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arXiv 1902.01567cond-mat.quant-gascond-mat.stat-mech
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含时陷阱费米气体中量子功统计和Loscherton回波的粒子数标度

Particle-number scaling of the quantum work statistics and Loschmidt echo in Fermi gases with time-dependent traps

Ettore Vicari

摘要:

我们研究了d维费米气体在稀态下的非平衡动力学的某些特性与粒子数的关系。我们认为协议需要变化的外部电位,限制在一个有限的空间区域内的颗粒,特别是突然变化的陷阱大小。为了表征费米气体的动力学行为,我们考虑了各种全局量,如不同陷阱大小的基态保真度,与所考虑的协议相关联的量子工作统计,以及测量初始基态与平衡态量子态重叠的Loscherton回波。它们的渐近粒子数依赖性显示非相互作用费米气体的幂律。我们还讨论了短程相互作用的平均功的幂律及其平方起伏的影响,在哈伯德模型和它的连续极限,认为他们一般不改变自由费米气体的粒子数幂律,在任何空间维度。

英文摘要:

We investigate the particle-number dependence of some features of the out-of-equilibrium dynamics of d-dimensional Fermi gases in the dilute regime. We consider protocols entailing the variation of the external potential which confines the particles within a limited spatial region, in particular sudden changes of the trap size. In order to characterize the dynamic behavior of the Fermi gas, we consider various global quantities such as the ground-state fidelity for different trap sizes, the quantum work statistics associated with the protocol considered, and the Loschmidt echo measuring the overlap of the out-of-equilibrium quantum states with the initial ground state. Their asymptotic particle-number dependences show power laws for noninteracting Fermi gases. We also discuss the effects of short-ranged interactions to the power laws of the average work and its square fluctuations, within the Hubbard model and its continuum limit, arguing that they do not generally change the particle-number power laws of the free Fermi gases, in any spatial dimensions.

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