论文标题
平衡和非平衡环境对通过Leggett-Garg不平等的宏观现实主义的影响
Influence of equilibrium and nonequilibrium environments on macroscopic realism through the Leggett-Garg inequalities
论文作者
论文摘要
我们通过两个相互作用的量子器系统中的两次和三次的Leggett-Garg不平等（LGI）研究了宏观现实主义（大分）。两个量子位与两个骨（热或光子）浴或费米子（电子）浴耦合。我们研究平衡环境和非平衡环境如何影响LGI。表征非平衡条件的一种方法是通过温度差（对于玻体浴）或化学电位差（对于费米子浴室）。我们还研究了非平衡环境产生的热或颗粒电流和熵产生速率。 LGI的分析形式和基于世俗近似之外的量子主方程的LGI的最大值。 LGI函数和相应的最大值具有分离的贡献，该部分描述了相干演化以及描述系统和环境之间耦合的部分。环境耦合部分可以来自平衡环境或非平衡环境。非平衡动力学通过超出lindblad形式的Bloch-Redfield方程来量化。我们发现，通过温度差或化学势差量化的非平衡性可能导致LGI违规或LGI的最大值的增加，从而从保留LGI的某些平衡情况下恢复量子性质。相应的非平衡热力学成本通过非零熵的生产率进行了量化。我们对非平衡促进的LGI违规的发现提出了一种设计量子信息处理和量子计算设备的新策略，以长期维持量子性质和量子相关性。
We study the macroscopic realism (macrorealism) through the two- and three-time Leggett-Garg inequalities (LGIs) in a two interacting qubits system. The two qubits are coupled either with two bosonic (thermal or photonic) baths or fermionic (electronic) baths. We study both how the equilibrium and nonequilibrium environments influence the LGIs. One way to characterize the nonequilibrium condition is by the temperature difference (for the bosonic bath) or the chemical potential difference (for the fermionic bath). We also study the heat or particle current and the entropy production rate generated by the nonequilibrium environments. Analytical forms of LGIs and the maximal value of LGIs based on the quantum master equation beyond the secular approximation are derived. The LGI functions and the corresponding maximal value have separated contributions, the part describing the coherent evolution and the part describing the coupling between the system and environments. The environment-coupling part can be from the equilibrium environment or the nonequilibrium environment. The nonequilibrium dynamics is quantified by the Bloch-Redfield equation which is beyond the Lindblad form. We found that the nonequilibriumness quantified by the temperature difference or the chemical potential difference can lead to the LGIs violations or the increase of the maximal value of LGIs, restoring the quantum nature from certain equilibrium cases where LGIs are preserved. The corresponding nonequilibrium thermodynamic cost is quantified by the nonzero entropy production rate. Our finding of the nonequilibrium promoted LGIs violations suggests a new strategy for the design of quantum information processing and quantum computational devices to maintain the quantum nature and quantum correlations for long.
