TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.17.2.055
TI  - Gaussian state approximation of quantum many-body scars
PY  - 2024/08/15
UR  - https://scipost.org/SciPostPhys.17.2.055
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 17
IS  - 2
SP  - 055
A1  - Buijsman, Wouter
AU  - Bar Lev, Yevgeny
AB  - 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.
ER  -

@Article{10.21468/SciPostPhys.17.2.055,
	title={{Gaussian state approximation of quantum many-body scars}},
	author={Wouter Buijsman and Yevgeny Bar Lev},
	journal={SciPost Phys.},
	volume={17},
	pages={055},
	year={2024},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.17.2.055},
	url={https://scipost.org/10.21468/SciPostPhys.17.2.055},
}