Dresden 2003 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 7: Computational Physics
CPP 7.3: Talk
Tuesday, March 25, 2003, 17:30–17:45, ZEU/160
Energy Density of Heteropolymers — •Michael Bachmann and Wolfhard Janke — Institut für Theoretische Physik, Universität Leipzig, Augustusplatz 10/11, 04109 Leipzig
We use the random walk Monte Carlo (MC) algorithm of Wang and Landau [1]
to calculate the energy density of lattice proteins that fold under
the influence of the nearest-neighbor interactions between the
hydrohobic residues as regarded in the simple HP model [2]. The
advantage
of this method, which has originally been applied for simulating spin
systems,
is that it produces a locally flat histogram without
introducing a temperature. Therefore a random walk through the
energy space yields a very accurate estimate for the density of
states which allows a calculation of all energy-dependent
thermodynamic quantities. Thus, in contrast to conventional MC
simulations, the free energy and the entropy can directly be determined.
We compare our results with such from exact enumerations for short
chain lengths as well as with results obtained with other MC techniques
for longer sequences.
[1] F. Wang and D.P. Landau, Phys. Rev. Lett. 86, 2050
(2001).
[2] K.F. Lau and K.A. Dill, Macromolecules 22, 3986 (1989).