Quantum correlations in dissipative gain-loss systems across exceptional points

TL;DR

This paper explores how quantum correlations behave in a dissipative gain-loss system, revealing effects of PT symmetry and exceptional points on correlation dynamics, with implications for realistic quantum systems.

Contribution

It introduces a realistic gain-loss model with local gain, analyzing correlation dynamics across exceptional points and highlighting PT symmetry's influence at large times.

Findings

Quantum correlations are reduced in the gain-loss system.

Total correlations are enhanced despite dissipation.

Different behaviors across exceptional points occur mainly in transient dynamics.

Abstract

We investigate the behavior of correlations dynamics in a dissipative gain-loss system. First, we consider a setup made of two coupled lossy oscillators, with one of them subject to a local gain. This provides a more realistic platform to implement parity-time (PT) symmetry circumventing the implementation of a pure gain. We show how the qualitative dynamics of correlations resembles that for a pure-gain-loss setup. The major quantitative effect is that quantum correlations are reduced, while total ones are enhanced. Second, we study the behavior of these correlations across an exceptional point (EP) outside of the PT-symmetric regime of parameters, observing how different behaviors across the EP occur only in the transient dynamics. This shows how PT symmetry plays a relevant role at large times.