On the robustness of entanglement in analogue gravity systems

TL;DR

This paper examines how initial temperature affects entanglement generation in analogue gravity systems like Bose-Einstein condensates, providing bounds and mechanisms to preserve quantum correlations amidst thermal noise.

Contribution

It analytically derives an upper temperature bound for entanglement and explores enhancement mechanisms in dispersive, non-zero temperature analogue gravity experiments.

Findings

Entanglement persists below a specific temperature threshold.

A method to enhance quantum correlations against thermal noise.

Robustness of entanglement in quenched Bose-Einstein condensates.

Abstract

We investigate the possibility to generate quantum-correlated quasi-particles utilizing analogue gravity systems. The quantumness of these correlations is a key aspect of analogue gravity effects and their presence allows for a clear separation between classical and quantum analogue gravity effects. However, experiments in analogue systems, such as Bose-Einstein condensates, and shallow water waves, are always conducted at non-ideal conditions, in particular, one is dealing with dispersive media at nonzero temperatures. We analyze the influence of the initial temperature on the entanglement generation in analogue gravity phenomena. We lay out all the necessary steps to calculate the entanglement generated between quasi-particle modes and we analytically derive an upper bound on the maximal temperature at which given modes can still be entangled. We further investigate a mechanism to enhance the quantum correlations. As a particular example we analyze the robustness of the entanglement creation against thermal noise in a sudden quench of an ideally homogeneous Bose-Einstein condensate, taking into account the super-sonic dispersion relations.