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Humboldt-Universität zu Berlin - Mathematisch-Naturwissen­schaft­liche Fakultät - Nanooptik

Strong interactions in optical lattices

Dr. Servaas Kokkelmans
Was
  • Optik/Photonik Kolloquium
Wann 11.06.2009 von 14:00 bis 15:00 (Europe/Berlin / UTC200) iCal
Wo Hausvogteiplatz 5-7, Raum 109

Eindhoven University of Technology<br />
Netherlands<br />
<br />
Optical lattices allow for a large amount of control over the physical
parameters of the confined atoms. In a deep lattice, one, two or even more
particles can be trapped on a single site. Using a Feshbach resonance, the
atoms can be made strongly interacting by tuning a magnetic field, while the
depth and geometry of the lattice can be adjusted via the laser field. A
lattice allows also for high-precision measurements: for instance, in the
group of Immanuel Bloch very accurate values for relative scattering lengths
of rubidium could be derived by studying coherent collisional spin dynamics.
These high precision measurements provide challenges for the theoretical
description of interacting atoms.<br />
The Bloch experiment indicated at a discrepancy with state-of-the-art
rubidium interaction properties. This triggered us to formulate an
alternative model for two interacting atoms in an optical lattice,
suitable for high-precision measurements and strong interactions.
In our model we treat the interactions exactly, while we describe the
lattice in a perturbative way.<br />
We also investigated the possibility to stabilize Efimov trimers in optical
lattices. These trimers can be formed only if the two-body interaction is
sufficiently resonant. We present universal solutions of three bosons in a
harmonic potential, for all ranges of the scattering length and harmonic
oscillator length. The combination of being able to tune both length
parameters gives rise to quite distinct solutions of these trimers, and
allows for minimizing the inelastic losses.