Quasiprobability distribution functions for finite-dimensional discrete phase spaces: Spin-tunneling effects in a toy model

We show how quasiprobability distribution functions defined over N(2)-dimensional discrete phase spaces can be used to treat physical systems described by a finite space of states which exhibit spin-tunneling effects. This particular approach is then applied to the Lipkin-Meshkov-Glick model in orde...

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Detalhes bibliográficos
Autores: Marchiolli, Marcelo A. [UNESP], Silva, Evandro C. [UNESP], Galetti, Diogenes [UNESP]
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2009
País:Brasil
Recursos:Universidade Estadual Paulista (UNESP)
Repositorio:Repositório Institucional da UNESP
Idioma:inglés
OAI Identifier:oai:repositorio.unesp.br:11449/24514
Acesso em linha:http://dx.doi.org/10.1103/PhysRevA.79.022114
http://hdl.handle.net/11449/24514
Access Level:acceso abierto
Palavra-chave:energy gap
excited states
ground states
quantum theory
statistical distributions
Descrição
Resumo:We show how quasiprobability distribution functions defined over N(2)-dimensional discrete phase spaces can be used to treat physical systems described by a finite space of states which exhibit spin-tunneling effects. This particular approach is then applied to the Lipkin-Meshkov-Glick model in order to obtain the time evolution of the discrete Husimi function, and as a by-product the energy gap for a symmetric combination of ground and first excited states. Moreover, we also show how an angle-based potential approach can be efficiently employed to explain qualitatively certain features of the energy gap in terms of a spin tunneling. Entropy functionals are also discussed in this context. Such results reinforce not only the formalism per se but also the possibility of some future potential applications in other branches of physics.