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TT: Fachverband Tiefe Temperaturen
TT 44: Focus Session: Frontiers of Electronic Structure Theory - Non-Equilibrium Phenomena at the Nano-Scale III (organized by O)
TT 44.1: Topical Talk
Dienstag, 1. April 2014, 10:30–11:00, TRE Ma
Ultrafast relaxation dynamics of Hubbard nanoclusters — •Michael Bonitz1, Sebastian Hermanns1, Christopher Hinz1, and Denis Lacroix2 — 1Institut für Theoretische Physik und Astrophysk, CAU Kiel, Leibnizstr. 15, 24098 Kiel — 2IPN Orsay, 15 Rue Georges Clemenceau, 91406 Orsay
With the growing availability of intense short-pulse radiation sources it becomes possible to drive interacting many-particle or few-particle systems out of equilibrium in a controlled way. The subsequent relaxation and equilibration dynamics is still poorly understood. From a theory point of view these processes are complicated due to the simultaneous dynamics of the occupation functions and of binary correlations. The problem becomes even more complicated when the system has finite size and is spatially inhomogeneous [1]. The Hubbard model is a prototype for treating correlation effects in condensed matter or molecular systems fully including finite size and inhomogeneity effects. We, therefore, concentrate on the relaxation dynamics of small 1D, 2D and 3D Hubbard clusters that contain from a few to several hundred electrons. We observe a complex multi-stage relaxation behavior that depends on the external excitation, on the coupling strength and on the geometry of the system. In this talk we present results from two complementary theoretical approaches: first, from nonequilibrium Green functions where we apply the Generalized Kadanoff Baym ansatz [1] and, second, from a stochastic mean field approach.
[1] K. Balzer, and M. Bonitz, “Nonequilibrium Green’s Functions Approach to Inhomogeneous Systems”, Lect. Notes Phys. 867 (2013)