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TT: Fachverband Tiefe Temperaturen

TT 79: Correlated Electrons - Poster Session

TT 79.66: Poster

Mittwoch, 2. April 2014, 15:00–19:00, P2

Green functions approach to Hubbard nano-clusters with the GKBA and T-matrix approximation — •Niclas Schlünzen, Sebastian Hermanns, and Michael Bonitz — ITAP, Christian-Albrechts-Universität Kiel, Leibnizstraße 15, 24098 Kiel

The Hubbard model describes narrow-band solid state systems in terms of sites, on which the electrons can interact, and hopping amplitudes between these sites. It exhibits the quantum characteristics of solids and recently can also be experimentally realized in finite systems, e.g., ultracold atoms in optical lattices. To describe the out-of-equilibrium dynamics of those systems, the theoretical framework of non-equilibrium Green functions is well suited [1]. It provides a controlled way to apply different many-body approximations. The equations of motion for the Green function can be solved very efficiently by using the generalized Kadanoff–Baym ansatz (GKBA), which has shown accurate results for weak coupling [2]. To describe strongly interacting systems, the T-matrix many-body approximation is a convenient choice [3]. In this contribution, we show first benchmark results for the non-equilibrium dynamics of Hubbard nano-clusters with T-matrix+GKBA comparing them with exact solutions as well as results from different many-body approximations.
[1] K. Balzer, and M. Bonitz, Nonequilibrium Green’s Functions Approach to Inhomogeneous Systems, Springer (2013)
[2] K. Balzer et al., J. Phys. Conf. Ser. 427, 012006 (2013)
[3] M. Puig von Friesen et al., Phys. Rev. Lett. 103, 17 (2009)