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arXiv · 2108.02414

Construction of interacting flat-band models by molecular-orbital representation: Correlation functions, energy gap, and entanglement

Tomonari Mizoguchi·Yoshihito Kuno·Yasuhiro Hatsugai
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Abstract

We calculate correlation functions of exactly-solvable one-dimensional flat-band models by utilizing the "molecular-orbital" representation. The models considered in this paper have a gapped ground state with flat-band being fully occupied, even in the presence of the interaction. In this class of models, the space spanned by the "molecular-orbitals" is the co-space of that spanned by the flat bands. Thanks to this property, the correlation functions are calculated by using the information of the molecular-orbitals rather than the explicit forms of the flat-band wave functions, which simplifies the calculations. As a demonstration, several one-dimensional models and their correlation functions are presented. We also calculate the entanglement entropy by using the correlation function.

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Tomonari Mizoguchi, Yoshihito Kuno, Yasuhiro Hatsugai. 2021-08-05. Construction of interacting flat-band models by molecular-orbital representation: Correlation functions, energy gap, and entanglement. https://doi.org/10.1093/ptep/ptac015

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