论文标题

基于量子kibble-zurek机制的干涉法

Interferometry based on quantum Kibble-Zurek mechanism

论文作者

Kou, Han-Chuan, Li, Peng

论文摘要

我们通过举例说明两个原型淬灭协议,即往返和四分之一扭转的方案,在量子千泽机构的框架内提出了一个干涉法。每个协议都包含两个线性坡道,这些坡道将系统跨越量子临界点两次。这两个线性坡道引起了两个各自的非绝热临界动力学,这些动力学由量子kibble-zurek机制很好地描述。但是,结合使用,两个关键动态可以彼此深入干扰。作为干扰的效果,动态阶段在最终激发概率中暴露出来,这导致量子相干多体振荡在具有可预测的特征周期的缺陷密度中。因此,这种干扰可用于直接实验观察。在量子$ xy $模型中,我们表明,干扰也可能是由从临界点和三个临界点得出的两个不同的临界动力学之间的相互作用引起的。此外,我们证明了干扰通过在缺陷 - 缺失缺失相关器中披露多个长度尺度,对角线和偏对基因的现象,从而影响了激发准粒子模式的脱落。事实证明,基于偏斜的结果依赖于对角线和非对角线长度如何由淬灭协议中的可控参数调节。

We propose an interferometry within the framework of quantum Kibble-Zurek mechanism by exemplifying two prototypical quench protocols, namely the round-trip and quarter-turn ones, on the transverse Ising and quantum $XY$ chains. Each protocol contains two linear ramps that drive the system across quantum critical point twice. The two linear ramps arouse two respective nonadiabatic critical dynamics that are well described by the quantum Kibble-Zurek mechanism. However, in combination, the two critical dynamics can interfere with each other deeply. As an effect of the interference, the dynamical phase is exposed in the final excitation probability, which leads to a quantum coherent many-body oscillation in the density of defects with predictable characteristic period. Thus such an interference is available for direct experimental observations. In the quantum $XY$ model, we show that an interference can also arise from the interplay between two different critical dynamics derived from a critical point and a tricritical point. Furthermore, we demonstrate that the interference influences the dephasing of the excited quasiparticle modes intricately by disclosing a phenomenon of multiple length scales, diagonal and off-diagonal ones, in the defect-defect correlators. It turns out that the dephased result relies on how the diagonal and off-diagonal lengths are modulated by the controllable parameter in a quench protocol.

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