Entangled Diamond Pairs Sharpen Quantum Vision

Detecting individual atomic spins is a fundamental challenge in physics, holding the key to advances in quantum chemistry and single-molecule magnetic resonance imaging. While nitrogen-vacancy (NV) centres—atomic defects in diamond—are powerful sensors, their ability to spot single spins is often hampered by environmental noise and a restricted sensing volume.

To overcome these limits, a new study demonstrates an ingenious protocol relying on quantum entanglement. Instead of using a single sensor, the approach employs pairs of entangled NV centres. These carefully engineered states work in tandem to amplify the signal from a target spin through quantum interference, while simultaneously cancelling out distracting background noise.

The performance boost is significant. Under ambient conditions, this entanglement-enhanced method achieves a 3.4-fold improvement in sensitivity and sharper spatial resolution by a factor of 1.6 compared to standard single NV centres. Crucially, the technique is sensitive enough to track 'metastable' single-spin dynamics, allowing researchers to observe stochastic transitions between different spin states directly.

This dual capability to resolve both static and dynamic features establishes a viable pathway for the atomic-scale characterisation of quantum interfaces. By harnessing the cooperative power of entanglement, scientists can now peer into the quantum realm with unprecedented clarity.