Groupe de Physique Statistique

Equipe 106, Institut Jean Lamour

Articles dans des revues à comité de lecture
Actes de conférences invités
Actes de conférences
Non publié
Habilitation à diriger des recherches
Epistémologie, histoire des sciences
Articles à vocation pédagogique
Edition d'ouvrage
Chapitres de livre
Grp Travail
Theses, Postes

Articles dans des revues à comité de lecture

Stability of the Griffiths phase in the 2D Potts model with correlated disorder
Chatelain C
Condensed Matter Physics 17 (2014) 33601
DOI : 10.5488/CMP.17.33601
ArXiv : arxiv:1404.6431 [PDF]
HAL : hal-00983707

A Griffiths phase has recently been observed by Monte Carlo simulations in the 2D $q$-state Potts model with strongly correlated quenched random couplings. In particular, the magnetic susceptibility was shown to diverge algebraically with the lattice size in a broad range of temperatures. However, only relatively small lattice sizes could be considered so one can wonder whether this Griffiths phase will not shrink and collapse into a single point, the critical point, as the lattice size is increased to much larger values. In this paper, the 2D eight-state Potts model is numerically studied for four different disorder correlations. It is shown that the Griffiths phase cannot be explained as a simple spreading of local transition temperatures caused by disorder fluctuations. As a consequence, the vanishing of the latter in the thermodynamic limit does not necessarily imply the collapse of the Griffiths phase into a single point. In contrast, the width of the Griffiths phase is controlled by the disorder strength. However, for disorder correlations decaying slower than $1/r$, no cross-over to a more usual critical behavior could be observed as this strength is tuned to weaker values.

Haut de page