Han Liping, Zou Jian, Li Hai, Shao Bin
School of Physics, Beijing Institute of Technology, Beijing 100081, China.
School of Science, Tianjin University of Technology, Tianjin 300384, China.
Entropy (Basel). 2020 Aug 15;22(8):895. doi: 10.3390/e22080895.
Based on conditional past-future (CPF) correlations, we study the non-Markovianity of a central spin coupled to an isotropic Lipkin-Meshkov-Glick (LMG) bath. Although the dynamics of a system is always non-Markovian, it is found that some measurement time intervals considering a specific process, with respect to a particular set of CPF measurement operators, can be zero, which means that in this case the non-Markovianity of the system could not be detected. Furthermore, the initial system-bath correlations only slightly influence the non-Markovianity of the system in our model. Significantly, it is also found that the dynamics of the system for LMG baths, initially in the ground states corresponding to the symmetric phase and symmetry broken phase, exhibit different properties, and the maximal value of the CPF at the critical point is the smallest, independent of the measurement operator, which means that the criticality can manifest itself by the CPF. Moreover, the effect of bath temperature on the quantum criticality of the CPF depends on the measurement operator.
基于条件过去-未来（CPF）关联，我们研究了与各向同性Lipkin-Meshkov-Glick（LMG）浴耦合的中心自旋的非马尔可夫性。尽管系统的动力学总是非马尔可夫的，但发现对于特定的一组CPF测量算符，考虑特定过程的某些测量时间间隔可以为零，这意味着在这种情况下无法检测到系统的非马尔可夫性。此外，在我们的模型中，初始系统-浴关联对系统的非马尔可夫性影响很小。值得注意的是，还发现最初处于对应于对称相和对称破缺相的基态的LMG浴系统的动力学表现出不同的性质，并且临界点处CPF的最大值最小，与测量算符无关，这意味着临界性可以通过CPF表现出来。此外，浴温度对CPF量子临界性的影响取决于测量算符。
