Persistent dark states in anisotropic central spin models
Abstract
Long-lived dark states, in which an experimentally accessible qubit is not in thermal equilibrium with a surrounding spin bath, are pervasive in solid-state systems. We explain the ubiquity of dark states in a large class of inhomogeneous central spin models using the proximity to integrable lines with exact dark eigenstates. At numerically accessible sizes, dark states persist as eigenstates at large deviations from integrability, and the qubit retains memory of its initial polarization at long times. Although the eigenstates of the system are chaotic, exhibiting exponential sensitivity to small perturbations, they do not satisfy the eigenstate thermalization hypothesis. Rather, we predict long relaxation times that increase exponentially with system size. We propose that this intermediate chaotic but non-ergodic regime characterizes mesoscopic quantum dot and diamond defect systems, as we see no numerical tendency towards conventional thermalization with a finite relaxation time.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 30, 2020
- Source ID
- 10.1038/s41598-020-73015-1
Entities
People
- Anatoli Polkovnikov
- Anushya Chandran
- Mohit Pandey
- Pieter W Claeys
- Tamiro Villazon
Organizations
- Air Force Office of Scientific Research
- Belgian American Educational Foundation
- Engineering and Physical Sciences Research Council
- National Science Foundation