Monday, December 05, 2005

"QUANTUM: NIST claims largest quantum computer"

Scientists at the National Institute of Standards and Technology predict a sixfold improvement in the speed of synchronizing atomic clocks, and more than a doubling of magnetic-sensor sensitivity, by applying the lessons learned from NIST's demonstration of the world's largest quantum computer. NIST showed that six qubits could be entangled in synchronized "Schrödinger's cat" states of superposition — simultaneously spinning "up" and "down" — thereby enabling both ones and zeros to be superimposed. The previous world's record was an IBM Corp. five-qubit-device quantum computer using flourine atoms ( instead of the beryllium atoms used here by NIST. In applications, Schrödinger cat states could make it possible to set atomic clocks six times faster than today, since it would be six times easier to synchronize their frequencies. Likewise, entangled qubits could enable fault tolerance in quantum computers by providing sixfold easier verification that a quantum calculation had been performed without disturbances. NIST also proposes using the six-synchronized states to build more-sensitive sensors. Higher sensitivity to disturbances could enable quantum encryption algorithms that would foil undetected eavesdropping. The NIST experiment held the six atoms stationary in an electromagnetic trap. It used ultraviolet lasers to cool them almost to absolute zero and then synchronize their states by entangling them. The Schrödinger cat states lasted about 50 microseconds and could be repeated every millisecond.