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Main Authors: Lee, Sanghoon, Andreanov, Alexei, Sedrakyan, Tigran, Flach, Sergej
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2403.05084
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author Lee, Sanghoon
Andreanov, Alexei
Sedrakyan, Tigran
Flach, Sergej
author_facet Lee, Sanghoon
Andreanov, Alexei
Sedrakyan, Tigran
Flach, Sergej
contents We investigate 1D and 2D cross-stitch lattices with hard-core bosons and analytically construct exact groundstates that feature macroscopic degeneracy. The construction relies on the presence of a flatband in the single particle spectrum and the orthogonality of the associated compact localized states (CLS). Up to filling fraction $ν=1/2$, the groundstate is constructed by occupying the CLS. Exactly at $ν=1/2$, the groundstate becomes a Wigner crystal. For higher filling fractions, the groundstate is constructed by filling the CLS sites completely one by one. Macroscopic degeneracy arises from the multiple choices available when occupying or filling the CLS sites. An occupied CLS acts as an impenetrable barrier for bosons both in 1D and 2D, leading to Hilbert space fragmentation. A similar phenomenology also holds for hard-core bosons on the diamond chain and its higher dimensional generalizations. We also discuss the mapping of these hard-core models onto spin models with quantum many-body scars.
format Preprint
id arxiv_https___arxiv_org_abs_2403_05084
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Trapping Hard-Core Bosons in Flatband Lattices
Lee, Sanghoon
Andreanov, Alexei
Sedrakyan, Tigran
Flach, Sergej
Strongly Correlated Electrons
We investigate 1D and 2D cross-stitch lattices with hard-core bosons and analytically construct exact groundstates that feature macroscopic degeneracy. The construction relies on the presence of a flatband in the single particle spectrum and the orthogonality of the associated compact localized states (CLS). Up to filling fraction $ν=1/2$, the groundstate is constructed by occupying the CLS. Exactly at $ν=1/2$, the groundstate becomes a Wigner crystal. For higher filling fractions, the groundstate is constructed by filling the CLS sites completely one by one. Macroscopic degeneracy arises from the multiple choices available when occupying or filling the CLS sites. An occupied CLS acts as an impenetrable barrier for bosons both in 1D and 2D, leading to Hilbert space fragmentation. A similar phenomenology also holds for hard-core bosons on the diamond chain and its higher dimensional generalizations. We also discuss the mapping of these hard-core models onto spin models with quantum many-body scars.
title Trapping Hard-Core Bosons in Flatband Lattices
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2403.05084