Publications (2)3.63 Total impact
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ABSTRACT: A large deviation technique is used to calculate the microcanonical entropy function s(v,m) of the meanfield ϕ 4 model as a function of the potential energy v and the magnetization m. As in the canonical ensemble, a continuous phase transition is found. An analytical expression is obtained for the critical energy v c (J) as a function of the coupling parameter J. Copyright EDP Sciences/Società Italiana di Fisica/SpringerVerlag 2006  [Show abstract] [Hide abstract]
ABSTRACT: A large deviation technique is applied to the meanfield model Phi4, providing an exact expression for the configurational entropy s(v,m) as a function of the potential energy v and the magnetization m. Although a continuous phase transition occurs at some critical energy vc, the entropy is found to be a real analytic function in both arguments, and it is only the maximization over m which gives rise to a nonanalyticity in s(v)=supm s(v,m). This mechanism of nonanalyticitygeneration by maximization over one variable of a real analytic entropy function is restricted to systems with longrange interactions and hasfor continuous phase transitionsthe generic occurrence of classical critical exponents as an immediate consequence. Furthermore, this mechanism can provide an explanation why, contradictory to the socalled topological hypothesis, the phase transition in the meanfield model need not be accompanied by a topology change in the family of constantenergy submanifolds.
Publication Stats
40  Citations  
3.63  Total Impact Points  
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Institutions

20052006

University of Bayreuth
 Institute of Physics
Bayreuth, Bavaria, Germany
