Probing many-body noise in a strongly interacting two-dimensional spin ensemble ---- Part I: Experiment

Two-dimensional systems of strongly interacting, highly coherent, and optically addressable spins present opportunities in both quantum simulation and sensing. While obtaining such a system in a solid-state platform has traditionally proved challenging, recent progress in delta-doped diamond growth has enabled the fabrication of a novel sample containing a thin layer of nitrogen-vacancy (NV) and substitutional nitrogen (P1) defects in a diamond lattice. We expect that this hybrid NV-P1 spin system is two-dimensional, i.e., that the layer thickness is smaller than the average spin-spin spacing; however, measuring the dimensionality conclusively presents a new and separate challenge. In this talk, we establish the two-dimensional nature of our sample via a characterization technique based upon the system's intrinsic many-body dynamics. In particular, by studying the decoherence dynamics of the NV spins, we directly measure the dimensionality of the interacting P1 spin ensemble. This work opens the door to understanding both static and dynamical properties of many-body systems more broadly, by generalizing our method of mapping dimensionality onto the dynamics of an NV probe spin.