S. Hensler

Bose-Einstein Condensation of Chromium

We report on the generation of a Bose-Einstein condensate in a gas of chromium atoms, which have an exceptionally large magnetic dipole moment and therefore underlie anisotropic long-range interactions. The preparation of the chromium condensate requires novel cooling strategies that are adapted to its special electronic and magnetic properties. The final step to reach quantum degeneracy is forced evaporative cooling of 52Cr atoms within a crossed optical dipole trap. At a critical temperature of T(c) approximately 700 nK, we observe Bose-Einstein condensation by the appearance of a two-component velocity distribution. We are able to produce almost pure condensates with more than 50,000 condensed 52Cr atoms.

Observation of Feshbach Resonances in an Ultracold Gas of 52Cr

We have observed Feshbach resonances in collisions between ultracold 52Cr atoms. This is the first observation of collisional Feshbach resonances in an atomic species with more than one valence electron. The zero nuclear spin of 52Cr and thus the absence of a Fermi-contact interaction leads to regularly spaced resonance sequences. By comparing resonance positions with multichannel scattering calculations we determine the s-wave scattering length of the lowest (2S+1)Sigma(+)(g) potentials to be 112(14) a(0), 58(6) a(0), and -7(20) a(0) for S=6, 4, and 2, respectively, where a(0)=0.0529 nm.

Continuous loading of a magnetic trap

We have realized a scheme for continuous loading of a magnetic trap (MT).

Demagnetization cooling of a gas

{}^{52}\mathrm{Cr}

Determination of the s-wave Scattering Length of Chromium

atoms are continuously captured and cooled in a magneto-optical trap (MOT). Optical pumping to a metastable state decouples atoms from the cooling light. Due to their high magnetic moment

Continuous loading of cold atoms into a Ioffe?Pritchard magnetic trap

(6 {\ensuremath{\mu}}_{B}),

Doppler cooling of an optically dense cloud of magnetically trapped atoms

low-field seeking metastable atoms are trapped in the magnetic quadrupole field provided by the MOT. Limited by inelastic collisions between atoms in the MOT and in the MT, we load

Demagnetization cooling of a Chromium cold gas

{10}^{8}

Observation of Bose-Einstein condensation and Feshbach resonances in a gas of chromium atoms

metastable atoms at a rate of

Collisional properties of a dipolar gas of ultracold chromium atoms

{10}^{8}