Probing dynamics of a two-dimensional dipolar spin ensemble

Abstract

One of the central challenges of modern statistical physics is understanding the thermalization dynamics of quantum many-body systems at the microscopic level. In this thesis, we describe an experimental study of individual spin dynamics in a two-dimensional ensemble of electron spins on the surface of a diamond crystal. A near-surface NV center is used as a nanoscale magnetic sensor to probe individual spin correlation dynamics in a dipolar interacting spin ensemble. For each spin, the rate of relaxation of spin projection along the bias magnetic field is consistently much slower than the dipolar interaction strengths with its nearest neighbors and is strongly correlated with the timescale of the local magnetic field fluctuation. We present a quantitative model based on dynamic resonance counting arguments that explains these observations. Furthermore, we use resonant spin-lock driving to control the effective strength of the local magnetic fields and demonstrate the role of dynamical disorder in different regimes. In the regime of suppressed extrinsic disorder, we use dynamic mean field methods to explain our experimental observations. The work presented in this thesis paves the way towards a microscopic study of quantum thermalization in two-dimensional strongly interacting disordered spin ensembles.