Berlin 2008 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 29: Poster II

DY 29.7: Poster

Donnerstag, 28. Februar 2008, 16:00–18:00, Poster C

Monte Carlo study of the evaporation/condensation transition of Ising droplets — •Micha Wiedenmann, Andreas Nußbaumer, Elmar Bittner, and Wolfhard Janke — Institut für Theoretische Physik, Universität Leipzig, Postfach 100920, 04009 Leipzig

This work builds on recent work of A. Nußbaumer et al. [Europhys. Lett. 75 (2006) 716] and studies the evaporation/condensation transition of Ising droplets in three dimensions. We performed Monte Carlo simulations of the Ising model with nearest-neighbor couplings on a simple cubic lattice with periodic boundary conditions at a fixed magnetization, corresponding to a certain amount v_L of overturned spins. The volume v_d of the largest droplet was measured at constant magnetization employing a flood-fill algorithm. For values of the magnetization m<m_c there exists no droplet in the system and the fraction of overturned spins above the equilibrium magnetization m₀ in the largest droplet λ = v_d/v_L is zero. At m=m_c one half of the overturned spins form a droplet which grows for larger values of the magnetization. This behavior can be compared to analytical results given by Biskup et al. [Europhys. Lett. 60 (2002) 21]. In order to do so we measured the spontaneous magnetization m₀, the magnetic susceptibility χ and the planar surface tension τ (which is a good approximation of a Wulff shaped droplet). Rescaling the magnetization to a dimensionless parameter Δ=Δ(m, χ, τ, m₀), our measured results are in good agreement with the theoretical predictions.