Dresden 2006 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 50: Lattice Dynamics and Non-Linear Excitations
DY 50.1: Vortrag
Freitag, 31. März 2006, 10:15–10:30, H\"UL 186
Continuous time quantum Monte-Carlo simulations of polarons and bipolarons — •J.P. Hague1, P.E. Kornilovitch2, A.S. Alexandrov1, and J.H. Samson1 — 1Dept. of Physics, Loughborough University, LE11 3TU, UK — 2Hewlett-Packard Company, 1000 NE Circle Blvd, Corvallis, Oregon 97330, USA
We present the results of a continuous-time quantum Monte-Carlo algorithm for simulating polarons and bipolarons. An exact integration over phonon degrees of freedom leads to an efficient algorithm, which may be used for arbitrary interaction range. We consider the effects of lattice geometry and dimensionality on polaron properties including the effective mass, energy, number of phonons involved in the polaron, mass isotope coefficient, polaron spectrum and polaron density of states. In particular, we find that the coordination number has a greater effect on the polaron dynamics than the dimensionality, and that long-range Fröhlich interactions wash-out the effects of the lattice geometry (cond-mat/0509590). Finally, we discuss extensions of the algorithm to simulate bipolarons on various lattice configurations (e.g. the staggered ladder).