Toward relaxation asymmetry: Heating is faster than cooling
Toward relaxation asymmetry: Heating is faster than cooling
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DOI：
10.1103/physrevresearch.3.043160
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发表时间：
2021-02
影响因子：
4.2
通讯作者：
T. Van Vu;Yoshihiko Hasegawa
中科院分区：
文献类型：
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作者：
T. Van Vu;Yoshihiko Hasegawa
朗之万系统在稳定最小值附近发现了热弛豫向平衡的不对称性[Phys.莱特牧师。 125, 110602 (2020)]。已经表明，在初始分布的不平衡程度相同的情况下，从较低温度状态（加热）的弛豫比从较高温度状态（冷却）的弛豫更快。在这项研究中，我们阐明了主方程描述的离散状态马尔可夫系统的松弛不对称性。我们严格证明，对于任意二态系统，加热比冷却更快，而对于具有两个以上不同能级的系统，弛豫不对称性不再普遍。此外，对于能级退化为两种能态的系统，我们发现存在能隙的临界阈值。根据能隙的大小，加热可能比冷却更快或更慢，而与状态之间的转变速率无关。我们的结果阐明了离散态系统的弛豫不对称性，并揭示了热弛豫固有的几个隐藏特征。
An asymmetry in thermal relaxation toward equilibrium has been uncovered for Langevin systems near stable minima [Phys. Rev. Lett. 125, 110602 (2020)]. It has been shown that, given the same degree of nonequilibrium of the initial distributions, relaxation from a lower temperature state (heating) is faster than that from a higher temperature state (cooling). In this study, we elucidate this relaxation asymmetry for discrete-state Markovian systems described by the master equation. We rigorously prove that heating is faster than cooling for arbitrary two-state systems, whereas for systems with more than two distinct energy levels, the relaxation asymmetry is no longer universal. Furthermore, for systems whose energy levels degenerate into two energy states, we find that there exist critical thresholds of the energy gap. Depending on the magnitude of the energy gap, heating can be faster or slower than cooling, irrespective of the transition rates between states. Our results clarify the relaxation asymmetry for discrete-state systems and reveal several hidden features inherent in thermal relaxation.