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arXiv 0909.5181cond-mat.stat-mech
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量子临界点附近的猝灭动力学

Quench dynamics near a quantum critical point

C. De Grandi, V. Gritsev, A. Polkovnikov

摘要:

我们研究了系统在量子临界点开始(或结束)时对调谐参数$λ$的突然改变的动力学响应。特别地,我们分析了激发几率、激发准粒子数、热和熵随猝灭幅度和系统大小的标度。我们扩展的分析淬火与任意幂律依赖于时间的调谐参数,这些数量的标度行为与奇异性的阶$m$在量子临界点,其中$m$是有关的淬火功率之间的密切联系。准确地说,对于突然猝灭,二阶相关磁化率与保真度磁化率相一致。我们讨论了推广的标度律有限温度淬火,并表明,低能量激发的统计变得重要。我们说明这些结果的相关性冷原子实验。

英文摘要:

We study the dynamical response of a system to a sudden change of the tuning parameter $λ$ starting (or ending) at the quantum critical point. In particular we analyze the scaling of the excitation probability, number of excited quasiparticles, heat and entropy with the quench amplitude and the system size. We extend the analysis to quenches with arbitrary power law dependence on time of the tuning parameter, showing a close connection between the scaling behavior of these quantities with the singularities of the adiabatic susceptibilities of order $m$ at the quantum critical point, where $m$ is related to the power of the quench. Precisely for sudden quenches the relevant susceptibility of the second order coincides with the fidelity susceptibility. We discuss the generalization of the scaling laws to the finite temperature quenches and show that the statistics of the low-energy excitations becomes important. We illustrate the relevance of those results for cold atoms experiments.

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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