Hamburg 2009 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 38: Quantengase: Gemische

Q 38.4: Vortrag

Mittwoch, 4. März 2009, 17:15–17:30, VMP 6 HS-A

Interaction dependent adiabatic heating of Bose-Fermi mixtures in optical lattices — •Marcus Cramer — Imperial College London, UK

In recent experiments with Bose-Fermi mixtures in optical lattices a decrease in bosonic coherence as compared to the purely bosonic case has been observed [1-3]. This effect has been attributed to adiabatic heating [4] and to a renormalization of interaction and tunneling amplitudes [5]. Here, we investigate in detail the role of the inter-species interaction in the adiabatic heating process and determine the final temperature of the mixture in the lattice. Within a Hartree-Fock-Bogoliuobov mean-field approach, we are able to treat the full three dimensional situation including the (anisotropic) harmonic confinement. We find remarkable qualitative agreement between the obtained increase in temperature and the recently observed decrease of coherence as a function of the Bose-Fermi interaction [3], suggesting that temperature effects could be one of the main causes for the loss of coherence.
[1] S. Ospelkaus et al., Phys. Rev. Lett. 96, 180403 (2006).

[2] K. Günter et al., Phys. Rev. Lett. 96, 180402 (2006).

[3] Th. Best et al., arXiv:0807.4504.

[4] M. Cramer et al., Phys. Rev. Lett. 100, 140409 (2008).

[5] D.-S. Lühmann et al., Phys. Rev. Lett. 101, 050402 (2008).