Using a quantum SWAP engine to experimentally validate thermodynamic uncertainty relations

TL;DR

This paper experimentally validates thermodynamic uncertainty relations using a quantum SWAP engine implemented on an NMR setup, demonstrating TUR compliance and violations in different operational regimes.

Contribution

It introduces an experimental quantum SWAP engine setup to test and validate different thermodynamic uncertainty relations in quantum thermodynamics.

Findings

Generalized TUR is obeyed in all regimes.

Tighter TUR is violated in some regimes.

Quantum SWAP engine can function as heat engine and refrigerator.

Abstract

Thermodynamic uncertainty relations (TURs) arise from the bounds on fluctuations of thermodynamics quantities during a non-equilibrium process and they impose constraints on the corresponding process. We experimentally implement a quantum SWAP engine on a nuclear magnetic resonance setup and demonstrate that a Gibbs thermal state can be prepared in two different ways, either directly from a thermal equilibrium state, or by first initializing the system in a pseudopure state. We show that the quantum SWAP engine can work both as a heat engine and as a refrigerator. Starting from a pseudopure state, we construct the SWAP engine, and investigate the violation of two different TURs, namely a generalized TUR and a tighter, more specific TUR. Our results validate that the generalized TUR is obeyed in all the working regimes of the SWAP engine, while the tighter TUR is violated in certain regimes. ~