发表机构
University of Toronto（多伦多大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究在马尔可夫重复相互作用框架下，推导了量子比特与相干环境相互作用的精确解析解，证实环境相干性可作为资源调控稳态制备与能量传递，甚至逆转热流方向。
AI 中文摘要
我们在马尔可夫重复相互作用框架内，研究了量子比特与相干环境通过能量守恒的翻转-翻转相互作用时的弛豫动力学及稳态。我们推导了演化态和稳态的精确解析解，该解对环境相干性而言是非微扰的。研究表明，环境相干性可作为耗散态制备的资源，通过扩展可及稳态的集合实现这一作用。具体而言，相干辅助量子比特（coherent ancillas）可使系统基态布居数超过热库的基态布居数，对应有效温度低于热库温度，同时提升系统稳态纯度，这些效应由系统能量尺度与系统-辅助量子比特耦合的相互作用所调控。不过，我们证明系统的纯度永远无法超过辅助量子比特的纯度。我们进一步分析了该协议的热力学特性，发现环境相干性可改变甚至逆转热传递的自然方向，产生反常热流。值得注意的是，对于固定的相互作用参数，相干性诱导的热流方向由系统与辅助量子比特相干性之间的相对相位决定，而两者相干性的大小则决定了热交换的量。我们的结果确立了环境相干性作为重复相互作用动力学中控制稳态制备与能量传递的一种资源。
英文摘要
We investigate the relaxation dynamics and steady state of a qubit interacting with a coherent environment through an energy-conserving flip-flop interaction within the Markovian repeated-interaction framework. We derive an exact analytical solution for the evolving and stationary state, nonperturbative in the environmental coherence. We show that environmental coherence provides a resource for dissipative state preparation by expanding the set of accessible steady states. In particular, coherent ancillas can increase the system ground- state population beyond that of the bath, corresponding to an effective temperature below the bath temperature, and enhance its steady-state purity, with these effects controlled by the interplay between the system energy scale and the system-ancilla coupling. Nevertheless, we prove that the purity of the system can never exceed the purity of the ancilla. We further analyze the thermodynamics of the protocol and show that environmental coherence can modify and even reverse the natural direction of heat transfer, giving rise to anomalous heat flow. Remarkably, for fixed interaction parameters, the direction of the coherence-induced heat transfer is governed by the relative phase between the system and ancilla coherence, whereas their magnitudes determine the amount of heat exchanged. Our results establish environmental coherence as a resource for controlling steady-state preparation and energy transfer in repeated-interaction dynamics.
Comments24 pages, 11 figures
