  The expansion of a harmonic potential that holds a quantum particle may be
realized without any final particle excitation but much faster than
adiabatically via "shortcuts to adiabaticity" (STA). While ideally the process
time can be reduced to zero, practical limitations and constraints impose
minimal finite times for the externally controlled time-dependent frequency
protocols. We examine the role of different time-averaged energies (total,
kinetic, potential, non-adiabatic) and of the instantaneous power in
characterizing or selecting different protocols.Specifically, we prove a virial
theorem for STA processes, set minimal energies for specific times or
viceversa, and discuss their realizability by means of Dirac impulses or
otherwise.
