2026-06-01T02:23:14Zhttps://docta.ucm.es/rest/oai/request

oai:docta.ucm.es:20.500.14352/519172023-08-25T16:08:46Zcom_20.500.14352_14col_20.500.14352_15

First Order Phase Transition in a 3D disordered system Fernández Pérez, Luis Antonio Gordillo Guerrero, A. Martín Mayor, Víctor Ruiz Lorenzo, J. J. 53 51-73 Field ising-model Bond Potts models Critical exponents Critical-behavior Monte-Carlo. Física (Física) Física-Modelos matemáticos 22 Física © 2008 American Institute of Physics. BIFI International Congress (111th. 2008. Zaragoza, Spain). This work has been partially supported by MEC through contracts No. FIS2004-0I399, FIS2006-08533-C03, FIS2007-60977 and by CAM and BSCH. Computer time was obtained at BIFI, UCM and UEx and (~ 50%) in the Mare Nostrum. The authors thankfully acknowledge the computer resources and technical expertise provided by the Barcelona Supercomputing Center. 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. MEC (Spain) CAM (Spain) BSCH Depto. de Física Teórica Fac. de Ciencias Físicas TRUE pub 2023-06-20T11:17:11Z 2023-06-20T11:17:11Z 2008 journal article https://hdl.handle.net/20.500.14352/51917 0094-243x 10.1063/1.3033359 eng FIS2004-0I399 FIS2006-08533-C03 FIS2007-60977 open access application/pdf American Institute of Physics