Entanglement-enhanced nanoscale single-spin sensing
Article metadata
Article Date: 26 November 2025
Article URL: https://www.nature.com/articles/s41586-025-09790-6
Article Image: Extended data figure 1
Summary
This Nature paper demonstrates entanglement-enhanced sensing at the nanoscale using pairs of nitrogen-vacancy (NV) centres in diamond to detect and locate a single nearby “dark” spin with improved sensitivity. The team prepares entangled NV-pair states and uses double electron–electron resonance (DEER) techniques to measure effective couplings to a target spin (labelled DS1). By combining measurements under different external magnetic-field directions and exploiting the entangled state, they achieve more precise positioning and stronger signal contrast than with single-spin probes. The work includes experimental characterisation, decoherence analysis, identification and control of the dark spin, and sensitivity estimates, with data and code available from the authors on request and extensive supplementary material provided.
Key Points
- Entangled NV-pair states are prepared and used as a correlated quantum sensor to probe a nearby single-spin (DS1) at the nanoscale.
- Measurement protocols combine entanglement-enhanced DEER spectroscopy with vector magnetic-field control to extract effective couplings and spatial constraints on the dark spin.
- Using entanglement gives improved sensitivity and positional precision compared with single NV sensors, enabling better detection of weak couplings in a noisy solid-state environment.
- Authors present decoherence analysis, dark-spin identification, and a roadmap for initializing and entangling NV–dark-spin systems for sensing tasks.
- Comprehensive supplementary information and peer-review files are available; source data are provided with the paper and additional data/code can be requested from the corresponding authors.
Context and relevance
This study sits squarely in the advancing field of quantum sensing with solid-state spins, building on decades of NV-centre magnetometry and recent progress in entanglement-enhanced metrology. It connects to ongoing trends: pushing sensitivity beyond classical (standard quantum) limits, achieving nanoscale spectroscopic and imaging capability under practical conditions, and exploiting correlated quantum resources to tackle noise and weak signals. The approach is relevant to researchers working on nanoscale magnetic resonance, single-spin detection, quantum-enhanced measurement protocols and materials characterisation (2D magnets, graphene, biological samples and high-pressure studies are typical application areas).
Why should I read this?
Short answer: if you care about squeezing more signal out of tiny magnetic sources, this is gold. The paper shows how entanglement between solid-state spins can turn a finicky, noisy nanoscale probe into a noticeably sharper and more reliable detector — they actually locate a single nearby spin more precisely than you’d get with lone NV sensors. If you’re into quantum sensors, materials at the nanoscale or pushing measurement limits, this saves you time by summarising an elegant experimental route to real gains in sensitivity and localisation.
Author’s take
Punchy and important — the team demonstrates an achievable, experimentally validated step towards quantum-enhanced nanoscale sensing. This isn’t just a toy demonstration: it ties together practical entanglement preparation, measurement protocols and localisation strategies that others can build on.