Bounds on fluctuations for finite-time quantum Otto cycle

For finite-time quantum Otto heat engine with working fluid consisting of either a (i) qubit or (ii) harmonic oscillator, we show that the relative fluctuation output work is always greater than corresponding input absorbed from hot bath. As result, ratio between and receives lower bound in terms square value average efficiency engine. The saturation received quasi-static limit can be shown for class fluids follow scale-invariant energy eigenspectra under driving.