First Order Phase Transition in a 3D disordered system

We present a detailed numerical study on the effects of adding quenched impurities to a three dimensional system which in the pure case undergoes a strong first order phase transition (specifically, the ferromagnetic/paramagnetic transition of the site-diluted four states Potts model). We can state...

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Detalles Bibliográficos
Autores: Fernández Pérez, Luis Antonio, Gordillo Guerrero, A., Martín Mayor, Víctor, Ruiz Lorenzo, J. J.
Tipo de recurso: artículo
Fecha de publicación:2008
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/51917
Acceso en línea:https://hdl.handle.net/20.500.14352/51917
Access Level:acceso abierto
Palabra clave:53
51-73
Field ising-model
Bond Potts models
Critical exponents
Critical-behavior
Monte-Carlo.
Física (Física)
Física-Modelos matemáticos
22 Física
Descripción
Sumario:We present a detailed numerical study on the effects of adding quenched impurities to a three dimensional system which in the pure case undergoes a strong first order phase transition (specifically, the ferromagnetic/paramagnetic transition of the site-diluted four states Potts model). We can state that the transition remains first-order in the presence of quenched disorder (a small amount of it) but it turns out to be second order as more impurities are added. A tricritical point, which is studied by means of Finite-Size Scaling, separates the first-order and second-order parts of the critical line. The results were made possible by a new definition of the disorder average that avoids the diverging-variance probability distributions that arise using the standard methodology. We also made use of a recently proposed microcanonical Monte Carlo method in which entropy, instead of free energy, is the basic quantity.