Quantum quenches from integrability: the fermionic pairing model

TL;DR

This paper demonstrates that integrability-based nonperturbative methods can fully characterize quantum quenches in interacting fermionic systems, revealing universal features relevant to atomic physics and condensed matter.

Contribution

It introduces a nonperturbative approach using integrability to analyze quantum quenches in the fermionic pairing model, advancing understanding of non-equilibrium dynamics.

Findings

Complete characterization of quantum quenches in Richardson's model.

Identification of universal features in quench dynamics.

Analysis of effects of multiple quenches on observables.

Abstract

Understanding the non-equilibrium dynamics of extended quantum systems after the trigger of a sudden, global perturbation (quench) represents a daunting challenge, especially in the presence of interactions. The main difficulties stem from both the vanishing time scale of the quench event, which can thus create arbitrarily high energy modes, and its non-local nature, which curtails the utility of local excitation bases. We here show that nonperturbative methods based on integrability can prove sufficiently powerful to completely characterize quantum quenches: we illustrate this using a model of fermions with pairing interactions (Richardson's model). The effects of simple (and multiple) quenches on the dynamics of various important observables are discussed. Many of the features we find are expected to be universal to all kinds of quench situations in atomic physics and condensed matter.