High Sensitivity Nanoscale NMR via Quantum Memory Enhanced Multipoint Correlation Spectroscopy

Solid-state spin sensors offer a powerful platform for nuclear magnetic resonance (NMR) spectroscopy at the micro- and nanoscale. While most nanoscale NMR experiments rely on a single sensor spin, using spin ensembles can significantly improve sensitivity. We introduce quantum memory enhanced multipoint correlation spectroscopy, a method that integrates the advantages of correlation spectroscopy and quantum heterodyne detection (QDyne) to enable time-efficient measurements with spin ensembles at the nanoscale. We develop a theoretical framework describing this approach and demonstrate an experimental proof of concept using a nitrogen-vacancy (NV) center in diamond. Our measurements achieve sub-hertz precision in estimating signal frequency, illustrating the potential of this technique for high-resolution, nanoscale NMR spectroscopy with statistically polarized samples.