Quantum Sensing via Large Spin-Clusters in Solid-State NMR: Optimal coherence order for practical sensing

TL;DR

This paper demonstrates how large clusters of correlated nuclear spins in solid-state NMR can be used for quantum sensing, revealing an optimal coherence order that maximizes sensitivity to control-field jitters.

Contribution

It introduces a method to identify the optimal coherence order in large spin clusters for enhanced quantum sensing in solid-state NMR.

Findings

Large spin clusters can detect pulse-width jitters at nanosecond precision.

An optimal maximum coherence order exists that maximizes sensing efficiency.

Numerical modeling supports the experimental findings and quantum Fisher information estimates.

Abstract

Quantum entanglement has long been recognized as an important resource for quantum sensing. In this work, we demonstrate the use of multiple-quantum solid-state NMR for quantum sensing by creating, manipulating, and detecting large clusters of correlated nuclear spins. We show that such clusters can sensitively detect pulse-width jitters in radio-frequency control fields at the level of tens of nanoseconds. By analyzing the response of high-order quantum coherences to these control-field jitters, we investigate the critical interplay between the enhanced sensitivity offered by large coherence orders, their relative distributions, and their varying susceptibility to decoherence. We further demonstrate that, even within a non-uniform distribution of coherence orders, there exists an optimal maximum coherence order that maximizes sensing efficiency. To support our interpretation, we supplement the experimental results with a simplified numerical model that estimates the corresponding quantum Fisher information. These results support the solid-state NMR platform as a valuable testbed for investigating many-body quantum metrology protocols.