# Work statistics for sudden quenches in interacting quantum many-body systems

## TL;DR

This paper introduces a simple method to describe work distribution functions in sudden quenches of quantum many-body systems, using level density and a smoothed strength function, applicable to chaotic and integrable regimes.

## Contribution

It provides a novel, straightforward approach to compute work distributions in large quantum systems based on spectral properties and perturbation effects.

## Key findings

- Accurate description of work distribution in quantum spin chains.
- Effective for intermediate and high temperatures.
- Applicable to both chaotic and integrable regimes.

## Abstract

Work in isolated quantum systems is a random variable and its probability distribution function obeys the celebrated fluctuation theorems of Crooks and Jarzynski. In this study, we provide a simple way to describe the work probability distribution function for sudden quench processes in quantum systems with large Hilbert spaces. This description can be constructed from two elements: the level density of the initial Hamiltonian, and a smoothed strength function that provides information about the influence of the perturbation over the eigenvectors in the quench process, and is especially suited to describe quantum many-body interacting systems. We also show how random models can be used to find such smoothed work probability distribution and apply this approach to different one-dimensional spin-$1/2$ chain models. Our findings provide an accurate description of the work distribution of such systems in the cases of intermediate and high temperatures in both chaotic and integrable regimes.