QUROPE Quantum Information Processing and Communication in Europe

We introduce lossless state detection of trapped neutral atoms based on cavity-enhanced fluorescence. In an experiment with a single 87-Rb atom, a hyperfine-state detection fidelity of 99.4% is achieved in 85 microseconds. The quantum bit is interrogated many hundred times without loss of the atom while a result is obtained in every read-out attempt. The fidelity proves robust against atomic frequency shifts induced by the trapping potential.

We examine two dimensional mixture of single-component fermions and dipolar bosons. We calculate the self-enregies of the fermions in the normal state and the Cooper pair channel by including first order vertex correction to derive a modified Eliashberg equation. We predict appearance of superfluids with various non-standard pairing symmetries at experimentally feasible transition temperatures within the strong-coupling limit of the Eliashberg equation. Excitations in these superfluids are anyonic and follow non-Abelian statistics.

Physicists in the US (including AQUTE physicist C. Monroe) have used an optical "frequency comb" to reliably entangle a pair of atomic qubits. The breakthrough bodes well for practicable quantum computing because it allows for simpler manipulation of quantum states than in previous systems.

Physicists in Germany and France (including AQUTE members Theodor W. Hänsch, Jakob Reichel, and Philipp Treutlein) have coupled a Bose–Einstein condensate (BEC) of ultracold atoms to the vibrations of a mechanical oscillator for the first time.

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An international team of physicists (involving physicists C. Monroe and A. Acin from the AQUTE and Q-ESSENCE projects respectively) has created the first system that can produce verifiably random numbers. The technique relies on the inherent uncertainties in quantum mechanics and future versions could help cryptographers to encode information more securely than ever before.

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quantum optics, atomic physics, nonlinear dynamics, statistical physics, quantum field theory, many body systems, disordered systems, neural networks, quantum information, foundations of quantum mechanics

ultracold atomic and molecular quantum gases

Quantum optics, single atom trapping, quantum information processing, quantum entanglement of trapped particles, single photon source, quantum cryptography, continuous variables, quantum nondemolition measurements, quantum noise

atom chips, fiber resonators, coherence, Bose-Einstein condensation, BEC