Journal article
Exact excited states of nonintegrable models
S Moudgalya, S Rachel, BA Bernevig, N Regnault
Physical Review B | AMER PHYSICAL SOC | Published : 2018
Abstract
We discuss a method of numerically identifying exact energy eigenstates for a finite system, whose form can then be obtained analytically. We demonstrate our method by identifying and deriving exact analytic expressions for several excited states, including an infinite tower, of the one-dimensional spin-1 Affleck-Kennedy-Lieb-Tasaki (AKLT) model, a celebrated nonintegrable model. The states thus obtained for the AKLT model can be interpreted as from one to an extensive number of quasiparticles on the ground state or on the highest excited state when written in terms of dimers. Included in these exact states is a tower of states spanning energies from the ground state to the highest excited s..
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Awarded by David and Lucile Packard Foundation
Funding Acknowledgements
We thank Paul Fendley for encouragement and initial discussions on this work, and Elliot Lieb and David Huse for useful discussions. B.A.B. wishes to thank Ecole Normale Superieure, UPMC Paris, and Donostia International Physics Center for their generous sabbatical hosting during some of the stages of this work. S.R. acknowledges funding from the DFG through SFB 1143 and an Australian Research Council Future Fellowship (FT180100211). B.A.B. acknowledges support for the analytic work Department of Energy de-sc0016239, a Simons Investigator Award, the Packard Foundation, and the Schmidt Fund for Innovative Research. The computational part of the Princeton work was performed under NSF EAGER Grant No. DMR-1643312, ONR-N00014-14-1-0330, ARO MURI W911NF-12-1-0461, and NSF-MRSEC DMR-1420541.