Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 32: Correlated Electrons: Poster Session

TT 32.38: Poster

Donnerstag, 28. Februar 2008, 14:00–18:00, Poster B

Quantum Monte Carlo Simulations in Continuous Time: An Application to the Hubbard Model — •Sebastian Fuchs and Thomas Pruschke — Institut für Theoretische Physik, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen

We perform quantum Monte Carlo simulations of the Hubbard model using the Dynamical Cluster Approximation (DCA) [1]. Hereby the complexity of the full lattice problem is reduced by mapping it to a finite size cluster self-consistently embedded in a mean-field. The resulting cluster problem is solved by a Monte Carlo procedure using a weak coupling expansion in continuous imaginary time [2]. Compared to the traditional Hirsch-Fye algorithm simulations can be much more efficient and systematical errors due to a discretization of the imaginary time axis are avoided.

Our main focus is the investigation of the single-particle properties of the Hubbard model in the antiferromagnetic phase. Using analytic continuation of the Monte Carlo data the DCA permits us to calculate spectral functions with explicit k-dependence.

Our implementation of the algorithm is based on the libraries of the ALPS project [3]. ALPS is an open source effort providing libraries and simulation codes for strongly correlated quantum mechanical systems.

[1] Th. Maier et. al., Rev. Mod. Phys. 77, 1027 (2005)

[2] A. N. Rubstov et. al., Phys. Rev. B 72, 035122 (2005)

[3] http://alps.comp-phys.org