Improved indirect control of nuclear spins in diamond NV centers

TL;DR

This paper demonstrates a universal indirect control scheme for nuclear spins in diamond NV centers using microwave pulses on electron spins, enabling efficient quantum operations without radio-frequency pulses across various conditions.

Contribution

It introduces a novel indirect control method for nuclear spins in NV centers using microwave-driven electron spins, avoiding radio-frequency pulses and applicable over diverse magnetic fields and temperatures.

Findings

Achieved universal control of nuclear spins via microwave pulses.

Enabled nuclear spin polarization and measurement without RF pulses.

Applicable across a wide range of magnetic fields and temperatures.

Abstract

Hybrid quantum registers consisting of different types of qubits offer a range of advantages as well as challenges. The main challenge is that some types of qubits react only slowly to external control fields, thus considerably slowing down the information processing operations. One promising approach that has been tested in a number of cases is to use indirect control, where external fields are applied only to qubits that interact strongly with resonant excitation pulses. Here we use this approach to indirectly control the nuclear spins of an NV center, using microwave pulses to drive the electron spin, combined with free precession periods optimized for generating logical gate operations on the nuclear spins. The scheme provides universal control and we present two typical applications: polarizing the nuclear spin and measuring nuclear spin free induction decay signals, both without applying radio-frequency pulses. This scheme is versatile as it can be implemented over a wide range of magnetic field strengths and at any temperature.