Non-Markovian entanglement dynamics of noisy continuous variable quantum channels

TL;DR

This paper studies how non-Markovian environments affect the entanglement dynamics of continuous-variable quantum channels, revealing environment-dependent effects on decoherence and entanglement preservation.

Contribution

It derives an exact non-Markovian master equation for continuous-variable systems and analyzes the impact of different spectral densities on entanglement evolution.

Findings

Ohmic environment causes weak dissipation and noise effects

Sub-Ohmic and super-Ohmic environments induce stronger noise

Memory effects in super-Ohmic environments lead to significant decoherence

Abstract

We investigate the entanglement dynamics of continuous-variable quantum channels in terms of an entangled squeezed state of two cavity fields in a general non-Markovian environment. Using the Feynman-Vernon influence functional theory in the coherent-state representation, we derive an exact master equation with time-dependent coefficients reflecting the non-Markovian influence of the environment. The influence of environments with different spectral densities, e.g., Ohmic, sub-Ohmic, and super-Ohmic, is numerically studied. The non-Markovian process shows its remarkable influences on the entanglement dynamics due to the sensitive time-dependence of the dissipation and noise functions within the typical time scale of the environment. The Ohmic environment shows a weak dissipation-noise effect on the entanglement dynamics, while the sub-Ohmic and super-Ohmic environments induce much more severe noise. In particular, the memory of the system interacting with the environment contributes a strong decoherence effect to the entanglement dynamics in the super-Ohmic case.