Noisy propagation of Gaussian states in optical media with finite bandwidth

TL;DR

This paper investigates how Gaussian quantum states propagate and entangle in optical media with finite bandwidth, revealing conditions under which decoherence is minimized and entanglement can be preserved.

Contribution

It introduces a model for Gaussian state propagation in finite bandwidth environments, highlighting regimes that protect entanglement from decoherence.

Findings

Attenuation is suppressed at low temperatures.

Diffusion depends only on the bandwidth.

Certain regimes allow entanglement preservation.

Abstract

We address propagation and entanglement of Gaussian states in optical media characterised by non-trivial spectral densities. In particular, we consider environments with a finite bandwidth and show that in the low temperature regime: i) secular terms in the master equation may be neglected; ii) attenuation (damping) is strongly suppressed; iii) the overall diffusion process may be described as a Gaussian noise channel with variance depending only on the bandwidth. We find several regimes where propagation is not much detrimental and entanglement may be protected form decoherence.