Non-equilibrium properties of trapped ions under sudden application of a laser

TL;DR

This paper investigates the non-equilibrium dynamics and irreversibility of a trapped ion subjected to a sudden laser interaction, revealing how nonlinearities and the Lamb-Dicke parameter influence reversibility.

Contribution

It provides a detailed analysis of work statistics and irreversibility in trapped ions beyond the Lamb-Dicke limit, highlighting non-monotonic effects of nonlinearities on reversibility.

Findings

Irreversibility varies non-monotonically with the Lamb-Dicke parameter.

Nonlinearity can enhance reversibility at specific working points.

Analysis extends to multiquantum and sideband regimes.

Abstract

Coherent quantum-state manipulation of trapped ions using classical laser fields is a trademark of modern quantum technologies. In this work, we study aspects of work statistics and irreversibility in a single trapped ion due to sudden interaction with the impinging laser. This is clearly an out-of-equilibrium process where work is performed through illumination of an ion by the laser. Starting with the explicit evaluation of the first moments of the work distribution, we proceed to a careful analysis of irreversibility as quantified by the nonequilibrium lag. The treatment employed here is not restricted to the Lamb-Dicke limit, which allows us to investigate the interplay between nonlinearities and irreversibility. We show that in these multiquantum or sideband regimes, variation of the Lamb-Dicke parameter causes a non-monotonic behavior of the irreversibility indicator. Counterintuitively, we find a working point where nonlinearity helps reversibility, making the sudden quench of the Hamiltonian closer to what would have been obtained quasistatically and isothermally.