159 research outputs found
Correlations and Counting Statistics of an Atom Laser
We demonstrate time-resolved counting of single atoms extracted from a weakly
interacting Bose-Einstein condensate of Rb atoms. The atoms are detected
with a high-finesse optical cavity and single atom transits are identified. An
atom laser beam is formed by continuously output coupling atoms from the
Bose-Einstein condensate. We investigate the full counting statistics of this
beam and measure its second order correlation function in a
Hanbury Brown and Twiss type experiment. For the monoenergetic atom laser we
observe a constant correlation function and an atom
number distribution close to a Poissonian statistics. A pseudo-thermal atomic
beam shows a bunching behavior and a Bose distributed counting statistics
Cold atoms in cavity-generated dynamical optical potentials
We review state-of-the-art theory and experiment of the motion of cold and
ultracold atoms coupled to the radiation field within a high-finesse optical
resonator in the dispersive regime of the atom-field interaction with small
internal excitation. The optical dipole force on the atoms together with the
back-action of atomic motion onto the light field gives rise to a complex
nonlinear coupled dynamics. As the resonator constitutes an open driven and
damped system, the dynamics is non-conservative and in general enables cooling
and confining the motion of polarizable particles. In addition, the emitted
cavity field allows for real-time monitoring of the particle's position with
minimal perturbation up to sub-wavelength accuracy. For many-body systems, the
resonator field mediates controllable long-range atom-atom interactions, which
set the stage for collective phenomena. Besides correlated motion of distant
particles, one finds critical behavior and non-equilibrium phase transitions
between states of different atomic order in conjunction with superradiant light
scattering. Quantum degenerate gases inside optical resonators can be used to
emulate opto-mechanics as well as novel quantum phases like supersolids and
spin glasses. Non-equilibrium quantum phase transitions, as predicted by e.g.
the Dicke Hamiltonian, can be controlled and explored in real-time via
monitoring the cavity field. In combination with optical lattices, the cavity
field can be utilized for non-destructive probing Hubbard physics and tailoring
long-range interactions for ultracold quantum systems.Comment: 55 page review pape
Molecules of Fermionic Atoms in an Optical Lattice
We create molecules from fermionic atoms in a three-dimensional optical
lattice using a Feshbach resonance. In the limit of low tunnelling, the
individual wells can be regarded as independent three-dimensional harmonic
oscillators. The measured binding energies for varying scattering length agree
excellently with the theoretical prediction for two interacting atoms in a
harmonic oscillator. We demonstrate that the formation of molecules can be used
to measure the occupancy of the lattice and perform thermometry.Comment: 4 page
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