Environment induced entanglement in a refined weak-coupling limit

TL;DR

This paper demonstrates that environment-induced entanglement between two non-interacting qubits can occur even with different frequencies when using a refined weak-coupling approach that goes beyond the standard ergodic average approximation.

Contribution

The authors develop a refined weak-coupling framework that captures environment-induced entanglement for qubits with different frequencies, overcoming limitations of the standard approach.

Findings

Entanglement persists for different qubit frequencies in the refined model.

Standard weak-coupling limit fails to predict entanglement for different frequencies.

Refined approach captures dissipative effects missed by the standard method.

Abstract

Two non-directly interacting qubits with equal frequencies can become entangled via a Markovian, dissipative dynamics through the action of a weakly coupled Ohmic heat bath. In the standard weak-coupling limit derivation, this purely dissipative effect disappears if the frequencies are different because of the "ergodic average" used by this approach. However, there are physical situations where this technique is too rough to capture all the relevant aspects of the dissipative dynamics. In these cases, in order to better describe the physical behavior of the open system, it is necessary to go beyond the "ergodic average". We show that, in this more refined framework, the entanglement capability of the environment persists also in the case of different frequencies.