Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 25: Quantum Liquids, Bose-Einstein Condensates, Ultracold Atoms, ...

TT 25.5: Vortrag

Donnerstag, 29. März 2007, 15:00–15:15, H18

Superfluidity in small 2D trapped systems of charged bosons — •Jens Böning, Alexei Filinov, and Michael Bonitz — Christian-Albrechts Universität Kiel, Institut für Theoretische Physik und Astrophysik, Leibnizstraße 15, 24098 Kiel, Germany

Superfluidity in a trapped cloud of quantum particles is defined using the cloud’s response to a rotation of the external potential. The effect is known as the Hess-Fairbank or non classical moment of inertia (NCRI) effect and corresponds to the Meissner effect for superconductivity. It originates from the impossibility to excite vortices in macroscopic systems with an accoustic phonon like energy spectrum and is, thus, inseperably connected to inter-particle interactions. However, due to the discrete nature of the spectrum in trapped finite systems, the NCRI effect can be observed in quantum systems in any case regardless of the presense of interactions. We investigate small bosonic systems in order to distinguish between effects related to a finite system size, inter-particle interactions and quantum statistics. Our results are obtained with first principle path-integral Monte-Carlo (PIMC) simulations [1] and are compared to analytical expressions for the ideal case based on permutations cycles [2], respectively.

[1] Michael Bonitz and Dirk Semkat (eds.): Introduction to Computational Methods in Many Body Physics, Rinton Press Inc., 2006

[2] J. Schneider and H. Wallis: Fully quantum mechanical moment of inertia of a mesoscopic Bose gas Eur. Phys. J. B 18, 507–512, 2000