Erlangen 2018 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 27: Quantum Gases (Bosons) III
Q 27.1: Vortrag
Montag, 5. März 2018, 16:15–16:30, K 2.020
Dimensional Crossover in a Bosonic Quantum Gas — •Polina Matveeva, Denis Morath, Dominik Strassel, Axel Pelster, Imke Schneider, and Sebastian Eggert — Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, Germany
From the Mermin-Wagner theorem it follows that there is no Bose-condensation in 1D at any finite temperature. Therefore one can ask the question about new critical exponents, that emerge when the 1D-3D crossover is studied in context of 3D anisotropic bosons on a lattice. Our model is represented by 1D tubes with hopping between them, which can be simulated in experiments with optical lattices [1]. Tuning the hopping between the tubes allows us to drive our system continuously from 1D to 3D. Here we determine the exponent, that appears for Tc, when it increases from zero as a function of inter-chain hopping [2]. To this end we use an effective potential approach to calculate the Landau potential and to derive critical parameters of the system as a function of inter-chain hopping, which we take into account perturbatively. We perform calculations both for non-interacting bosons in tubes and also for interacting bosons with infinite on-site repulsion and nearest neighbor density-density interaction. In the latter case these interactions are taken into account using the bosonization technique. We also compare our results with numerical results for the critical exponent, obtained from extensive Quantum Monte-Carlo simulations.
[1] A. Vogler et al., Phys. Rev. Lett. 113, 215301 (2014)
[2] B. Irsigler and A. Pelster, Phys. Rev. A 95, 043610 (2017)