AI 中文总结
该研究基于动力学生成函数，建立了孤立量子粒子与经典布朗粒子动力学相变的统一描述，揭示了单粒子量子系统中可出现通常关联多体系统的动力学量子相变。
AI 中文摘要
我们基于动力学生成函数，对孤立量子粒子的幺正演化与经典布朗粒子的耗散弛豫过程中的动力学相变给出了统一描述。在半经典与弱噪声极限下，该函数的费舍尔零点在复时间平面内凝聚并抵达对应物理轴，通过返回轨迹间的竞争产生动力学相变。这建立了量子与经典（有限时间）动力学相变间的直接联系，其中半经典极限扮演热力学极限的角色。该联系自然提供了洛施密特振幅的经典版本，并揭示了通常与孤立多体系统相关的动力学量子相变如何在单粒子量子系统中出现。动力学相位由基于轨迹的统一序参量区分，该序参量表现为经典关联函数与序贯量子弱值。
英文摘要
We present a unifying description of dynamical phase transitions in the unitary evolution of an isolated quantum particle and the dissipative relaxation of a classical Brownian particle, based on a dynamical generat- ing function. In the semiclassical and weak-noise limits, Fisher zeros of this function condense in the complex- time plane and reach the corresponding physical axes, producing dynamical phase transitions through a competition between return trajectories. This establishes a direct connection between quantum and classical (finite-time) dynamical phase transitions, where the semiclassical limit plays the role of the thermodynamic limit. In particular, the established link naturally provides a classical version of the Loschmidt amplitude and shows how dynamical quantum phase transitions, typically associated with isolated many-body systems, can arise in a single-particle quantum system. The dynamical phases are distinguished by a unifying, trajectory- based order parameter, realized as a classical correlation function and a sequential quantum weak value.
Comments7 pages, 7 figures
