Hannover 2016 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 61: Quantum Gases: Fermions II
Q 61.5: Vortrag
Freitag, 4. März 2016, 12:00–12:15, e001
Dynamics of Trapped Dipolar Fermi Gases: From Collisionless to Hydrodynamic Regime — •Vladimir Veljić1, Antun Balaž1, and Axel Pelster2 — 1Scientific Computing Laboratory, Institute of Physics Belgrade, University of Belgrade, Serbia — 2Physics Department and Research Center OPTIMAS, Technical UIniversity of Kaiserslautern, Germany
A recent time-of-flight expansion experiment has now unambiguously detected a Fermi surface deformation in a dipolar quantum gas of fermionic erbium atoms in the collisionless regime [1]. Here we follow Ref. [2] and perform a systematic study of a time-of-flight expansion for trapped dipolar Fermi gases ranging from the collisionless to the hydrodynamic regime at zero temperature. To this end we solve analytically the underlying Boltzmann-Vlasov equation in the vicinity of equilibrium by using a suitable rescaling of the equilibrium distribution [3], where the collision integral is simplified within a relaxation time approximation. We also analyze the quench dynamics, which is induced by a sudden rotation of the polarization of the atomic magnetic moments and show that it can be understood in terms of a superposition of the low-lying collective modes. All presented analytical and numerical calculations are relevant for understanding quantitatively ongoing experiments with ultracold fermionic dipolar atoms.
[1] K. Aikawa, et al., Science 345, 1484 (2014).
[2] F. Wächtler, A. R. P. Lima, and A. Pelster, arXiv:1311.5100.
[3] P. Pedri, D. Guery-Odelin, and S. Stringari, Phys. Rev. A 68, 043608 (2003).