论文标题
连贯性的动力学:最大量子渔民信息与洛斯米特回声
Dynamics of coherence: Maximal quantum Fisher information vs. Loschmidt echo
论文作者
论文摘要
我们考虑一维横向场ISING模型的突然淬火后,最大量子渔民信息(MQFI)的动力学。我们的结果表明,与Loschmidt回声相同,复兴时间有一个普遍性,即它们不取决于初始状态和淬火大小,并且由$ t_ {rev} \ simeq \ simeq \ frac \ frac {n}}的Integer倍数给出,$ ns $ n是$ n $ ns $ ns $ ns $ ns $ ns $ ns $ ns $ ns $ v_准颗粒的速度。作为$ t_ {rev} \ equiv t_ {dec} $,在复兴和衰减时间的批判性增强和减少的特征是分别从顺序和混乱阶段淬灭到量子相变到量子相变,可用于检测量子关键点(QCP)。在从QCP越过的一些淬火中,由于识别最大值,由于可观察到的局部观察到从一个方向转移到另一个方向,因此在某些时候出现了非分析行为。我们命名此现象\ textIt {动态MQFI转换},发生在关键时间$ t_c $。有趣的是,尽管在MQFI的动力学中不存在Fisher零,但动态量子相变的第一个关键时间等于第一次,其MQFI的对数最小。此外,我们公布了MQFI的长期运行,表明QCP处的非平衡量子相变的特征。我们还讨论了系统非平衡动力学中宏观叠加产生的可能性。
We consider the dynamics of maximal quantum Fisher information (MQFI) after sudden quenches for the one-dimensional transverse-field Ising model. Our results show, the same as Loschmidt echo, there is a universality for the revival times i.e., they do not depend on the initial state and the size of the quench and are given by integer multiples of $T_{rev} \simeq \frac{N}{2v_{max }}$, where $N$ is the system size and $v_{max }$ is the maximal group velocity of quasiparticles. Critically enhanced and decreased at revival and decay times as $T_{rev} \equiv T_{dec} $ are characterized by quenching from the order and disorder phases into the quantum phase transition respectively, that can be utilized to detect the quantum critical point (QCP). In some quenches crossed from the QCP, nonanalytic behaviors appear at some times due to the turning of the local observable from one direction to another because of identifying the maximum value. We name this phenomenon \textit{the dynamical MQFI transitions}, occurring at the critical times $t_c$. Interestingly, although no Fisher zero exists in the dynamics of MQFI, the first critical time emerged from the dynamical quantum phase transition is equal to the first time whose the logarithm of MQFI is minimum. In addition, we unveil the long-time run of MQFI indicates a signature of a nonequilibrium quantum phase transition at the QCP. We also discuss the probability of arising of macroscopic superpositions in the nonequilibrium dynamics of the system.