Hybrid Atom--Photon Quantum Gate in a Superconducting Microwave Resonator

We propose a novel hybrid quantum gate between an atom and a microwave photon in a superconducting coplanar waveguide cavity by exploiting the strong resonant microwave coupling between adjacent Rydberg states. Using experimentally achievable parameters gate fidelities $> 0.99$ are possible on sub-$\mu$s timescales for waveguide temperatures below 40 mK. This provides a mechanism for generating entanglement between two disparate quantum systems and represents an important step in the creation of a hybrid quantum interface applicable for both quantum simulation and quantum information processing.Comment: 4 pages, 4 figure

Oxygen isotopic and petrological constraints on the origin and relationship of IIE iron meteorites and H chondrites

New oxygen isotopic measurements of IIEs and H chondrites are indistinguishable — strengthening a possible common origin for these groups. Combining oxygen results with mineralogy, the nature of their parent body or bodies can be explored

A fast edge charge exchange recombination spectroscopy system at the ASDEX Upgrade tokamak

In this work, a new type of high through-put Czerny-Turner spectrometer has been developed which allows us to acquire multiple channels simultaneously with a repetition time on the order of 10 μ s at different wavelengths. The spectrometer has been coupled to the edge charge exchange recom- bination system at ASDEX Upgrade which has been recently refurbished with new lines of sight. Construction features, calibration methods, and initial measurements obtained with the new setup will be presented.European Commission (EUROfusion 633053

Magnetism in SQUIDs at Millikelvin Temperatures

We have characterized the temperature dependence of the flux threading dc SQUIDs cooled to millikelvin temperatures. The flux increases as 1/T as temperature is lowered; moreover, the flux change is proportional to the density of trapped vortices. The data is compatible with the thermal polarization of surface spins in the trapped fields of the vortices. In the absence of trapped flux, we observe evidence of spin-glass freezing at low temperature. These results suggest an explanation for the "universal" 1/f flux noise in SQUIDs and superconducting qubits.Comment: 4 pages, 4 figure

Further analysis of the BFKL equation with momentum cutoffs

In this paper we investigate the effect of introducing transverse momentum cutoffs on the BFKL equation. We present solutions in moment space for various models of the BFKL kernel for different combinations of these cutoffs. We improve on previous calculations by using the full BFKL kernel (rather than simplified analytic approximations). The significance of the next-to-leading or ``higher twist'' terms in the kernel are assessed. We find that, while these terms are negligible in the absence of cutoffs, introducing an infra-red cutoff markedly enhances their significance.Comment: 27 pages, latex, 6 figure

Optimized Coplanar Waveguide Resonators for a Superconductor-Atom Interface

We describe the design and characterization of superconducting coplanar waveguide cavities tailored to facilitate strong coupling between superconducting quantum circuits and single trapped Rydberg atoms. For initial superconductor-atom experiments at 4.2 K, we show that resonator quality factors above $10^4$ can be readily achieved. Furthermore, we demonstrate that the incorporation of thick-film copper electrodes at a voltage antinode of the resonator provides a route to enhance the zero-point electric fields of the resonator in a trapping region that is 40 $\mu$m above the chip surface, thereby minimizing chip heating from scattered trap light. The combination of high resonator quality factor and strong electric dipole coupling between the resonator and the atom should make it possible to achieve the strong coupling limit of cavity quantum electrodynamics with this system.Comment: 4 pages, 4 figure

Low x saturation at HERA ?

We compare the predictions of two distinct dipole models for inclusive and exclusive diffractive processes. While only one of these dipole models contains perturbative saturation dynamics, we show that the predictions of both models are fully consistent with the available HERA data, indicating no compelling evidence for saturation at present HERA energies.Comment: 8 pages, 4 figures, presented at the 26th Montreal-Rochester-Syracuse-Toronto (MRST) conference held at Concordia University, Montreal, Canada, 12th-14th May 2004. To appear in the proceeding