Shortcuts to adiabaticity designed via time-rescaling follow the same transitionless route

Abstract: 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.