Macromolecular Quantum Interference Vienna Arndt, Hornberger and Zeilinger provide a summary of recent progress in matter-wave interferometry, outlining near-term experimental objectives as well as theoretical developments towards understanding the mechanisms of decoherence. "In our view, matter-wave interferometry should be feasible for large objects such as proteins, small viruses and nanocrystals with atomic masses of up to 10^6 units. Extrapolating our results to bigger masses and higher temperatures, we believe that neither collisions nor thermal decoherence will be a problem in these cases. No fundamental limit of quantum interference is yet in sight, but much work still has to be done to prepare and manipulate coherent beams of supermassive particles. Carrying out such experiments will be a fascinating challenge."

DARPA Quantum Network Harvard/Boston/BBN Chip Elliot reports on the current status of the DARPA Quantum Network, in continuous operation since June 2004. "The DARPA Quantum Network is the world's first quantum cryptography network, and perhaps also the first QKD system providing continuous operation across a metropolitan area. Four more nodes are now being added to bring the total to 10 QKD nodes." This paper updates quant-ph 0412029 for the upcoming SPIE conference.

Quantum Interference in Time PhysicsWeb, Slashdot Paulus and colleagues have conducted a novel version of the double slit experiment, observing interference fringes with electrons passing through a double slit in time. Separated by femtosecond laser pulses, the 'slit' is composed of two maxima and one minima of the electric field. Slashdot notes several related articles on Zeilinger's interference experiments with fullerenes and biomolecules; see also the "delayed-choice quantum eraser" experiment by Shih and Kim.

Schwab comments on Phys. Rev. Lett. 94, 030402 (2005) arXiv In reply to the recent Gaidarzhy et al. report on "Evidence for Quantized Displacement in Macroscopic Nanomechanical Oscillators," Schwab et al. contend that the Letter contains order-of-magnitude omissions and inaccuracies counter to any interpretation of quantized macroscopic displacement: " ... the evidence, analysis, claims, and conclusions presented are contrary to expectations from fundamentals of quantum mechanics and elasticity theory, and [...] the method used by the authors is unsuitable in principle to observe the quantized energy states of a nanomechanical structure."

Simultaneous State Measurement of Coupled Josephson Phase Qubits NIST, UCSB In Science [25 Feb 2005], McDermott et al. report on simultaneous precision measurement of antiphase oscillation between flux qubits, consistent with entanglement of the two qubit states. "One of the many challenges of building a scalable quantum computer is single-shot measurement of all the quantum bits. Here, we exploit the simultaneous single-shot measurement of two coupled Josephson phase qubits to directly probe interaction of the qubits in the time domain [...] thereby opening the possibility for the full characterization of multi-qubit gates and elementary quantum algorithms."

Quantum Leap canada.com A brief overview of the history and development of quantum cryptography, from its origins through a chance encounter between Charles Bennett and Giles Brassard while swimming in the warm tropical waters of the Caribbean, to the next-generation satellite-based quantum encryption links of tomorrow. "Together, Brassard and Bennett would go on to found a field of science - quantum information processing - whose effects on society some say could even rival the impact that the steam engine had in its time."