论文标题
在开放量子多体系统的非稳态模式下自发对称性破裂
Spontaneous symmetry breaking in non-steady modes of open quantum many-body systems
论文作者
论文摘要
在耦合到环境的量子多体系统中，当控制参数超过临界值时，其稳态可以表现出自发的对称性破坏。在这项研究中，我们考虑在开放量子多体系统的非稳态模式下自发对称性破裂。假设系统的密度矩阵的时间演变由马尔可夫主方程描述，则系统的动力学以相应的时间演化超级启动器的特征码和光谱充分表征。在具有有限寿命的非态征本的特征模中，我们专注于频率最高的本征模，我们称之为最连贯的模式。对于耗散旋转模型，最连贯的模式表明，即使稳定状态没有显示出奇异的行为，也表现出从无序阶段到对称性断断续续的有序相的过渡。我们进一步认为，最连贯的模式的相变会引起高度纠缠状态（即Schrödinger的猫态）的逆转动力学的质量变化。
In a quantum many-body system coupled to the environment, its steady state can exhibit spontaneous symmetry breaking when a control parameter exceeds a critical value. In this study, we consider spontaneous symmetry breaking in non-steady modes of an open quantum many-body system. Assuming that the time evolution of the density matrix of the system is described by a Markovian master equation, the dynamics of the system is fully characterized by the eigenmodes and spectrum of the corresponding time evolution superoperator. Among the non-steady eigenmodes with finite lifetimes, we focus on the eigenmodes with the highest frequency, which we call the most coherent mode. For a dissipative spin model, it is shown that the most coherent mode exhibits a transition from a disordered phase to a symmetry-broken ordered phase, even if the steady state does not show singular behavior. We further argue that the phase transition of the most coherent mode induces a qualitative change in the decoherence dynamics of highly entangled states, i.e., the Schrödinger's cat states.
