Failure of saturated ferromagnetism for the Hubbard model with two holes

Bálint Tóth

Research output: Contribution to journalArticle

Abstract

We consider the Hubbard model on a finite set of sites with nonpositive hopping matrix elements and infinitely strong on-site repulsion. Nagaoka's theorem states that in this model the relative ground state in the sector with one unoccupied site is maximally ferromagnetic. We show that this phenomenon is a consequence of a combinatorial coincidence valid in the one-hole regime only. In the case of more than one hole there is no reason to expect maximally ferromagnetic ground states. We prove this claim for the case of two holes for models defined on a class of graphs which contains all tori that are not too small. © 1991 Kluwer Academic Publishers.

Original languageEnglish
Pages (from-to)321-333
Number of pages13
JournalLetters in Mathematical Physics
Volume22
Issue number4
DOIs
Publication statusPublished - Aug 1991

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Ferromagnetism
Hubbard Model
Ground State
Coincidence
Finite Set
Torus
Sector
Valid
Graph in graph theory
Theorem
Model

Keywords

  • AMS subject classifications (1991): 81Q99, 81V70, 82B10

Cite this

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Failure of saturated ferromagnetism for the Hubbard model with two holes. / Tóth, Bálint.

In: Letters in Mathematical Physics, Vol. 22, No. 4, 08.1991, p. 321-333.

Research output: Contribution to journalArticle

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