Eta-Pairing in Hubbard Models: From Spectrum Generating Algebras to Quantum Many-Body Scars

By Sanjay Moudgalya, N. Regnault, Bogdan Andrei Bernevig. 2020

149 citations recorded by the source corpus.

We revisit the $\eta$-pairing states in Hubbard models and explore their connections to quantum many-body scars to discover a universal scars mechanism. $\eta$-pairing occurs due to an algebraic structure known as a Spectrum Generating Algebra (SGA), giving rise to equally spaced towers of eigenstates in the spectrum. We generalize the original $\eta$-pairing construction and show that several Hubbard-like models on arbitrary graphs exhibit SGAs, including ones with disorder and spin-orbit coupling. We further define a Restricted Spectrum Generating Algebra (RSGA) and give examples of perturbations to the Hubbard-like models that preserve an equally spaced tower of the original model as eigenstates. The states of the surviving tower exhibit a sub-thermal entanglement entropy, and we analytically obtain parameter regimes for which they lie in the bulk of the spectrum, showing that they are exact quantum many-body scars. The RSGA framework also explains the equally spaced towers of eigenstates in several well-known models of quantum scars, including the AKLT model.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/32fee0bce79e74bdf34c1708b89eb366778d9bcf

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In Atomic and Molecular Physics, and Optics

  1. V. Khemani
  2. D. Abanin
  3. Anushya Chandran
  4. Maksym Serbyn
  5. Roderich Moessner
  6. Z. Papi'c
  7. Thomas Iadecola
  8. Tomaz Prosen

In Condensed Matter Physics

  1. D. Abanin
  2. Maksym Serbyn
  3. V. Khemani
  4. Anushya Chandran
  5. Z. Papi'c
  6. Roderich Moessner
  7. Tomaz Prosen
  8. J. Moore

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