Show simple item record

dc.contributor.authorGarcía Ramos, José Enrique 
dc.contributor.authorDukelsky, J.
dc.contributor.authorPérez Fernández, Pedro
dc.contributor.authorArias Carrasco, José Miguel
dc.identifier.issn2469-9993 (electrónico)
dc.description.abstractBackground: The Agassi model [D. Agassi, Nucl. Phys. A 116, 49 (1968)] is an extension of the Lipkin-Meshkov-Glick (LMG) model [H. J. Lipkin, N. Meshkov, and A. J. Glick, Nucl. Phys. 62, 188 (1965)] that incorporates the pairing interaction. It is a schematic model that describes the interplay between particle-hole and pair correlations. It was proposed in the 1960s by D. Agassi as a model to simulate the properties of the quadrupole plus pairing model. Purpose: The aim of this work is to extend a previous study by Davis and Heiss [J. Phys. G: Nucl. Phys. 12, 805 (1986)] generalizing the Agassi model and analyze in detail the phase diagram of the model as well as the different regions with coexistence of several phases. Method: We solve the model Hamiltonian through the Hartree-Fock-Bogoliubov (HFB) approximation, introducing two variational parameters that play the role of order parameters. We also compare the HFB calculations with the exact ones. Results: We obtain the phase diagram of the model and classify the order of the different quantum phase transitions appearing in the diagram. The phase diagram presents broad regions where several phases, up to three, coexist. Moreover, there is also a line and a point where four and five phases are degenerated, respectively. Conclusions: The phase diagram of the extended Agassi model presents a rich variety of phases. Phase coexistence is present in extended areas of the parameter space. The model could be an important tool for benchmarking novel many-body approximations.es_ES
dc.publisherAmerican Physical Societyes_ES
dc.rightsAtribución-NoComercial-SinDerivadas 3.0 España*
dc.subject.otherAgassi model
dc.subject.otherQuantum phase transitions
dc.subject.otherPhase diagram
dc.titlePhase diagram of an extended Agassi modeles_ES

Files in this item

This item appears in the following Collection(s)

Show simple item record

Atribución-NoComercial-SinDerivadas 3.0 España
Except where otherwise noted, this item's license is described as Atribución-NoComercial-SinDerivadas 3.0 España

Copyright © 2008-2010. ARIAS MONTANO. Repositorio Institucional de la Universidad de Huelva
Contact Us | Send Feedback |