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arXiv 2107.02709quant-phcond-mat.quant-gas
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有限尺寸系统中动态量子相变的Loschirm回波零点和量子速度极限时间

Exact zeros of the Loschmidt echo and quantum speed limit time for the dynamical quantum phase transition in finite-size systems

Bozhen Zhou, Yumeng Zeng, Shu Chen

摘要:

本文研究了有限尺寸系统中动态量子相变的Loschirton回波零点和量子速度极限时间。我们的结果表明,即使在有限大小的量子系统中,当后猝灭参数在相应的平衡相位与初始相位不同的区域中取某些离散值时,也存在精确的Loschirton回波零点。随着系统规模的增大并趋于无穷大,离散参数在参数区域内连续分布。我们进一步分析了Loschirt回波第一个精确零点出现的时间,即量子速度极限时间$τ_{\text{QSL}}$。我们证明了当我们将初始非临界态猝灭到临界相时,$τ_{\text{QSL}}$的最大值与$L$成正比,并在临界极限处趋于无穷大.我们还计算了$τ_{\text{QSL}}$的极小值,发现它的行为依赖于初态的相位。

英文摘要:

We study exact zeros of Loschmidt echo and quantum speed limit time for dynamical quantum phase transition in finite size systems. Our results illustrate that exact zeros of Loschmidt echo exist even in finite size quantum systems when the postquench parameter takes some discrete values in regions with the corresponding equilibrium phase different from the initial phase. As the system size increases and tends to infinity, the discrete parameters distribute continuously in the parameter regions. We further analyze the time for the appearance of the first exact zero of Loschmidt echo which is known as the quantum speed limit time $τ_{\text{QSL}}$. We demonstrate that the maximal value of $τ_{\text{QSL}}$ is proportional to $L$ and approaches infinity in the thermodynamical limit, when we quench the initial non-critical state to the critical phase. We also calculate the minimal value of $τ_{\text{QSL}}$ and find that its behavior is dependent on the phase of initial state.

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。

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