Comment on “Z2-slave-spin theory for strongly correlated fermions”

• Autor(a) principal: Ferraz Filho, Álvaro
• Data de Publicação: 2013
• Outros Autores: Kochetov, Evgeny
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRN
• Texto Completo: https://repositorio.ufrn.br/jspui/handle/123456789/28840
• topic: Teoria do spin Z2

The authors of Ref. 1 introduced a new slave-spin (SS) mean-field (MF) approach to the Hubbard model of strongly correlated electrons in terms of Ising spins and standard fermion operators by constructing an enlarged Hilbert space with both physical and unphysical states. The purpose of this construction is clear: this formulation involves a much smaller number of slave fields, compared with more standard slave particle frameworks. In this way, the complexity of the original model is reduced to a more readily tractable system of Ising spins in a transverse field coupled to free fermions. In this Comment, we show that the unphysical states are not properly excluded, and despite the claimed good agreement with previous results, the consistency of their MF theory is unjustified