eta-pairing in Hubbard models: From spectrum generating algebras to quantum many-body scars

Article

关键词: LONG-RANGE ORDER;    STATISTICAL-MECHANICS;    THERMALIZATION;    SUPERCONDUCTIVITY;    SYMMETRY;    STATES;    CHAOS;   

DOI  :  10.1103/PhysRevB.102.085140

来源: SCIE

【 摘 要 】

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 subthermal 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 Affleck-Kennedy-Lieb-Tasaki model.

【 授权许可】

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