Entanglement Generation is Not Necessary for Optimal Work Extraction

Understand

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).