jiangxi Province,China(Grant Nos.20162BCB23049 and 20171ACB21045)+1 种基金the Youth Jinggang Scholars Program in Jiangxi Province,Chinathe Program of Qingjiang Excellent Yong Talents,Jiangxi University of Science and Technology,China
文摘Reflection and transmission are two behaviors of wave propagating to an interface. The immiscible binary mixtures of Bose–Einstein condensates can form the symmetry-breaking state, in which the domain wall on the center can serve as the interface. In this study, we explore in detail the propagation of a dark soliton interacting with the domain wall in the harmonic trap. We find that the low-energy dark soliton is easy to form the transmission and the high-energy dark soliton trends to reflect from the domain wall. Both reflection and transmission of dark soliton on the domain wall induce the sound radiation. But the sound radiation in the reflection derives from the collective oscillation of condensates, and it in the transmission comes not only from the collective oscillation, but also from the condensate filling in the dark soliton.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11875149, 11874127, 52061014, and 61565007)the Youth Jing-gang Scholars Program of Jiangxi Province, Chinathe Program of Qing-jiang Excellent Young Talents, Jiangxi University of Science and Technology
文摘Topological superfluid state is different from the normal superfluid one due to the excitation energy gap on the boundary.How to obtain the topological superfluid state by using spin-orbit coupling to control the s-waves paired mass-imbalanced Fermi gas is a recent novel topic.In this paper,we study the topological superfluid phase diagram of two-dimensional mass-imbalanced Fermi gas with Rashba spin-orbit coupling at zero temperature.We find that due to the competition among mass imbalance,pairing interaction and spin-orbit coupling,there is a double-well structure in the thermodynamic potential,which affects the properties of the ground state of the system.We comprehensively give the phase diagrams of the system on the plane of spin-orbit coupling and chemical potential,and the phase diagrams on the plane of the reduced mass ratio and two-body binding energy.This study not only points out the stable region of topolog-ical superfluid state of mass-imbalanced Fermi gas,but also provides a detailed theoretical basis for better observation of topological superfluid state in experiments.
