Entanglement Generation is Not Necessary for Optimal Work Extraction

TL;DR

This paper demonstrates that optimal work extraction from quantum batteries can be achieved without entanglement, challenging the notion that entanglement is necessary for maximum work output, and explores the trade-offs involved.

Contribution

It introduces a method to extract all work without creating entanglement, and analyzes the relationship between entanglement and extraction speed.

Findings

Work can be extracted without entanglement but requires more operations.

A quantitative relation between entanglement and extractable work is established.

Faster work extraction methods are studied with entanglement considerations.

Abstract

We consider reversible work extraction from identical quantum batteries. From an ensemble of individually passive states, work can be produced only via global unitary (and thus entangling) operations. However, we show here that there always exists a method to extract all possible work without creating any entanglement, at the price of generically requiring more operations (i.e. additional time). We then study faster methods to extract work and provide a quantitative relation between the amount of generated multipartite entanglement and extractable work. Our results suggest a general relation between entanglement generation and the power of work extraction.