Geometric Landau-Zener-Stückelberg-Majorana interferometry for hybrid spin registers

Abstract

Hybrid systems of electron and nuclear spins are a fundamental building block for scalable quantum information processing. Here we propose a fast and high-fidelity control scheme based on geometric Landau-Zener-St\"uckelberg-Majorana interferometry, using a nitrogen-vacancy center in diamond as an example. When this hybrid spin multilevel system is driven through avoided crossings, geometric phases accumulate in each spin subspace and manifest as interference patterns in the dynamics of the whole system. We systematically study the effects of various decoherence mechanisms and fluctuations of control parameters on this geometric phase process. We also consider the application of quantum memory, where electron spins are used as a processing qubit and nuclear spins are used as a storage qubit. This scheme can achieve a transfer fidelity of 0.985 and a total storage fidelity of 0.96. These results pave the way for geometric coherent manipulations on a variety of hybrid quantum platforms.