Universal Single-Frequency Oscillations in a Quantum Impurity System After a Local Quench

TL;DR

This paper predicts and demonstrates the emergence of long-lived, single-frequency oscillations in the non-equilibrium dynamics of a quantum impurity system after a local quench, revealing a novel universal behavior.

Contribution

It introduces the concept of quench-independent oscillations in quantum impurity systems and shows their manifestation in entanglement spectra and local observables.

Findings

Oscillations characterized by a single frequency emerge after a local quench.

The frequency is independent of the energy released and scales with inverse system size.

Local observables like spin-spin correlations also exhibit these oscillations.

Abstract

Long-lived single-frequency oscillations in the local non-equilibrium dynamics of a quantum many-body system is an exceptional phenomenon. In fact, till now, it has never been observed, nor predicted, for the physically relevant case where a system is prepared to be quenched from one quantum phase to another. Here we show how the quench dynamics of the entanglement spectrum may reveal the emergence of such oscillations in a correlated quantum system with Kondo impurities. The oscillations we find are characterized by a single frequency. This frequency is independent of the amount of energy released by the local quench, and scales with the inverse system size. Importantly, the quench-independent frequency manifests itself also in local observables, such as the spin-spin correlation function of the impurities.