Quantum phase transitions are central to our understanding of why matter at very low temperatures can exhibit starkly different properties upon small changes of microscopic parameters. Accurately locating those transitions is challenging experimentally and theoretically. Here, we show that the antithetic strategy of forcing systems out of equilibrium via sudden quenches provides a route to locate quantum phase transitions. Specifically, we show that such transitions imprint distinctive features in the intermediate-time dynamics, and results after equilibration, of local observables in quantum chaotic spin chains. Furthermore, we show that the effective temperature in the expected thermal-like states after equilibration can exhibit minima in the vicinity of the quantum critical points. We discuss how to test our results in experiments with Rydberg atoms and explore nonequilibrium signatures of quantum critical points in models with topological transitions.

中文翻译：

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量子混沌一维系统中淬灭后的量子相变特征

量子相变对于我们理解为什么物质在极低温度下会在微观参数发生微小变化时表现出截然不同的性质至关重要。准确定位这些转变在实验和理论上都具有挑战性。在这里，我们展示了通过突然猝灭迫使系统脱离平衡的对立策略提供了一种定位量子相变的途径。具体来说，我们表明这种转变在量子混沌自旋链中的局部可观察量的中间时间动力学和平衡后的结果中留下了独特的特征。此外，我们表明平衡后预期的类热状态中的有效温度可以在量子临界点附近表现出最小值。