QUROPE Quantum Information Processing and Communication in Europe

G. Morigi (P8 USAAR), invited talk, Cavity cooling and crystalline phases of polar molecules

G. Morigi, in collaboration with T. Kampschulte, D. Meschede (P8 USAAR), talk, EIT cooling of a trapped atom in an optical resonator

S. Blum, G. Olivares-Rentería, C. Ottaviani, G. Morigi, H. Rütz, S. Zaske, J. L´huillier, C. Becher (P8 USAAR), poster, Frequency Down-Conversions of Single Photons into Telecom BAnd

G. Morigi (P8 USAAR), invited talk, Quantum linear-zig-zag transition in ultracold atom chains

C. Cormick (P8 USAAR), poster, Dipolar interactions in ultracold ion chains

Structural defects in ion crystals can be formed during a linear quench of the transverse trapping frequency across the mechanical instability from a linear chain to a zigzag structure. The density of defects after the sweep can be conveniently described by the Kibble–Zurek mechanism (KZM). In particular, the number of kinks in the zigzag ordering can be derived from a time-dependent Ginzburg–Landau equation for the order parameter, here the zigzag transverse size, under the assumption that the ions are continuously laser cooled.

We theoretically study the occurrence of quantum jumps in the resonance fluorescence of a trapped atom. Here, the atom is laser cooled in a configuration of level such that the occurrence of a quantum jump is associated to a change of the vibrational center-of-mass motion by one phonon. The statistics of the occurrence of the dark fluorescence period is studied as a function of the physical parameters and the corresponding features in the spectrum of resonance fluorescence are identified.

A string of trapped ions at zero temperature exhibits a structural phase transition to a zigzag structure, tuned by reducing the transverse trap potential or the interparticle distance. The transition is driven by transverse, short wavelength vibrational modes. We argue that this is a quantum phase transition, which can be experimentally realized and probed.

A quasi-one-dimensional system of trapped, repulsively interacting atoms (e.g., an ion chain) exhibits a structural phase transition from a linear chain to a zigzag structure, tuned by reducing the transverse trap potential or increasing the particle density. Since it is a one-dimensional transition, it takes place at zero temperature and therefore quantum fluctuations dominate. In Fishman et al. [ Phys. Rev.

This work theoretically addresses the trapping of an ionized atom with a single valence electron by means of lasers, analyzing qualitatively and quantitatively the consequences of the net charge of the particle. In our model, the coupling between the ion and the electromagnetic field includes the charge monopole and the internal dipole, within a multipolar expansion of the interaction Hamiltonian. Specifically, we perform a Power–Zienau–Woolley transformation, taking into account the motion of the center of mass.