Unravelling the non-classicality role in Gaussian heat engines

TL;DR

This paper investigates how non-classicality, measured via P-representability, enhances the efficiency of quantum heat engines, demonstrating its role as a fundamental resource in thermodynamic tasks.

Contribution

It introduces a classicality measure based on P-representability to quantify non-classicality and explores its impact on the performance of quantum Otto and generalized heat engine cycles.

Findings

Non-classicality improves work extraction efficiency.

Non-classicality is essential for quantum advantage in heat engines.

Optimal protocols leverage non-classical states for better thermodynamic performance.

Abstract

At the heart of quantum thermodynamics lies a fundamental question about what is genuine "quantum" in quantum heat engines and how to seek this quantumness, so that thermodynamical tasks could be performed more efficiently compared with classical protocols. Here, using the concept of $P$-representability, we define a function called classicality, which quantifies the degree of non-classicality of bosonic modes. This function allows us to explore the role of non-classicality in quantum heat engines and design optimal protocols for work extraction. For two specific cycles, a quantum Otto and a generalised one, we show that non-classicality is a fundamental resource for performing thermodynamic tasks more efficiently.