Kiel 2011 – scientific programme

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P: Fachverband Plasmaphysik

P 18: Poster: Theorie/Simulation dichter und stark gekoppelter Plasmen

P 18.7: Poster

Wednesday, March 30, 2011, 16:30–18:30, Foyer

Structural properties and collective excitations in 2D dipolar gas — •Alexey Filinov and Michael Bonitz — Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität, Leibnizstr. 15, D-24098 Kiel, Germany

We study properties of 2D bosonic gas interacting via dipolar potential. Using path integral Monte Carlo we investigate the equation of state, the density-temperature dependence of the superfluid density, the momentum distribution and the isothermal compressibility. We also evaluate the excitation spectrum, ω(k^→), of the longitudinal density oscillations in several approximations: classical QLCA [1], the density response evaluated using the Lindhard function, the sum-rules formalism [2], the analytical continuation from the imaginary time density correlation function using the stochastic optimization method [3].

From the obtained dispersion relations we analyze the formation in the spectrum of the roton minima and its connection with the normal density of the quasi-particles excitations using the Feynman formula.

[1] K. Golden, G. Kalman, Z. Donko and P. Hartmann, Phys. Rev. B 78, 045304 (2008) [2] F. Dalfovo and S. Stringari, Phys. Rev. B 46, 13991 (1992) [3] A. S. Mishchenko, Lect. Notes Phys. 739, 367 (2008)