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."
Schrodinger's Kittens Mohanty Group In Physical Review Letters [ 28 Jan 2005 ], the Mohanty Group at Boston University reports evidence of [center-of-mass displacement] quantum nanomechanical oscillations in silicon antennae of ~ 50 billion atoms, making this the largest observation of quantum mechanical behavior to date. "It's a truly macroscopic quantum system," says Alexei Gaidarzhy, the paper's lead author and a graduate student in the BU College of Engineering's Department of Aerospace and Mechanical Engineering. "When it's a new phenomenon, it's best not to be guided by expectations based on conventional wisdom. The philosophy here is to let the data speak for itself."
Mainstreaming Quantum Crypto? MagiQ/Cavium MagiQ Technologies has signed a deal with Cavium Networks to boost performance and lower costs through standardized engineering protocols, incorporating Cavium's network security chips into MagiQ's servers and creating designs for networking boards. Will quantum encryption go mainstream?
Coupling Flux Qubits You, Nakamura, and Nori "A central problem for implementing efficient quantum computing is how to realize fast operations, both one- and two-bit ones. However, this is difficult to achieve for a collection of qubits, especially for those separated far away, because the interbit coupling is usually much weaker than the intrabit coupling. Here we present an experimentally feasible method to effectively couple two flux qubits via a common inductance and treat both single and coupled flux qubits with more realistic models which include the loop inductance. The main advantage of our proposal is that a strong interbit coupling can be achieved using a small inductance, so that two-bit operations as fast as one-bit ones can be easily realized. We also show the flux dependence of the transitions between states for the coupled flux qubits." [ arXiv ]
Interpretation of Quantum Mechanics: Current Status and Future Directions Perimeter Institute Lecture Series A technical but pedagogical introduction to the problems associated with developing a consistent understanding of the nature of objective reality in light of quantum theory.