Stuttgart 2012 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 26: Poster: Atomic systems in external fields
A 26.13: Poster
Mittwoch, 14. März 2012, 16:30–19:00, Poster.V
Breathing modes in harmonically confined quantum systems — •David Hochstuhl1, Jan-Willem Abraham1, Chris McDonald2, Thomas Brabec2, and Michael Bonitz1 — 1Christian-Albrechts-Universität Kiel — 2University of Ottawa
The Breathing Mode (BM), collective oscillations induced by monopole excitations, constitutes a versatile tool for the characterization of many-particle systems as, e.g., Bose-Einstein condensates, nuclear matter or quantum dots. It has been thoroughly investigated in classical Coulomb systems [1], where it shows a universal, particle-number independent frequency of ω=√3 (in units of the harmonic trap frequency). For BMs in quantum systems, due to the non-locality of the wavefunctions, a different picture arises: the classical frequency is recovered only in the Wigner-cristallization regime. On the other hand, in the ideal quantum limit of weakly interacting systems, the BM frequency approaches ω=2. These two extrema are well known and can be conveniently handled by perturbation theory.
Our focus here is on the intermediate region. Therefore, we solve the Schrödinger equation for systems consisting up to 12 particles, trapped in a two-dimensional parabolic potential, and determine their BM frequencies with respect to the particle interaction strength. For the solution, we apply the Multiconfigurational time-depedent Hartree-Fock method as well as a restricted active-space variant of the Configuration Interaction method.
[1] C. Henning, et al., Phys. Rev. Lett. 101 045002 (2008) [2] S. Bauch, et al., Phys. Rev. B 80 054515 (2009)