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DY: Fachverband Dynamik und Statistische Physik
DY 33: Critical Phenomena and Phase Transitions
DY 33.5: Vortrag
Mittwoch, 18. März 2015, 16:00–16:15, BH-N 334
Nonstandard Finite-Size Scaling at First-Order Phase Transitions with Macroscopic Low-Temperature Phase Degeneracy — Marco Mueller1, Desmond A. Johnston2, and •Wolfhard Janke1 — 1Institut für Theoretische Physik, Universität Leipzig, Postfach 100 920, 04009 Leipzig, Germany — 2Department of Mathematics, School of Mathematical and Computer Sciences, Heriot-Watt University, Edinburgh EH14 4AS, Scotland, UK
We show that the standard inverse system volume scaling for finite-size corrections at a first-order phase transition (i.e., 1/L3 for an L × L × L lattice in 3D) is transmuted to 1/L2 scaling if there is an exponential low-temperature phase degeneracy. The gonihedric Ising model which has a four-spin interaction, plaquette Hamiltonian provides an exemplar of just such a system. We use multicanonical Monte Carlo simulations of this model to generate high-precision data which provides strong confirmation of the nonstandard finite-size scaling law. The dual to the gonihedric model, which is an anisotropically coupled Ashkin-Teller model, has a similar degeneracy and
also displays the nonstandard scaling behaviour. A suitable “fuki-nuke” type order parameter and further potential applications of the transmuted finite-size scaling law will be briefly discussed.
M. Mueller, W. Janke, D.A. Johnston, Phys. Rev. Lett. 112 (2014) 200601;
M. Mueller, D.A. Johnston, W. Janke, Nucl. Phys. B 888 (2014) 214.