Hannover 2013 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 35: Poster I

Q 35.65: Poster

Tuesday, March 19, 2013, 16:00–18:30, Empore Lichthof

Ray tracing for matter-waves — •Mathias Schneider and Reinhold Walser — Institut für Angewandte Physik, TU Darmstadt

The development of quantum limited acceleration and rotation devices is a key research direction. In the context of ultra-cold matter-waves, whether thermal clouds or Bose-Einstein condensates, this is usually realized with interferometers. The design of high precision optical devices, in particular optical interferometers, does not rely on the full Maxwell's equations but only on efficient semi-classical ray tracing methods. In the same spirit, we approximate the dynamics interacting thermal clouds or Bose-Einstein condensates with a ray tracing formalism that is very suited for realistic experimental setups. We employ the effective single-particle Wigner function as a phase-space representation of the atom cloud. A major virtue of this formulation is that, once the distribution is known for the initial state, it can be calculated at arbitrary times by merely propagating its values along the phase-space flow. The trajectories comprising this flow can be considered the matter-wave rays. In addition to this ray aspect, the phase-space formulation leads to a simple approximation scheme for the interacting stationary state at finite temperature. This Lambert-approximation interpolates between the Thomas-Fermi approximation of strongly interacting gases and the Maxwell-Boltzmann distribution for ideal gases.