Persistent many-body quantum echoes
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 = tau. Subsequently, this state is slightly perturbed and finally propagated for another time period tau 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 tau. Our quantitative analytical predictions compare very well with exact numerical results.
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Amer Physical Soc