Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 64: Correlated Electrons: Nonequilibrium Quantum Many-Body Systems 1

TT 64.8: Vortrag

Donnerstag, 10. März 2016, 11:30–11:45, H22

Statistical analysis of the flow equation method for intermediate flow parameters — •Nils O. Abeling and Stefan Kehrein — Institut für Theoretische Physik, Göttingen, Germany

The flow equation approach is an RG-like method employing continuous unitary transformations to map an initial Hamiltonian to an effective Hamiltonian which takes on a simple banded form [1]. In our work we study the properties of the effective Hamiltonian for intermediate flow parameters when only off-diagonal matrix elements with large energy differences (as compared to the many-body level spacing) have been eliminated. In this case, we show that the diagonal elements already contain the necessary information for a time evolution until a certain maximum time. The remaining off-diagonal matrix elements can be interpreted as a banded random matrix.

[1] F. Wegner, Ann. Phys. 506, 77 (1994)