Direct Readout of Nitrogen-Vacancy Hybrid-Spin Quantum Register in Diamond by Photon Arrival Time Analysis

TL;DR

This paper presents a novel, efficient method for reading hybrid-spin states in nitrogen-vacancy centers in diamond using photon arrival times, significantly reducing measurement time while maintaining high fidelity.

Contribution

The authors introduce a single-pulse readout technique based on excited state level anti-crossing, enabling faster and potentially full-state quantum tomography in NV centers.

Findings

Achieves same population readout as traditional methods with tenfold less time

Maintains high fidelity in spin state measurement

Potential to extend to full quantum state tomography

Abstract

Quantum state readout plays a pivotal role in quantum technologies, spanning applications in sensing, computation, and secure communication. In this work, we introduce a new approach for efficiently reading populations of hybrid-spin states in the nitrogen-vacancy center of diamond using a single laser pulse, which utilizes the excited state level anti-crossing mechanism at around 500 Gs. Reading spin state populations through this approach achieves the same outcome as traditional quantum state diagonal tomography but significantly reduces the experimental time by an order of magnitude while maintaining fidelity. Moreover, this approach may be extended to encompass full-state tomography, thereby obviating the requirement for a sequence of spin manipulations and mitigating errors induced by decoherence throughout the procedure.