Fast coherent control of nitrogen-14 spins associated with nitrogen-vacancy centers in diamonds using dynamical decoupling

TL;DR

This paper demonstrates a fast method for controlling nitrogen-14 nuclear spins in diamond NV centers using dynamical decoupling and an effective transverse coupling induced by a weak off-axis magnetic field, significantly reducing gate times.

Contribution

The study introduces a novel technique to generate effective transverse hyperfine coupling for nitrogen spins, enabling rapid conditional rotation gates in NV centers.

Findings

Achieved nitrogen-14 spin control within 4.2 microseconds.

Demonstrated population transfer from electron to nitrogen spins in 8.7 microseconds.

Applicable to both single and ensemble NV centers.

Abstract

A nitrogen-vacancy (NV) center in a diamond enables the access to an electron spin, which is expected to present highly sensitive quantum sensors. Although exploiting a nitrogen nuclear spin improves the sensitivity, manipulating it using a resonant pulse requires a long gate time owing to its small gyromagnetic ratio. Another technique to control nuclear spins is a conditional rotation gate based on dynamical decoupling, which is faster but unavailable for nitrogen spins owing to the lack of transverse hyperfine coupling with the electron spin. In this study, we generated effective transverse coupling by applying a weak off-axis magnetic field. An effective coupling depends on the off-axis field; the conditional rotation gate on the nitrogen-14 spins of an NV center was demonstrated within 4.2 {\mu}s under an 1.8% off-axis field and a longitudinal field of approximately 280 mT. We estimated that a population transfer from the electron to nitrogen spins can be implemented with 8.7 {\mu}s. Our method is applicable to an ensemble of NV centers, in addition to a single NV center.