强耦合条件下非平衡自旋-玻色体系的相干动力学与量子传输研究

As one of classical research objectives in the areas of quantum optics, quantum information, quantum measurement, etc., spin-boson systems significantly own the scientific value to unravel light(phonon)-matter interaction and many-body effects. Recently, scientists begin to pay attention to the influence of quantum coherence on information and energy transfer under the nonequilibrium condition. However, it is yet unclear that under strong system-bath interaction, how quantum coherence in nonequilibrium spin-boson model forms and how the relation of coherence with dynamical transition and nonequilibrium many-body phenomena are established. In this project, we start from the quantum information theory to study transient information transfer and many-body effect in strong coupling spin-boson models, by applying the polaron-transformed quantum master equation and hierarchically functional equation of motion, combined with extended bosonic coherent-state and auxiliary field of full counting statistics. Through analysis of representative information quantities, e.g., quantum correlation, Fisher information and current fluctuations, we try to characterize mechanisms and detail processes of qubits dynamical transition, by interacting with thermally biased baths. Meanwhile, we also exploit the quantitative relation of quantum correlation with quantum many-body phenomena. As a whole, we believe that this project may actively have the theoretical consequences for deeply understanding the effect of quantum coherence on transient information exchange and smart control of nonequilibrium transfer in strongly coupled spin-boson systems.

自旋-玻色体系作为量子光学、量子信息、量子测量等领域的典型对象之一，在揭示光（声）-物质相互作用与多体效应中有着重要的科学价值。近来，科学工作者在非平衡条件下开始关注量子相干性对信息、能量传输的影响。但是，关于非平衡自旋-玻色模型在强耦合下相干性的形成机制，以及如何建立其与动力学转变、非平衡多体现象的内在联系，还尚未清晰。在本项目中，我们将从量子信息理论出发，运用极化子变换量子主方程与级联耦合泛函方程，结合扩展玻色子相干态和全计数统计辅助场等方法，研究强耦合自旋-玻色模型瞬态信息传输与非平衡量子多体效应。通过量子关联、Fisher信息、量子流涨落等典型信息量来刻画量子比特在热力学偏置环境下的动力学转变机制，以及比特与环境信息交互的细致过程。同时，探索建立量子关联与多体效应的定量关系。相信本项目对于深入理解在强耦合条件下自旋-玻色体系的瞬态信息交互与非平衡传输调控具有积极的理论指导意义。

系统-环境强相互作用下小量子体系的非平衡热输运与动力学行为长期以来是量子光学、非平衡统计研究领域的热点之一。在本项目中，我们从量子器件、热力学与动力学等多角度研究了典型小量子体系（包括自旋-玻色模型、电-声作用模型、非平衡三能级模型）中负微分热导、热放大、热整流与芝诺效应等现象。主要结果与科学意义有：i)系统-环境强耦合下循环流对负微分热导与热放大的重要性。强耦合与循环流为实现量子热晶体管及其微观机制提供了一个新的视角。ii)系统-环境强耦合引起的芝诺-反常芝诺动力学转变。强耦合下的非传统指数衰减拓展了芝诺效应的研究思路。iii)给出了线性响应区间热电体系的热力学效率、热放大及其涨落的极限。首次发现了热放大系数涨落的普适行为。这拓展了热电体系的热力学与统计研究方式。iv)热库导致的体系量子相干性对稳恒态热输运有着重要贡献。稳态相干性可以产生热整流效应。这类稳恒态相干性为研究热整流效应提供了新的实现方案。综上所述，我们的研究为深入理解量子小器件的动力学与热输运功能提供了一些新的见解。