Quantum engines that run on measurement instead of heat

A qubit engine powered by quantum measurements instead of a hot thermal bath can extract more work than a standard quantum Otto cycle, provided the measurements are chosen from a broader class (POVMs) rather than simple projections. Counterintuitively, running the engine at finite speed — not the slow adiabatic limit — can also boost both work output and efficiency. The results give concrete design rules for lab-scale quantum engines where controllable measurements replace hard-to-engineer heat reservoirs.