Minimum-Time Control of Local Quantum Gates for Two-Qubit Homonuclear Systems

This paper presents a design method for minimum-time control of homonuclear spin systems. We firstly estimate the minimum time based on a multiple time-scale analysis, following which an improved gradient algorithm is deigned to search the control profile. Numerical simulations show that this method can effectively reduce the search efforts for finding the minimum-time control for two-spin systems.