Detuning-Controlled Phase Transition from Passive to Active Regimes in Non-Markovian Quantum Batteries

TL;DR

This paper explores how detuning and non-Markovian environmental effects can induce a phase transition in a quantum battery, affecting its energy storage and work extraction capabilities.

Contribution

It reveals a phase transition in ergotropy controlled by detuning and coupling, highlighting a new mechanism for optimizing quantum battery performance.

Findings

Environmental memory enhances energy storage and power under certain conditions.

Strong dissipation suppresses ergotropy, leading to passive states.

Detuning induces a phase transition in the extractable work, with a sharp boundary in the phase diagram.

Abstract

We investigate a two-qubit quantum battery where coherent charger-battery coupling competes with non-Markovian environmental interactions. By tuning the coupling strengths and detuning, we identify regimes in which environmental memory enhances energy storage and charging power, while strong dissipation suppresses ergotropy by driving the battery into passive states. We show that detuning plays a dual role: reducing dissipation and inducing a phase shift in the memory kernel that controls the interference between coherent energy exchange and environment-induced backflow. As a result, although the stored energy varies smoothly, the extractable work exhibits a discontinuous onset at a critical detuning, signaling a first-order phase transition in ergotropy. The corresponding phase diagram in the coupling-detuning plane reveals a sharp boundary between thermodynamically inactive and work-producing regimes. Our results demonstrate that phase-controlled coherence and non-Markovianity provide a powerful mechanism for optimizing work extraction in open quantum batteries, offering practical strategies for noise-resilient quantum energy storage.