  Time-rescaling (TR) has been recently proposed as a method to engineer fast
processes, also known as shortcuts to adiabaticity (STA), which enables the
coherent control of quantum systems beyond the adiabatic regime [B. L.
Bernardo, Phys. Rev. Res. 2, 013133 (2020)]. The method provides the
Hamiltonians that generate the fast processes without requiring information
about the instantaneous eigenstates of a reference protocol, whereas
experimental implementations dismiss additional coupling fields when compared
with adiabatic protocols. Here, we revisit the technique and show that the
obtained fast dynamics are transitionless, similar to the ones designed via the
famous counterdiabatic (CD) approach. We also show that the time evolution of
the STA found via TR relates to that of the reference adiabatic protocol by a
simple reparametrization of time. To illustrate our findings, we studied the
problem of speeding up the stimulated Raman adiabatic passage (STIRAP) and
found out that TR revealed quantum dynamics more robust to parameter variations
than those provided by the CD technique. Our results shed new light on the
application of TR in the control of larger quantum systems.
