Optimal energy conversion through antiadiabatic driving breaking time-reversal symmetry

Starting with the Carnot engine, the ideal efficiency of a heat engine has been associated with quasistatic transformations and vanishingly small output power. Here, we exactly calculate the thermodynamic properties of an isothermal heat engine, in which the working medium is a periodically driven underdamped harmonic oscillator, focusing instead on the opposite, antiadiabatic limit, where the period of a cycle is much shorter than the system's timescales. We show that in that limit it is possible to approach the ideal energy conversion efficiency η=1, with finite output power and vanishingly small relative power fluctuations. The simultaneous realization of all the three desiderata of a heat engine is possible thanks to the breaking of time-reversal symmetry. We also show that non-Markovian dynamics can further improve the power-efficiency trade-off.