论文标题
在非零温度下量子链中的量子相变
Quantum Phase Transition in a Quantum Ising Chain at Nonzero Temperatures
论文作者
论文摘要
我们研究了Ising链的热状态对非局部非热扰动的响应，该扰动在铁磁阶段融合了拓扑Kramer样退化。不同量子相的初始热状态的动态响应是不同的。最终状态总是在铁磁相中以固定的奇偶校验接近其一半成分，但在顺磁相中几乎保持不变。这表明在有限温度下完全保留了零温度下的相图。 Loschmidt的数值模拟在有限大小的系统中显示出这种动力学行为。此外，它在非零温度下提供了散装对应关系的明显表现。这项工作提出了一种理解非零温度下量子自旋系统的量子相变的替代方法。
We study the response of a thermal state of an Ising chain to a nonlocal non-Hermitian perturbation, which coalesces the topological Kramer-like degeneracy in the ferromagnetic phase. The dynamic responses for initial thermal states in different quantum phases are distinct. The final state always approaches its half component with a fixed parity in the ferromagnetic phase but remains almost unchanged in the paramagnetic phase. This indicates that the phase diagram at zero temperature is completely preserved at finite temperatures. Numerical simulations for Loschmidt echoes demonstrate such dynamical behaviors in finite-size systems. In addition, it provides a clear manifestation of the bulk-boundary correspondence at nonzero temperatures. This work presents an alternative approach to understanding the quantum phase transitions of quantum spin systems at nonzero temperatures.
