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Continuous phase transitions with a convex dip in the microcanonical entropy

Hans Behringer·Michel Pleimling
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Abstract

The appearance of a convex dip in the microcanonical entropy of finite systems usually signals a first order transition. However, a convex dip also shows up in some systems with a continuous transition as for example in the Baxter-Wu model and in the four-state Potts model in two dimensions. We demonstrate that the appearance of a convex dip in those cases can be traced back to a finite-size effect. The properties of the dip are markedly different from those associated with a first order transition and can be understood within a microcanonical finite-size scaling theory for continuous phase transitions. Results obtained from numerical simulations corroborate the predictions of the scaling theory.

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Hans Behringer, Michel Pleimling. 2006-06-12. Continuous phase transitions with a convex dip in the microcanonical entropy. https://doi.org/10.1103/physreve.74.011108

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