By taking into account the two-spin interaction in the transverse Ising model （TIM）, the influence of the defect layers （including JB and ΩB） on the polarization and Curie temperature are calculated numerically, ...By taking into account the two-spin interaction in the transverse Ising model （TIM）, the influence of the defect layers （including JB and ΩB） on the polarization and Curie temperature are calculated numerically, within the framework of the decoupling approximation under Green＇s function. The numerical results show that the polarization and Curie temperature will both become large sensitively due to the large values of JB and the small value of ΩB of the defect layers. Meanwhile, the dependence of the crossover values of the exchange interaction JA, the transverse field ΩA of the bulk material on the exchange interaction JB and the transverse field ΩB of the defect layers are shown in 3-Dimensional （3-D） figures for the first time. Moreover, the transition features of the ferroelectric thin film with defect layers are presented.展开更多
Motivated by the recent experiments realized in a fiat-bottomed optical trap [Science 347 （2015） 167; Nat. Commun. 6 （2015） 6162], we study the ground state of polar-core spin vortex of quasi-2D spin-2 condensate ...Motivated by the recent experiments realized in a fiat-bottomed optical trap [Science 347 （2015） 167; Nat. Commun. 6 （2015） 6162], we study the ground state of polar-core spin vortex of quasi-2D spin-2 condensate in a homogeneous trap plus a weak magnetic field. The exact spatial distribution of local spin is obtained and the vortex core are observed to decrease with the growth of the effective spin-spin interaction. For the larger effective spin-spin interaction, the spatial distribution of spin magnitude in spin-2 condensate we obtained agrees well with that of spin-1 condensate in a homogeneous trap, where a polar-core spin vortex was schematically demonstrated as a fully-magnetized planar spin texture with a zero-spin core. The effective spin-spin interaction is proportional to both the bare spin-spin interaction and the radius of the homogeneous trap, simultaneously. Thus the polar-core spin vortex we obtained can be easily controlled by the radius of the trap.展开更多
We investigate tunneling and self-trapping of superfluid Fermi gases under a two-mode ansatz in different regimes of the crossover from Bardeen-Cooper-Schrieffer （BCS） superfluid to Bose-Einstein condensates （BEC）...We investigate tunneling and self-trapping of superfluid Fermi gases under a two-mode ansatz in different regimes of the crossover from Bardeen-Cooper-Schrieffer （BCS） superfluid to Bose-Einstein condensates （BEC）. Starting from a generalized equation of state, we derive the coupled equations of relative atom-pair number and relative phase about superfluid Fermi gases in a double-well system and then classify the different oscillation behaviors by the tunneling strength and interactions between atoms. Tunneling and self-trapping behaviors are considered in the whole BCS-BEC crossover in the ease of a symmetric double-well potential. We show that the nonlinear interaction between atoms makes the self-trapping more easily realized in BCS regime than in the BEC regime and stability analysis is also given.展开更多
文摘By taking into account the two-spin interaction in the transverse Ising model （TIM）, the influence of the defect layers （including JB and ΩB） on the polarization and Curie temperature are calculated numerically, within the framework of the decoupling approximation under Green＇s function. The numerical results show that the polarization and Curie temperature will both become large sensitively due to the large values of JB and the small value of ΩB of the defect layers. Meanwhile, the dependence of the crossover values of the exchange interaction JA, the transverse field ΩA of the bulk material on the exchange interaction JB and the transverse field ΩB of the defect layers are shown in 3-Dimensional （3-D） figures for the first time. Moreover, the transition features of the ferroelectric thin film with defect layers are presented.
基金Supported by the National Natural Science Foundation of China under Grant No.11274095the Key Scientific Research Project of Henan Province of China under Grant No.16A140011the High Performance Computing Center of Henan Normal University
文摘Motivated by the recent experiments realized in a fiat-bottomed optical trap [Science 347 （2015） 167; Nat. Commun. 6 （2015） 6162], we study the ground state of polar-core spin vortex of quasi-2D spin-2 condensate in a homogeneous trap plus a weak magnetic field. The exact spatial distribution of local spin is obtained and the vortex core are observed to decrease with the growth of the effective spin-spin interaction. For the larger effective spin-spin interaction, the spatial distribution of spin magnitude in spin-2 condensate we obtained agrees well with that of spin-1 condensate in a homogeneous trap, where a polar-core spin vortex was schematically demonstrated as a fully-magnetized planar spin texture with a zero-spin core. The effective spin-spin interaction is proportional to both the bare spin-spin interaction and the radius of the homogeneous trap, simultaneously. Thus the polar-core spin vortex we obtained can be easily controlled by the radius of the trap.
基金Supported by Supported by National Natural Science Foundation of China under Grant Nos. 10864006,11047101,11091240227,and11105039by Ph.D. Program Scholarship Fund of East China Normal University under Grant No. 20080044by Research Fund of Jiangsu University of Science and Technology under Grant No. 35051002
文摘We investigate tunneling and self-trapping of superfluid Fermi gases under a two-mode ansatz in different regimes of the crossover from Bardeen-Cooper-Schrieffer （BCS） superfluid to Bose-Einstein condensates （BEC）. Starting from a generalized equation of state, we derive the coupled equations of relative atom-pair number and relative phase about superfluid Fermi gases in a double-well system and then classify the different oscillation behaviors by the tunneling strength and interactions between atoms. Tunneling and self-trapping behaviors are considered in the whole BCS-BEC crossover in the ease of a symmetric double-well potential. We show that the nonlinear interaction between atoms makes the self-trapping more easily realized in BCS regime than in the BEC regime and stability analysis is also given.
