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Q: Quantenoptik und Photonik

Q 31: Poster Fallen und Kühlung

Q 31.8: Poster

Tuesday, March 14, 2006, 16:30–18:30, Labsaal

Molecular dynamics simulation of evaporative cooling in time dependent potentials — •Axel Griesmaier, Jürgen Stuhler, and Tilman Pfau — 5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart

We have developed a fast and effective molecular dynamics simulation of trapped atomic clouds in almost arbitrary time dependent potentials. Using a scaling technique for the atomic properties, we are able to map the evolution of the thermodynamic properties of millions of atoms by simulating only a few hundred particles. The atoms are treated as classical objects which interact solely by simple hard sphere collisions. We have simulated the complete evaporation procedure of our chromium BEC experiment including the transfer from the single beam to the crossed optical dipole trap and compared the results with the experimental data. With only 250 simulated particles, we are able to reproduce the experimental findings with a deviation of only a factor of two in the number of atoms when the phase space density approaches unity. The simulation of the experiment which corresponds to 15s in real time, takes about two hours on a standard up-to-date office PC. We discuss optimal evaporation strategies for crossed optical dipole traps.