Charging of a Quantum Battery by a Single-Photon Quantum Pulse

TL;DR

This paper models the process of charging a quantum battery using a single-photon pulse, deriving optimal conditions and fundamental limits for energy transfer, speed, and power in a minimal quantum system.

Contribution

It provides analytical solutions for the dynamics of a quantum battery charged by a single-photon pulse, including optimal pulse shaping and quantum speed limits.

Findings

Optimal pulse shape saturates universal energy bound

Derived minimum charging time and quantum speed limit

Analytical expressions for charging power and pulse duration

Abstract

We study a minimal model for charging a quantum battery consisting of a two-level system (TLS) acting as a charger, coupled to a harmonic oscillator that serves as the quantum battery. A single-photon quantum pulse of light excites the TLS, which subsequently transfers its excitation to the isolated battery. The TLS may also decay into the electromagnetic environment. We obtain analytical solutions for the dynamics of the battery and determine the optimal pulse shape that maximizes the stored energy. The optimal pulse saturates a universal bound for the stored energy, determined by the TLS decay rates into the pulse and the environment. Furthermore, we derive the minimum charging time and establish a quantum speed limit at the exceptional point, where a critical transition occurs in the system's dynamics. We also present analytical expressions for the charging power and investigate the pulse duration that maximizes it.