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A quantum communication node with high quality quantum memories and photonic interfaces capable of quantum logic operations provide a technology platform for realizing quantum repeaters. We will discuss a viable implementation in trapped ion systems.

We present a scalable approach to quantum information processing utilizing trapped ions and photons. Ions trapped in microfabricated surface traps provide a practical platform for realizing quantum networks of distributed computing nodes and quantum repeaters.

We propose a novel qubit state measurement method for photonic frequency qubits using a Mach-Zehnder interferometer with unequal path lengths. A practical implementation for photons generated by 171Yb+ ions in a surface trap is described.

We demonstrate direct evaporative cooling of $^{87}$Rb atoms confined in a dimple trap produced by an atom chip. By changing the two chip currents and two external bias fields, we show theoretically that the trap depth can be lowered in a controlled way with no change in the trap frequencies or the value of the field at the trap center. Experimentally, we maximized the decrease in trap depth by allowing some loosening of the trap. In total, we reduced the trap depth by a factor of 20. The geometric mean of the trap frequencies was reduced by less than a factor of 6. The measured phase space density in the final two stages increased by more than two orders of magnitude, and we estimate an increase of four orders of magnitude over the entire sequence. A subsequent rf evaporative sweep of only a few megahertz produced Bose-Einstein condensates. We also produce condensates in which raising the trap bottom pushes hotter atoms into an rf "knife" operating at a fixed frequency of 5\,MHz., Comment: 5 pages, 3 figures

We present a compact, transportable system that produces Bose-Einstein condensates (BECs) near the surface of an integrated atom microchip. The system occupies a volume of 0.4 m^3 and operates at a repetition rate as high as 0.3 Hz. Evaporative cooling in a chip trap with trap frequencies of several kHz leads to nearly pure condensates containing 1.9x10^4 87Rb atoms. Partial condensates are observed at a temperature of 1.58(8) \mu K, close to the theoretical transition temperature of 1.1 \mu K., Comment: 3 pages, 4 figures

We discuss a practical scheme to implement memory-assisted measurement-device-independent quantum key distribution protocol using trapped ion systems with the potential to extend the range of conventional QKD by a factor of 2.