Interaction-Enhanced Sensing in a Nanoscale Solid-State Quantum Platform

Electronic spins of nitrogen-vacancy (NV) centers in diamond are a leading platform for micro- and nanoscale magnetic sensing. They operate under ambient conditions, can be positioned in close proximity to target systems, and are biocompatible. Despite significant advances in solid-state quantum sensing, entanglement-enhanced metrology has remained challenging in these systems due to the short-range, anisotropic nature of dipolar interactions and faster decoherence compared to more isolated atomic platforms.

In this talk, I will first describe recent work employing a two-dimensional interacting NV ensemble and a novel many-body time-reversal protocol to achieve amplification of weak magnetic signals [1]. I will then present a new mechanism for generating metrologically useful collective nonlinearities in three-dimensional spin ensembles [2]. This approach leverages nanoscale magnetic field gradients and engineered SU(2)-symmetric interactions and is robust to intrinsic positional disorder, enabling interaction-induced metrological gain in solid-state spin systems.

Finally, I will highlight recent results demonstrating how the implementation of this engineered nonlinearity, combined with enhanced coherence times enabled by a new qubit encoding scheme [3], leads to substantial, practical improvements in magnetic sensing performance and measurements of spatial nanoscale magnetic correlations at tunable length scales.

[1] Gao, Haoyang, et al. Nature 646.8083 (2025): 68-73.

[2] Put, Piotr et al, arXiv:2506.11920v3 (2025)

[3] Gao, Haoyang, et al, arXiv:2512.09043 (2025).