# Macroscopic realism of quantum work fluctuations

## TL;DR

This paper investigates the differences between quantum and classical work fluctuations in driven quantum systems, demonstrating that quantum fluctuations violate macrorealistic Leggett-Garg inequalities, unlike classical ones.

## Contribution

It introduces a method to distinguish quantum from classical work fluctuations using Leggett-Garg inequalities and shows their violation in specific quantum systems.

## Key findings

- Quantum work fluctuations violate Leggett-Garg inequalities.
- Classical work fluctuations obey macrorealistic theories.
- Violations observed in two-level systems and squeezed oscillators.

## Abstract

We study the fluctuations of the work performed on a driven quantum system, defined as the difference between subsequent measurements of energy eigenvalues. These work fluctuations are governed by statistical theorems with similar expressions in classical and quantum physics. In this article we show that we can distinguish quantum and classical work fluctuations, as the latter can be described by a macrorealistic theory and hence obey Leggett-Garg inequalities. We show that these inequalities are violated by quantum processes in a driven two-level system and in a harmonic oscillator subject to a squeezing transformation.