论文标题
持续的多体量子回声
Persistent many-body quantum echoes
论文作者
论文摘要
我们考虑量子多体系统在与时间无关的哈密顿$ h $下进化，从时间上的非平衡初始状态$ t = 0 $ to $ t = 0 $ $ t =τ$。随后，在倒置的汉密尔顿$ -H $下，该状态略有干扰，最后在另一个时期$τ$传播。整个过程也可以看作是不完美的时间反转或“回声动力学”。我们揭示了这种动力学的显着持久性，就时间依赖性期望值与平衡期望值的可观察到的偏差：对于大多数扰动而言，最终状态的偏差本质上与反转时间点$τ$相关。我们的定量分析预测与精确的数值结果相比。
We consider quantum many-body systems evolving under a time-independent Hamiltonian $H$ from a nonequilibrium initial state at time $t=0$ towards a close-to-equilibrium state at time $t=τ$. Subsequently, this state is slightly perturbed and finally propagated for another time period $τ$ under the inverted Hamiltonian $-H$. The entire procedure may also be viewed as an imperfect time inversion or "echo dynamics". We unravel a remarkable persistence of such dynamics with respect to the observable deviations of the time-dependent expectation values from the equilibrium expectation value: For most perturbations, the deviations in the final state are essentially independent of the inversion time point $τ$. Our quantitative analytical predictions compare very well with exact numerical results.
