A many-body heat engine at criticality

TL;DR

This paper demonstrates that a quantum Otto cycle using an ultracold gas near a phase transition can outperform single-particle engines, with optimized protocols mitigating non-equilibrium effects.

Contribution

It introduces a many-body quantum heat engine leveraging phase transitions and develops a shortcut to adiabaticity for efficient operation.

Findings

Many-body effects enhance engine performance.

Energy gap improves efficiency.

Shortcut protocols reduce non-equilibrium losses.

Abstract

We show that a quantum Otto cycle in which the medium, an interacting ultracold gas, is driven between a superfluid and an insulating phase can outperform similar single particle cycles. The presence of an energy gap between the two phases can be used to improve performance, while the interplay between lattice forces and the particle distribution can lead to a many-body cooperative effect. Since finite time driving of this cycle can create unwanted non-equilibrium dynamics which can significantly impair the performance of the engine cycle, we also design an approximate shortcut to adiabaticity for the many-body state that can be used to achieve an efficient Otto cycle around a critical point.