  We consider a finite-time Otto engine operating on a quantum harmonic
oscillator and driven by shortcut-to-adiabaticity (STA) techniques to speed up
its cycle. We study its efficiency and power when internal friction,
time-averaged work, and work fluctuations are used as quantitative figures of
merit, showing that time-averaged efficiency and power are useful cost
functions for the characterization of the performance of the engine. We then
use the minimum allowed time for validity of STA protocol relation to establish
a physically relevant bound to the efficiency at maximum power of the
STA-driven cycle.
