Münster 1999 – wissenschaftliches Programm

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SYMC: Symposium Neue Entwicklungen in Quanten-Monte-Carlo-Simulationen

SYMC IV: HV IV

SYMC IV.1: Hauptvortrag

Mittwoch, 24. März 1999, 17:00–17:30, Ger

Hole dynamics in one and two-dimensional Mott insulators: a quantum Monte Carlo study. — •Fakher Assaad — Institut f"ur Theoretische Physik III, Universit"at Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart

We present a generalization of the projector quantum Monte Carlo algorithm to compute zero temperature imaginary time correlation functions in a numerically stable way. To demonstrate the efficiency of this algorithm we extract the quasiparticle weight, Z(k^→), from the long imaginary time behavior of the single particle Green function. In the special case of a single hole in the half-filled one-dimensional Hubbard model, our results are consistent with Z(k_f^→) ∼ 1/√L with L the lattice length. >From the imaginary time data, we obtain dynamical properties with the use of the Maximum Entropy method. In one dimension, we concentrate on the signature of spin-charge separation on the spectral function A(k^→,ω). In two-dimensions, we discuss the anomalous behavior of charge dynamics and the related occurrence of flat bands around the (0,± π), (± π,0) points in the Brillouin zone when holes are doped in the Mott insulating state.