Imaging a network of 50 coupled spins with a single spin quantum sensor

Optically addressable solid-state defects have emerged as a versatile platform for quantum sensing, simulations and networks. Pioneering experiments have shown the sensing, imaging, and control of nuclear spin systems using single electron-spin defects. However, the size and complexity of the systems that could be imaged have been constrained by the limited spectral resolution of current methods. Here, we demonstrate the complete mapping of a network of 50 coupled spins through novel correlated sensing schemes using a single nitrogen-vacancy center in diamond. Our results provide new opportunities for quantum simulations of many-body physics by greatly increasing the number of accessible spins. Furthermore, the methods developed here might be applicable for nano- and atomic-scale magnetic resonance imaging of complex spin systems outside the host material.