Gaussian state approximation of quantum many-body scars
Wouter Buijsman, Yevgeny Bar Lev
SciPost Phys. 17, 055 (2024) · published 15 August 2024
- doi: 10.21468/SciPostPhys.17.2.055
- Submissions/Reports
-
Abstract
Quantum many-body scars are atypical, highly nonthermal eigenstates embedded in a sea of thermal eigenstates that have been observed in, for example, kinetically constrained quantum many-body models. These special eigenstates are characterized by a bipartite entanglement entropy that scales as most logarithmically with the subsystem size. We use numerical optimization techniques to investigate if quantum many-body scars of the experimentally relevant PXP model can be well approximated by Gaussian states. Gaussian states are described by a number of parameters that scales quadratically with system size, thereby having a much lower complexity than generic quantum many-body states, for which this number scales exponentially. We find that while quantum many-body scars can typically be well approximated by (symmetrized) Gaussian states, this is not the case for ergodic (thermal) eigenstates. This observation suggests that the non-ergodic part of the PXP Hamiltonian is related to certain quadratic parent Hamiltonians, thereby hinting on the origin of the quantum many-body scars.
Authors / Affiliations: mappings to Contributors and Organizations
See all Organizations.- 1 2 Wouter Buijsman,
- 2 Yevgeny Bar Lev
- 1 Max-Planck-Institut für Physik komplexer Systeme / Max Planck Institute for the Physics of Complex Systems
- 2 אוניברסיטת בן-גוריון בנגב / Ben-Gurion University of the Negev [BGU]
- Israel Science Foundation [ISF]
- Kreitman School of Advanced Graduate Studies, Ben-Gurion University of the Negev
- National Science Foundation [NSF]
- United States - Israel Binational Science Foundation (through Organization: United States-Israel Binational Science Foundation [BSF])