Suppression of entanglement in two-mode Gaussian open systems

TL;DR

This paper investigates how entanglement between two bosonic modes evolves in a thermal environment, showing that finite temperature causes entanglement to vanish after a finite time, while zero temperature preserves it indefinitely.

Contribution

It provides a detailed analysis of entanglement decay in Gaussian states within open quantum systems, including explicit calculations of survival times at finite temperatures.

Findings

Entanglement always becomes separable at finite temperature.

At zero temperature, entanglement persists indefinitely but eventually vanishes asymptotically.

The survival time depends on temperature, squeezing, and thermal photon numbers.

Abstract

We study the evolution of the entanglement of two independent bosonic modes embedded in a thermal environment, in the framework of the theory of open quantum systems. As a measure of entanglement we use the logarithmic negativity. For a non-zero temperature of the thermal reservoir the entangled initial Gaussian states become always separable in a finite time. For initial squeezed thermal states we calculate the survival time of entanglement and analyze its dependence on temperature, squeezing parameter and mean thermal photon numbers. For a zero temperature of the thermal bath an entangled initial state remains entangled for all finite times, but in the limit of asymptotically large times it becomes separable.