Quenching, Fast and Slow: Breaking Kibble-Zurek Universal Scaling by Jumping along Geodesics

Abstract

A major drawback of adiabatic quantum computing (AQC) is fulfilling the energy gap constraint, which requires the total evolution time to scale inversely with the square of the minimum energy gap. Failure to satisfy this condition violates the adiabatic approximation, potentially undermining computational accuracy. Recently, several approaches have been proposed to circumvent this constraint. One promising approach is to use the family of adiabatic shortcut procedures to fast-forward AQC. One caveat, however, is that it requires an additional Hamiltonian that is very challenging to implement experimentally. Here, we investigate an alternate pathway that avoids any extra Hamiltonian in the evolution to fast-forward the adiabatic dynamics by traversing geodesics of a quantum system. We find that jumping along geodesics offers a striking mechanism to highly suppress the density of excitations in many-body systems. Particularly, for the spin-$1/2$ XY model, we analytically prove and numerically demonstrate a rate-independent defect plateau, which contrasts with well-established results for the Kibble-Zurek and anti-Kibble-Zurek mechanisms.