"Ultracold ensembles of molecules near quantum degeneracy."

  • Datum: 19.06.2012
  • Uhrzeit: 11:30 - 11:30
  • Vortragende(r): Prof. Dr. Hanns-Christoph Nägerl, Universität Innsbruck; Institute for Experimental Physics
  • Raum: Herbert Walther Lecture Hall
  • Gastgeber: MPQ
"Dipolar quantum gas systems at ultralow temperatures are expected to exhibit novel many-body quantum phases as a result of the long-range and anisotropic dipole-dipole interaction. For our Rb-Cs mixture experiment the focus is on the creation of a bosonic quantum gas of polar ground-state RbCs molecules using Feshbach association and subsequent stimulated adiabatic Raman transfer (STIRAP). We have created a high phase-space density sample of ultracold RbCs Feshbach molecules from an ultracold mixture of Rb and Cs and have performed high-resolution molecular spectroscopy using the Feshbach molecules and have found intermediate electronically excited levels suitable for RbCs ground-state transfer. We have measured the binding energy of the RbCs rovibrational ground state in two-photon spectroscopy and have performed STIRAP experiments with transfer efficiencies of up to 90%. We have implemented an optical lattice with the ultimate aim to create a Mott-insulator state having precisely one atom of each species at each lattice site to improve the creation efficiency for the Feshbach molecules and the STIRAP transfer efficiency. Presently, we switch on the lattice after Feshbach molecule creation to localize the molecules and to prevent collisions. To improve the STIRAP efficiency we have set up ultra-stable optical resonators to which we lock the transfer lasers to reduce laser phase noise. Finally, we will give an update on our endeavor to create a BEC of ground-state Cs dimers."
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