Figure 1 (IMAGE) Institute for Basic Science Caption (a) Schematic of a single cycle (Nc =1) of an Otto cycle undergoing four strokes. The working substance is a qubit undergoing imperfect thermalizing heat (heating and cooling) strokes and finite-time work (compression and expansion) strokes. (b) Work output per cycle of the finite-time quantum Otto engine, (c) Reliability of the engine, and (d) The maximum power output. The engine operates for Nc cycles. In all cases, the repeated contacts (RC, blue crosses) scheme that preserves coherence outperforms the repeated measurements (RM, red filled circles) that kill all coherences. Credit Institute for Basic Science Usage Restrictions Attribution Required License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.