Annulled van der Waals interaction and fast Rydberg quantum gates

A pair of neutral atoms separated by several microns and prepared in identical s states of large principal quantum number experience a van der Waals interaction. If microwave fields are used to generate a superposition of s states with different principal quantum numbers, a null point may be found at which a specific superposition state experiences no van der Waals interaction. An application of this Rydberg state in a quantum controlled-z gate is proposed, which takes advantage of GHz rate transitions to nearby Rydberg states. A gate operation time in the tens of nanoseconds is predicted.