Many-body enhancement in a spin-chain quantum heat engine

TL;DR

This paper demonstrates that ferromagnetic interactions can significantly enhance the performance of a quantum spin chain heat engine at low temperatures, with effects influenced by entanglement and interaction range.

Contribution

It reveals how ferromagnetic interactions improve quantum engine efficiency and work output, especially in the paramagnetic phase, and proposes a counterdiabatic drive to reduce quantum friction.

Findings

Work output increases exponentially with interaction strength.

Thermal fluctuations reduce performance at higher temperatures.

Long-range interactions lead to higher efficiency due to smaller thermal fluctuations.

Abstract

We show that ferromagnetic interactions can enhance the adiabatic performance of a quantum spin chain engine at low temperatures. The enhancement in work output is particular pronounced, increasing exponentially with interaction strength. The performance enhancement occurs in the paramagnetic phase and is qualitatively explained by considering just the ground and first excited state, in which case the system exhibits bipartite entanglement. As the temperature is increased, thermal occupation of higher energy states diminishes performance. We find that these thermal fluctuations are smallest for long-range interactions, resulting in the highest efficiency. Diabatic work extraction degrades performance due to quantum friction. We identify an approximate, experimentally realisable counterdiabatic drive that can mitigate friction for weak interactions.