论文标题
具有远距离相互作用的骨气系统中的动力量子相变
Dynamical quantum phase transition in a bosonic system with long-range interactions
论文作者
论文摘要
在本文中，我们研究了Loschmidt Echo中出现的动态量子相变，以及与远程相互作用的powerlaw decay $σ$的函数的谐波耦合退化玻色子的量子系统的时间相关顺序参数。突然淬火后，该系统的非平衡动力学由一组非线性耦合的Ermakov方程控制。为了解决它们，我们开发出在后期有效的分析近似。基于此近似值，我们表明，动态量子相变的出现在淬灭之后从无质量初始状态开始，这取决于有限的质量间隙的产生。通常，我们可以定义两个不同的动态阶段，这些动力阶段的特征是淬火后质量间隙的有限性。每当初始状态具有消失的质量间隙并且最终状态具有有限的质量间隙时，Loschmidt Echo就会表现出定期的非分析尖端。这些尖尖显示与时间依赖性的远程相关性的最大值相吻合。
In this paper, we investigate the dynamical quantum phase transitions appearing in the Loschmidt echo and the time-dependent order parameter of a quantum system of harmonically coupled degenerate bosons as a function of the power-law decay $σ$ of long-range interactions. Following a sudden quench, the nonequilibrium dynamics of this system are governed by a set of nonlinear coupled Ermakov equations. To solve them, we develop an analytical approximation valid at late times. Based on this approximation, we show that the emergence of a dynamical quantum phase transition hinges on the generation of a finite mass gap following the quench, starting from a massless initial state. In general, we can define two distinct dynamical phases characterized by the finiteness of the post-quench mass gap. The Loschmidt echo exhibits periodical nonanalytic cusps whenever the initial state has a vanishing mass gap and the final state has a finite mass gap. These cusps are shown to coincide with the maxima of the time-dependent long-range correlations.
