arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2103.15340quant-phcond-mat.mes-hallcond-mat.quant-gas
收藏

Uhlmann过程中自旋- $j$体系的低温拓扑相变:一般形式和实验方案

Finite-temperature topological phase transitions of spin-$j$ systems in Uhlmann processes: General formalism and experimental protocols

Xu-Yang Hou, Hao Guo, Chih-Chun Chien

摘要:

乌尔曼过程建立在混合量子态的密度矩阵上,并提供了一种在有限温度下表征拓扑性质的方法。本文分析了在磁场中经历Uhlmann过程的理想自旋-j量子顺磁体,导出了当系统在参数空间中绕一个大圆运动时,任意j的Uhlmann相位和Loschlmann振幅的一般公式。一个量子化的Uhlmann相位的跳跃表示拓扑量子相变(TQPT)的基础过程,这是伴随着零的洛施图振幅。对j=1/2和j=1系统的精确结果表明,系统的拓扑结构只在有限温度下存在,而在零温度下不存在,TQPT的个数与参数空间中的绕组数有关.我们的研究结果铺平了道路,未来的研究有限温度的拓扑性质,可能的实验协议和原子模拟器和数字模拟的影响进行了讨论。

英文摘要:

The Uhlmann process is built on the density matrix of a mixed quantum state and offers a way to characterize topological properties at finite temperatures. We analyze an ideal spin-j quantum paramagnet in a magnetic field undergoing an Uhlmann process and derive general formulae of the Uhlmann phase and Loschmidt amplitude for arbitrary j as the system traverses a great circle in the parameter space. A quantized jump of the Uhlmann phase signifies a topological quantum phase transition (TQPT) of the underlying process, which is accompanied by a zero of the Loschmidt amplitude. The exact results of j=1/2 and j=1 systems show topological regimes that only survive at finite temperatures but not at zero temperature, and the number of TQPTs is associated with the winding number in the parameter space. Our results pave the way for future studies on finite-temperature topological properties, and possible experimental protocols and implications for atomic simulators and digital simulations are discussed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑