Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 18: Membranes and vesicles I (joint BP/CPP)

BP 18.5: Talk

Tuesday, March 17, 2015, 10:45–11:00, H 1028

Using Markov state models to obtain free energies of (de)mixing — •Djurre H. de Jong and Andreas Heuer — University of Münster, Münster, Germany

Obtaining free energies of demixing in multicomponent systems, for example lipid bilayers, would greatly benefit many (theoretical) studies. For such systems the initial state, i.e. the mixed configuration, is often thermodynamically highly unstable. This can render standard techniques like umbrella sampling problematic.

We show that application of Markov state models to several short and independent simulations allows one to extract the free energy gain upon demixing very reliably. Here it is important that the temporal evolution of an appropriately defined order parameter displays local fluctuations. Specifically, this method is applied to a two component Ising model and a binary Lennard-Jones system.