Regensburg 2007 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 21: Finite size effects at phase transitions II (session accompanying the symposium of the same name)
DY 21.4: Vortrag
Mittwoch, 28. März 2007, 14:45–15:00, H3
Fisher renormalized exponents in an Ising fluid? — •Wolfgang Fenz1, Reinhard Folk1, Igor Mryglod1,2, and Igor Omelyan1,2 — 1Institute for Theoretical Physics, Linz University, A-4040 Linz, Austria — 2Institute for Condensed Matter Physics, 1 Svientsitskii Street, UA-79011 Lviv, Ukraine
We study the ferromagnetic order-disorder phase transition in Ising spin fluids with hard-core Yukawa interaction truncated at various cut-off radii rc. We have performed extensive Monte Carlo simulations in the canonical ensemble at a fixed density, making use of the histogram reweighting technique and finite-size scaling methods. The system sizes range up to 10000 particles.
We focus our interest on the dependence of critical quantities such as the Binder cumulant and various exponent ratios on the value of rc, and on the question whether the Fisher-renormalized exponents expected for these systems can be observed in the simulations. It turns out that the corrections to scaling decaying with a rather small exponent make it impossible to reach the asymptotic region with the limited computational power available. Thus, we observe only effective exponents, with different values depending on the chosen cut-off radius. The same dependence is also found for the critical Binder cumulant obtained with the crossing technique. Nevertheless, a closer investigation of γeff as a function of temperature seems to point towards a Fisher-renormalized asymptotic value.
Supported by the Austrian Fonds zur Förderung der wissenschaftlichen Forschung, project No P18592.