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arXiv 1206.2707cond-mat.stat-mechquant-ph
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强耦合区开放量子系统的平衡态

The equilibrium states of open quantum systems in the strong coupling regime

Y. Subasi, C. H. Fleming, J. M. Taylor, B. L. Hu

摘要:

在本工作中,我们研究了在强耦合区域中耦合到热库的开放量子系统的晚期定态。一般来说,如果到热库的耦合是非零的,或者等效地,如果弛豫时间尺度是有限的,则这样的系统不一定弛豫到玻尔兹曼分布。利用各种适用于非马尔可夫过程的非平衡形式,我们证明了从封闭系统=系统+环境的乘积态开始,随着环境处于热态,由环境粗粒化产生的开放系统将在后期向平衡态演化。这种状态可以表示为在环境温度下封闭系统热状态的降低状态。对于一个线性(谐波)系统和环境,这是完全可解的,我们能够严格的方式表明,所有的开放系统的多时间的相关性朝着那些封闭系统的热状态演变。多时间相关性在非马尔可夫机制中特别重要,因为它们不能由单时间相关性的动态产生。对于更一般的系统,这不能被精确地解决,我们能够提供一个一般的证明,所有的开放系统的单时间相关性发展到那些封闭系统的热状态,一阶的弛豫速率。对于零温度水库的特殊情况,我们能够明确地构造约化的封闭系统的热态的环境相关性。

英文摘要:

In this work we investigate the late-time stationary states of open quantum systems coupled to a thermal reservoir in the strong coupling regime. In general such systems do not necessarily relax to a Boltzmann distribution if the coupling to the thermal reservoir is non-vanishing or equivalently if the relaxation timescales are finite. Using a variety of non-equilibrium formalisms valid for non-Markovian processes, we show that starting from a product state of the closed system = system + environment, with the environment in its thermal state, the open system which results from coarse graining the environment will evolve towards an equilibrium state at late-times. This state can be expressed as the reduced state of the closed system thermal state at the temperature of the environment. For a linear (harmonic) system and environment, which is exactly solvable, we are able to show in a rigorous way that all multi-time correlations of the open system evolve towards those of the closed system thermal state. Multi-time correlations are especially relevant in the non-Markovian regime, since they cannot be generated by the dynamics of the single-time correlations. For more general systems, which cannot be exactly solved, we are able to provide a general proof that all single-time correlations of the open system evolve to those of the closed system thermal state, to first order in the relaxation rates. For the special case of a zero-temperature reservoir, we are able to explicitly construct the reduced closed system thermal state in terms of the environmental correlations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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