Veranstaltungskalender

We present a first principle treatment of the dynamic structure factor and the spectral density of single-particle excitations for weakly and strongly interacting 2D dipolar systems. The systems of ultracold dysprosium (erbium), polar molecules and indirect excitons are good candidates for experimental validations of our analyses.

Using the path integral Monte Carlo technique in the grand canonical ensemble we evaluated the imaginary-time density response and the one-particle Matsubara Green's function. The stochastic optimization method was used to accurately reconstruct the excitation spectrum. This approach allows one to analyze in detail the temperature-density dependence of the phonon-maxon-roton dispersion, its broadening (damping) and hybridization due to quasiparticle decay processes. In particular, we found that the two-roton state (Pitaevskii "plateau") exists independently of the presence of a condensate and, therefore, conclude that the roton mode has a classical origin due to short-range particle correlations. Its observation in classical liquids is, probably, prevented by the softening and overdamping.

www.iqo.uni-hannover.de

Dr. Alexey Filinov, Christian-Albrechts-Universität zu Kiel, Institut für Theoretische Physik und Astrophysik

Institut für Quantenoptik

Dienstag, 06. November 2012, 10:00 bis 11:00 Uhr

Hauptgebäude (Gebäude 1101, Seminarraum D 326, Institut für Quantenoptik)
Welfengarten 1, 30167 Hannover

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