• Corpus ID: 211171460

Many-body delocalization via symmetry emergence

@article{Srivatsa2020ManybodyDV,
  title={Many-body delocalization via symmetry emergence},
  author={N. S. Srivatsa and Roderich Moessner and Anne Ellerup Nielsen},
  journal={arXiv: Disordered Systems and Neural Networks},
  year={2020}
}

• N. Srivatsa, R. Moessner, A. Nielsen
• Published 18 February 2020
• Physics
• arXiv: Disordered Systems and Neural Networks

Many-body localization (MBL) provides a mechanism to avoid thermalization in many-body quantum systems. Here, we show that an {\it emergent} symmetry can protect a state from MBL. Specifically, we propose a $\Z_2$ symmetric model with nonlocal interactions, which has an analytically known, SU(2) invariant, critical ground state. At large disorder strength all states at finite energy density are in a glassy MBL phase, while the lowest energy states are not. These do, however, localize when a perturbation destroys the emergent SU(2) symmetry. The model also provides an example of MBL in the presence of nonlocal, disordered interactions that are more structured than a power law. The presented ideas raise the possibility of an `inverted quantum scar', in which a state that does not exhibit area law entanglement is embedded in an MBL spectrum, which does.