Quadratic dispersion relations in gapless frustration-free systems

Fuente: arXiv
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Main Authors: Masaoka, Rintaro, Soejima, Tomohiro, Watanabe, Haruki
Format: Preprint
Published: 2024
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author Masaoka, Rintaro
Soejima, Tomohiro
Watanabe, Haruki
author_facet Masaoka, Rintaro
Soejima, Tomohiro
Watanabe, Haruki
contents Recent case-by-case studies revealed that the dispersion of low energy excitations in gapless frustration-free Hamiltonians is often quadratic or softer. In this work, we argue that this is actually a general property of such systems. By combining a previous study by Bravyi and Gosset and the min-max principle, we prove this hypothesis for models with local Hilbert spaces of dimension two that contains only nearest-neighbor interactions on cubic lattice. This may be understood as a no-go theorem realizing gapless phases with linearly dispersive excitations in frustration-free Hamiltonians. We also provide examples of frustration-free Hamiltonians in which the plane-wave state of a single spin flip does not constitute low energy excitations.
format Preprint
id arxiv_https___arxiv_org_abs_2406_06414
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Quadratic dispersion relations in gapless frustration-free systems
Masaoka, Rintaro
Soejima, Tomohiro
Watanabe, Haruki
Strongly Correlated Electrons
Other Condensed Matter
Statistical Mechanics
Quantum Physics
Recent case-by-case studies revealed that the dispersion of low energy excitations in gapless frustration-free Hamiltonians is often quadratic or softer. In this work, we argue that this is actually a general property of such systems. By combining a previous study by Bravyi and Gosset and the min-max principle, we prove this hypothesis for models with local Hilbert spaces of dimension two that contains only nearest-neighbor interactions on cubic lattice. This may be understood as a no-go theorem realizing gapless phases with linearly dispersive excitations in frustration-free Hamiltonians. We also provide examples of frustration-free Hamiltonians in which the plane-wave state of a single spin flip does not constitute low energy excitations.
title Quadratic dispersion relations in gapless frustration-free systems
topic Strongly Correlated Electrons
Other Condensed Matter
Statistical Mechanics
Quantum Physics
url https://arxiv.org/abs/2406.06414