Entangling two unequal atoms through a common bath

TL;DR

This paper demonstrates that two non-interacting, unequal atoms can become entangled through a common bath using a refined Markovian evolution, surpassing limitations of standard approaches.

Contribution

It introduces a refined Markovian framework that enables entanglement of unequal atoms via a shared environment, which was previously considered impossible.

Findings

Refined dynamics preserve complete positivity.

Unequal atoms can be entangled through a common bath.

Entanglement occurs even with different internal frequencies.

Abstract

The evolution of two, non-interacting two-level atoms immersed in a weakly coupled bath can be described by a refined, time coarse grained Markovian evolution, still preserving complete positivity. We find that this improved reduced dynamics is able to entangle the two atoms even when their internal frequencies are unequal, an effect which appears impossible in the standard weak coupling limit approach. We study in detail this phenomenon for an environment made of quantum fields.