QUROPE Quantum Information Processing and Communication in Europe

We study a system of three trapped ions in an anisotropic bidimensional trap. By focusing on the transverse modes of the ions, we show that the mutual ion-ion Coulomb interactions set entanglement of a genuine tripartite nature, to some extent persistent to the thermal nature of the vibronic modes. We tackle this issue by addressing a nonlocality test in the phase space of the ionic system and quantifying the genuine residual tripartite entanglement in the continuous variable state of the transverse modes.

Light scattering by a periodic atomic array is studied when the atoms couple with the mode of a high-finesse optical resonator and are driven by a laser. When the von-Laue condition is not satisfied, there is no coherent emission into the cavity mode, and the latter is pumped via inelastic scattering processes. We consider this situation and identify conditions for which different nonlinear optical processes can occur.

The efficiency of cavity sideband cooling of trapped molecules is theoretically investigated for the case in which the infrared transition between two rovibrational states is used as a cycling transition. The molecules are assumed to be trapped either by a radiofrequency or optical trapping potential, depending on whether they are charged or neutral, and confined inside a high-finesse optical resonator that enhances radiative emission into the cavity mode.

A theoretical approach is described for an exact numerical treatment of a pair of ultracold atoms interacting via a central potential that are trapped in a finite three-dimensional optical lattice. The coupling of center-of-mass and relative-motion coordinates is treated using an exact diagonalization (configuration-interaction) approach. The orthorhombic symmetry of an optical lattice with three different but orthogonal lattice vectors is explicitly considered as is the Fermionic or Bosonic symmetry in the case of indistinguishable particles.

A cooling scheme for trapped atoms is proposed, which combines cavity-enhanced scattering and electromagnetically induced transparency. The cooling dynamics exploits a three-photon resonance, which combines laser and cavity excitations. It is shown that relatively fast ground-state cooling can be achieved in the Lamb-Dicke regime and for large cooperativity. Efficient ground-state cooling is found for parameters of ongoing experiments.

C. Vo (P3b MPQ), poster, Remote entanglement between a single Atom and a Bose Einstein condensate

C. Hahn (P3b MPQ), poster, Remote Entanglement of a Single Atom and a Bose-Einstein Condensate

M. Koch (P3b MPQ), poster, Observation of time-dependent, third-order photon correlations in cavity QED

S. Baur (P3b MPQ), poster, Remote entanglement between a single Atom and a Bose Einstein condensate

A. Neuzner (P3b MPQ), poster, Coherent shaping of photons using electromagnetically induced transparency

S. Ritter (P3b MPQ), poster, A single-atom optical quantum memory

C. Sames (P3b MPQ), poster, Feedback cooling of a single neutral atom

T. Kampschulte (P6 UBONN), talk, Control of refractive index and motion of a single atom by quantum interference