Quantum quenches with long range interactions

TL;DR

This paper extends quantum quench theory to systems with long range interactions, analytically determining post-quench states and explaining persistent oscillations observed numerically.

Contribution

It introduces a method to analyze quantum quenches in long range interacting systems using asymptotic states, providing analytical results for post-quench observables.

Findings

Undamped oscillations persist at large times in long range systems.

Analytical expressions for post-quench states are derived.

The theory explains numerical observations of persistent oscillations.

Abstract

We extend the theory of quantum quenches to the case of $d$-dimensional homogeneous systems with long range interactions. This is achieved treating the long range interactions as switched on by the quench and performing the derivation within the basis of asymptotic states of the short range interacting pre-quench theory. In this way we analytically determine the post-quench state and the one-point functions of local observables such as the order parameter. One implication is that, as in the short range case, some oscillations induced by the quench remain undamped at large times under conditions specified by the theory. This explains, in particular, why such undamped oscillations have been numerically observed also in presence of long range interactions.