Entanglement generation in quantum thermal machines

TL;DR

This paper demonstrates that in linear quantum thermal machines, entanglement between reservoir modes is inevitably generated at low temperatures due to energy conversion from the driving field, linking quantum correlations to thermodynamic principles.

Contribution

It reveals the fundamental process of entanglement generation in driven quantum systems coupled to thermal reservoirs, connecting quantum entanglement with the third law of thermodynamics.

Findings

Entanglement occurs between reservoir modes with frequencies summing to the drive frequency.

Entanglement persists at temperatures higher than those achievable with sideband cooling.

The process is driven by the transformation of the driving energy into pairs of excitations in the reservoirs.

Abstract

We show that in a linear quantum machine, a driven quantum system that evolves while coupled with thermal reservoirs, entanglement between the reservoir modes is unavoidably generated. This phenomenon, which occurs at sufficiently low temperatures and is at the heart of the third law of thermodynamics, is a consequence of a simple process: the transformation of the energy of the driving field into pairs of excitations in the reservoirs. For a driving with frequency $\omega_{d}$ we show entanglement exists between environmental modes whose frequencies satisfy the condition $\omega_{i} + \omega_{j}= \omega_{d}$. We show that this entanglement can persist for temperatures that can be significantly higher than the lowest achievable ones with sideband resolved cooling methods.