2016/09/30 by Georg Kucsko, Soonwon Choi, Joonhee Choi +10 · 2 citations
Physics and Astronomy · #cond-mat.dis-nn #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.1103/physrevlett.121.023601
published as Phys. Rev. Lett. 121, 023601 (2018) · 16+31 pages, 4+12 figures, major updates on experiments, theory, and data analysis
arxiv created 2017/10/25 · arxiv updated 2018/07/18
Statistical mechanics underlies our understanding of macroscopic quantum systems. It is based on the assumption that out-of-equilibrium systems rapidly approach their equilibrium states, forgetting any information about their microscopic initial conditions. This fundamental paradigm is challenged by disordered systems, in which a slowdown or even absence of thermalization is expected. We report the observation of critical thermalization in a three dimensional ensemble of ∼ 106 electronic spins coupled via dipolar interactions. By controlling the spin states of nitrogen vacancy color centers in diamond, we observe slow, sub-exponential relaxation dynamics and identify a regime of power-law decay with disorder-dependent exponents; this behavior is modified at late times owing to many-body interactions. These observations are quantitatively explained by a resonance counting theory that incorporates the effects of both disorder and interactions.