Microcanonical entropy for small magnetisations

Abstract

Physical quantities obtained from the microcanonical entropy surfaces of classical spin systems show typical features of phase transitions already in finite systems. It is demonstrated that the singular behaviour of the microcanonically defined order parameter and susceptibility can be understood from a Taylor expansion of the entropy surface. The general form of the expansion is determined from the symmetry properties of the microcanonical entropy function with respect to the order parameter. The general findings are investigated for the four-state vector Potts model as an example of a classical spin system.

15 pages, 7 figures

References in corpus (1)

• Symmetries of microcanonical entropy surfaces

Cited by in corpus (8)

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• On the mean-field spherical model
• Boltzmann entropy and the microcanonical ensemble
• Finite-size behaviour of the microcanonical specific heat
• Microcanonical scaling in small systems
• Density of states determined from Monte Carlo simulations
• Critical properties of the spherical model in the microcanonical formalism
• The density of states of classical spin systems with continuous degrees of freedom