T. Bergeman

Dark resonances for ground-state transfer of molecular quantum gases

One possible way to produce ultra-cold, high-phase-space-density quantum gases of molecules in the rovibronic ground state is given by molecule association from quantum-degenerate atomic gases on a Feshbach resonance and subsequent coherent optical multi-photon transfer into the rovibronic ground state. In ultra-cold samples of Cs2 molecules, we observe two-photon dark resonances that connect the intermediate rovibrational level |v=73,J=2〉 with the rovibrational ground state |v=0,J=0〉 of the singlet X1Σg+ ground-state potential. For precise dark resonance spectroscopy we exploit the fact that it is possible to efficiently populate the level |v=73,J=2〉 by two-photon transfer from the dissociation threshold with the stimulated Raman adiabatic passage (STIRAP) technique. We find that at least one of the two-photon resonances is sufficiently strong to allow future implementation of coherent STIRAP transfer of a molecular quantum gas to the rovibrational ground state |v=0,J=0〉.

Bose condensates in a harmonic trap near the critical temperature

The mean-field properties of finite-temperature Bose-Einstein gases confined in spherically symmetric harmonic traps are surveyed numerically. The solutions of the Gross-Pitaevskii (GP) and Hartree-Fock-Bogoliubov (HFB) equations for the condensate and low-lying quasiparticle excitations are calculated self-consistently using the discrete variable representation, while the most high-lying states are obtained with a local-density approximation. Consistency of the theory for temperatures through the Bose condensation point

Quantum-beat spectroscopy of the A 2 Σ + state of the OH free radical

{T}_{c}

Breakdown of scale invariance in the vicinity of the Tonks-Girardeau limit

requires that the thermodynamic chemical potential differ from the eigenvalue of the GP equation; the appropriate modifications lead to results that are continuous as a function of the particle interactions. The HFB equations are made gapless either by invoking the Popov approximation or by renormalizing the particle interactions. The latter approach effectively reduces the strength of the effective scattering length

Superfluid Bloch dynamics in an incommensurate optical lattice

{a}_{\mathrm{sc}},

Laser Cooling with Intense Laser Fields

increases the number of condensate atoms at each temperature, and raises the value of

ABSOLUTE CALIBRATION OF ELECTRIC FIELDS USING STARK SPECTROSCOPY

{T}_{c}

Magnetostatic trapping fields for neutral atoms.

relative to the Popov approximation. The renormalization effect increases approximately with the log of the atom number, and is most pronounced at temperatures near

Gross-Pitaevskii equation for Bose particles in a double-well potential : Two-mode models and beyond

{T}_{c}.

Analysis of strongly coupled electronic states in diatomic molecules: Low-lying excited states of RbCs

Comparisons with the results of quantum Monte Carlo calculations and various local-density approximations are presented, and experimental consequences are discussed.