ITAMP Seminar
Date: Thursday, September 29th
Time: 12:00-1:30 pm
Pizza will be served.
Location: B-106 @ Center for Astrophysics (60 Garden Street)
Directions: after entering the lobby of the CfA, turn right to enter
the hallway of the B building. In the hallway, turn right again, and
B-106 is there.
Speaker: Soonwon Choi (Lukin group)
Title: Critical thermalization of a disordered dipolar
spin system in diamond
Abstract: Nearly sixty years ago, Anderson predicted
that the interplay between long-range couplings and disorder in
quantum systems can lead to a novel regime of slow, sub-diffusive
thermalization. This is in stark contrast to both conventional
ergodic system and many-body localized systems. In this talk, we
present both theory and experimental observation of such critical
thermalization in a three dimensional ensemble of ~10^6 spins
coupled via dipolar interactions. By coherently manipulating the
spin states of nitrogen vacancy color centers in diamond, we observe
that two groups of oppositely polarized spins approach their
equilibrium state via slow, sub-exponential relaxation dynamics,
that is consistent with power laws with disorder-dependent
exponents. This behavior is modified at late time owing to many-body
interactions. These observations are quantitatively explained by a
resonance counting theory, which reveals the subtle role of
long-range interactions in the system.