Abstract Fast quasi-adiabatic driving (FAQUAD) is a central technique in shortcuts to adiabaticity (STA), enabling accelerated adiabatic evolution by optimizing the rate of change of a single control parameter. However, many realistic systems are governed by multiple coupled parameters, where the adiabatic condition depends not only on the local rate of change but also on the path through parameter space. Here, we employ an enhanced FAQUAD framework that incorporates path optimization in addition to conventional velocity optimization, extending it to two-dimensional parameter spaces supporting band gaps, where rapid parameter variations inevitably trigger nonadiabatic transitions. To demonstrate the true power of STA in restoring adiabaticity against these transitions, we use a coupled elastic-waveguide system, where the synthetic parameters–detuning and coupling–are controlled by the thicknesses of the waveguides and connecting bridges. Using scanning laser Doppler vibrometry, we directly map the flexural-wave field and observe the restored adiabatic energy transfer along the optimized path throughout the process. This elastic-wave platform provides a versatile classical analogue for exploring multidimensional adiabatic control, demonstrating efficient and compact implementation of shortcut-to-adiabaticity protocols.
Liu et al. (Wed,) studied this question.