Münster 1997 – scientific programme
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DY: Dynamik und Statistische Physik
DY 19: Poster II
DY 19.56: Poster
Thursday, March 20, 1997, 09:30–12:30, Z
Softening of First-Order Phase Transition on Quenched Random Gravity Graphs — •W. Janke2, C.F. Baillie1, and D.A. Johnston3 — 1Department of Computer Science, University of Colorado, Boulder, CO 80309, USA — 2Institut f"ur Physik, WA331, Johannes Gutenberg–Universit"at Mainz, D-55099 Mainz — 3Department of Mathematics, Heriot-Watt University, Edinburgh, EH14 4AS, Scotland
We perform extensive Monte Carlo simulations of the 10-state Potts model on quenched two-dimensional Φ3 gravity graphs to study the effect of quenched coordination number randomness on the nature of the phase transition, which is strongly first order on regular lattices. The numerical data provides strong evidence that, due to the quenched randomness, the discontinuous first-order phase transition of the pure model is softened to a continuous transition, representing presumably a new universality class [1]. This result is in striking contrast to a recent Monte Carlo study of the 8-state Potts model on two-dimensional Poissonian random lattices of Voronoi/Delaunay type, where the phase transition clearly stayed of first order [2], but is in qualitative agreement with results for quenched bond randomness on regular lattices. A precedent for such softening with connectivity disorder is known: in the 10-state Potts model on annealed Φ3 gravity graphs a continuous transition is also observed.
[1] C.F. Baillie, W. Janke, and D.A. Johnston, Phys. Lett. B388 (1996) 14; and preprint in preparation.
[2] W. Janke and R. Villanova, Phys. Lett. A209 (1995) 179.