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arXiv · 2202.11115

Certain exact many-body results for Hubbard model ground states testable in small quantum dot arrays

Donovan Buterakos·Sankar Das Sarma
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Abstract

We present several interesting phenomena related to flatband ferromagnetism in the Hubbard model. The first is a mathematical theorem stating certain conditions under which a flatband ferromagnetic must necessarily be degenerate with a nonferromagnetic state. This theorem is generally applicable and geometry-independent, but holds only for a small number of holes in an otherwise filled band. The second phenomenon is a peculiar example where the intuition fails that particles prefer to doubly occupy low-energy states before filling higher-energy states. Lastly, we show a pattern of ferromagnetism which appears in small pentagonal and hexagonal plaquettes at filling factors of roughly 3/10 and 1/4. These examples require only a small number of lattice sites, and may be observable in quantum dot arrays currently available as laboratory spin qubit arrays.

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Donovan Buterakos, Sankar Das Sarma. 2022-02-22. Certain exact many-body results for Hubbard model ground states testable in small quantum dot arrays. https://doi.org/10.1103/physrevb.107.014403

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