Generalization of the Haldane conjecture to SU(n) chains

Recently, SU(3) chains in the symmetric and self-conjugate representations have been studied using field theory techniques. For certain representations, namely rank-p symmetric ones with p not a multiple of 3, it was argued that the ground state exhibits gapless excitations. For the remaining repres...

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Main Authors: Kyle Wamer, Miklós Lajkó, Frédéric Mila, Ian Affleck
Format: Article
Language:English
Published: Elsevier 2020-03-01
Series:Nuclear Physics B
Online Access:http://www.sciencedirect.com/science/article/pii/S0550321320300183
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author Kyle Wamer
Miklós Lajkó
Frédéric Mila
Ian Affleck
author_facet Kyle Wamer
Miklós Lajkó
Frédéric Mila
Ian Affleck
author_sort Kyle Wamer
collection DOAJ
description Recently, SU(3) chains in the symmetric and self-conjugate representations have been studied using field theory techniques. For certain representations, namely rank-p symmetric ones with p not a multiple of 3, it was argued that the ground state exhibits gapless excitations. For the remaining representations considered, a finite energy gap exists above the ground state. In this paper, we extend these results to SU(n) chains in the symmetric representation. For a rank-p symmetric representation with n and p coprime, we predict gapless excitations above the ground state. If p is a multiple of n, we predict a unique ground state with a finite energy gap. Finally, if p and n have a greatest common divisor 1<q<n, we predict a ground state degeneracy of n/q, with a finite energy gap. To arrive at these results, we derive a non-Lorentz invariant flag manifold sigma model description of the SU(n) chains, and use the renormalization group to show that Lorentz invariance is restored at low energies. We then make use of recently developed anomaly matching conditions for these Lorentz-invariant models. We also review the Lieb-Schultz-Mattis-Affleck theorem, and extend it to SU(n) models with longer range interactions.
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spelling doaj.art-d7419d3f1f28470384ba107cb5dd41cc2022-12-21T20:01:46ZengElsevierNuclear Physics B0550-32132020-03-01952Generalization of the Haldane conjecture to SU(n) chainsKyle Wamer0Miklós Lajkó1Frédéric Mila2Ian Affleck3Department of Physics and Astronomy and Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, B.C., V6T1Z1, Canada; Corresponding author.Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, SwitzerlandInstitute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, SwitzerlandDepartment of Physics and Astronomy and Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, B.C., V6T1Z1, CanadaRecently, SU(3) chains in the symmetric and self-conjugate representations have been studied using field theory techniques. For certain representations, namely rank-p symmetric ones with p not a multiple of 3, it was argued that the ground state exhibits gapless excitations. For the remaining representations considered, a finite energy gap exists above the ground state. In this paper, we extend these results to SU(n) chains in the symmetric representation. For a rank-p symmetric representation with n and p coprime, we predict gapless excitations above the ground state. If p is a multiple of n, we predict a unique ground state with a finite energy gap. Finally, if p and n have a greatest common divisor 1<q<n, we predict a ground state degeneracy of n/q, with a finite energy gap. To arrive at these results, we derive a non-Lorentz invariant flag manifold sigma model description of the SU(n) chains, and use the renormalization group to show that Lorentz invariance is restored at low energies. We then make use of recently developed anomaly matching conditions for these Lorentz-invariant models. We also review the Lieb-Schultz-Mattis-Affleck theorem, and extend it to SU(n) models with longer range interactions.http://www.sciencedirect.com/science/article/pii/S0550321320300183
spellingShingle Kyle Wamer
Miklós Lajkó
Frédéric Mila
Ian Affleck
Generalization of the Haldane conjecture to SU(n) chains
Nuclear Physics B
title Generalization of the Haldane conjecture to SU(n) chains
title_full Generalization of the Haldane conjecture to SU(n) chains
title_fullStr Generalization of the Haldane conjecture to SU(n) chains
title_full_unstemmed Generalization of the Haldane conjecture to SU(n) chains
title_short Generalization of the Haldane conjecture to SU(n) chains
title_sort generalization of the haldane conjecture to su n chains
url http://www.sciencedirect.com/science/article/pii/S0550321320300183
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