We investigate the Landau-Zener tunnelling of two-component Bose-Einstein condensates （BECs） in optical lattices. In the neighborhood of the Brillouin zone edge, the system can be reduced to two coupled nonlinear tw...We investigate the Landau-Zener tunnelling of two-component Bose-Einstein condensates （BECs） in optical lattices. In the neighborhood of the Brillouin zone edge, the system can be reduced to two coupled nonlinear two-level models. From the models, we calculate the change of the tunnelling probability for each component with the linear sweeping rate. It is found that the probability for each component exhibits regular oscillating behavior for the larger sweeping rate, but for smaller rate the oscillation is irregular. Moreover, the asymmetry of the tunnelling between the two components can be induced by the unbalanced initial populations or the inequality of the two self-interactions when the cross-interaction between the components exists. The result can not be found in the single component BECs.展开更多
当前脉冲星领域一个重要的研究热点是磁星.本文在朱翠等(Zhu C,Gao Z F,Li X D,Wang N,Yuan J P,Peng Q H 2016 Mod.Phys.Lett.311650070)工作的基础上,重新研究了磁星超强磁场下(B>>B_(cr),B_(cr)是电子的.量子临界磁场)电子朗...当前脉冲星领域一个重要的研究热点是磁星.本文在朱翠等(Zhu C,Gao Z F,Li X D,Wang N,Yuan J P,Peng Q H 2016 Mod.Phys.Lett.311650070)工作的基础上,重新研究了磁星超强磁场下(B>>B_(cr),B_(cr)是电子的.量子临界磁场)电子朗道能级的稳定性及其对电子压强的影响.首先,对弱磁场极限下(B<<B_(cr))中子星内部电子压强进行必要的回顾;然后,通过引入电子朗道能级稳定性系数g_(v)和Dirac-δ函数,推导出在超强磁场下修正的相对论电子压强P_(e)的表达式,给出表达式适用条件:物质密度P≥10^(7)g·cm^(-3).和B_(cr)≤B<10^(17)G(1 G=10^(-4)T).超强磁场通过修正相对论电子的相空间,提高了电子数密度n_(e),而n_(e)的增加意味着Pe的增加.利用修正的电子压强表达式,讨论了超强磁场下费米子自旋极化现象、电子磁化现象以及超强磁场对物态方程的修正.最后,本文的结果与其他类似工作进行对比,并对未来的工作进行展望.本文的研究将为磁星以及强磁化白矮星的物态方程和热演化的探索提供极有价值的参考,将为普通射电脉冲星等离子磁层数值模拟、高磁场脉冲星辐射机制等相关研究提供有用的信息.展开更多
基金Supported by Natural Science Foundation of Shaanxi University of Science and Technology under Grant No.SUST-ZX08-27
文摘We investigate the Landau-Zener tunnelling of two-component Bose-Einstein condensates （BECs） in optical lattices. In the neighborhood of the Brillouin zone edge, the system can be reduced to two coupled nonlinear two-level models. From the models, we calculate the change of the tunnelling probability for each component with the linear sweeping rate. It is found that the probability for each component exhibits regular oscillating behavior for the larger sweeping rate, but for smaller rate the oscillation is irregular. Moreover, the asymmetry of the tunnelling between the two components can be induced by the unbalanced initial populations or the inequality of the two self-interactions when the cross-interaction between the components exists. The result can not be found in the single component BECs.
文摘当前脉冲星领域一个重要的研究热点是磁星.本文在朱翠等(Zhu C,Gao Z F,Li X D,Wang N,Yuan J P,Peng Q H 2016 Mod.Phys.Lett.311650070)工作的基础上,重新研究了磁星超强磁场下(B>>B_(cr),B_(cr)是电子的.量子临界磁场)电子朗道能级的稳定性及其对电子压强的影响.首先,对弱磁场极限下(B<<B_(cr))中子星内部电子压强进行必要的回顾;然后,通过引入电子朗道能级稳定性系数g_(v)和Dirac-δ函数,推导出在超强磁场下修正的相对论电子压强P_(e)的表达式,给出表达式适用条件:物质密度P≥10^(7)g·cm^(-3).和B_(cr)≤B<10^(17)G(1 G=10^(-4)T).超强磁场通过修正相对论电子的相空间,提高了电子数密度n_(e),而n_(e)的增加意味着Pe的增加.利用修正的电子压强表达式,讨论了超强磁场下费米子自旋极化现象、电子磁化现象以及超强磁场对物态方程的修正.最后,本文的结果与其他类似工作进行对比,并对未来的工作进行展望.本文的研究将为磁星以及强磁化白矮星的物态方程和热演化的探索提供极有价值的参考,将为普通射电脉冲星等离子磁层数值模拟、高磁场脉冲星辐射机制等相关研究提供有用的信息.
