论文标题
在非马克维亚环境中自旋链的量子能电流和量子相干性
Quantum energy current and quantum coherence of a spin chain in a non-Markovian environment
论文作者
论文摘要
我们研究了量子自旋链及其周围的非马克维亚有限温度浴场之间能量电流的行为,以及它与系统相干动力学的关系。具体来说,系统和浴缸都被认为最初是在温度下的热平衡中,分别是$ t_s $和$ t_b $。该模型在开放系统中量子系统向热平衡的进化研究起着基本作用。非马克维亚量子状态扩散(NMQSD)方程方法用于计算自旋链的动力学。分别分析了浴浴非标志性,温度差和系统培养基相互作用强度对能量电流和温暖浴中的相干性的影响。在这两种情况下,我们的计算结果都表明,强的非马克维亚性,弱系统托架相互作用和低温差将有助于保持系统的连贯性,并且对应于较小的能量电流。有趣的是,温暖的浴场破坏了连贯性,而冷浴有助于产生连贯性。此外,分析了dzyaloshinskii-moriya($ dm $)的相互作用以及能量电流和相干性的外部磁场的影响。由于$ dm $相互作用和磁场引起的系统能量的改善,能量电流和连贯性都会发生变化。值得注意的是,最低的连贯性对应于导致一阶相变的临界磁场。
We investigate the behavior in time of the energy current between a quantum spin chain and its surrounding non-Markovian, finite temperature baths, together with its relationship to the coherence dynamics of the system. To be specific, both the system and the baths are assumed to be initially in thermal equilibrium at temperature $T_s$ and $T_b$, respectively. This model plays a fundamental role for the study of quantum system evolution towards thermal equilibrium in an open system. The non-Markovian quantum state diffusion (NMQSD) equation approach is used to calculate the dynamics of the spin chain. The effects of bath non-Markovinity, temperature difference and system-bath interaction strength on the energy current and the coherence in warm and cold baths are analyzed, respectively. For both cases, our calculation results show that strong non-Markovianity, weak system-bath interaction and low temperature difference will be helpful to maintain the coherence of the system and correspond to a small energy current. Interestingly, the warm baths destroy the coherence while the cold baths help to generate coherence. Furthermore, the effects of the Dzyaloshinskii-Moriya ($DM$) interaction and the external magnetic field on the energy current and coherence are analyzed. Both energy current and coherence will change due to the improvement of the system energy induced by the $DM$ interaction and magnetic field. Significantly, the lowest coherence corresponds to the critical magnetic field which causes the first order phase transition.