Hybrid-spin decoupling for noise-resilient DC quantum sensing

TL;DR

This paper introduces a hybrid-spin decoupling technique that enhances noise resilience in DC quantum sensing, enabling detection of static signals amidst magnetic noise with broad frequency resistance.

Contribution

It presents a novel method for decoupling specific DC fields from magnetic noise using spin clusters with differential effects, significantly improving noise resistance in quantum sensors.

Findings

Achieves an order-of-magnitude increase in noise frequency resistance.

Demonstrates applicability to nitrogen-vacancy centers in diamond.

Potential for improved dark-matter detection and gradient sensing.

Abstract

The excellent sensitivities of quantum sensors are a double-edged sword: minuscule quantities can be observed, but any undesired signal acts as noise. This is challenging when detecting quantities that are obscured by such noise. Decoupling sequences improve coherence times and hence sensitivities, though only AC signals in narrow frequency bands are distinguishable. Alternatively, comagnetometers operate gaseous spin mixtures at high temperatures in the self-compensating regime to counteract slowly varying noise. These are applied with great success in various exotic spin-interaction searches. Here, we propose a method that decouples specific DC fields from DC and AC magnetic noise. It requires any spin cluster where the effect on each individual spin is different for the target field and local magnetic fields, which allows for a different approach compared to comagnetometers. The presented method has several key advantages, including an orders-of-magnitude increase in noise frequencies to which we are resistant. We explore electron-spin nuclear-spin pairs in nitrogen-vacancy centres in diamond, with a focus on their merit for light dark-matter searches. Other applications include gradient sensing, quantum memory, and gyroscopes.