A new way to change quantum spin states on ultrafast time scales (femtoseconds) by manipulating electron spins could pave the way for all-optical quantum computation in solids by loosening the stringent requirements on coherence times.

Researchers at the University of California at Santa Barbara used 10^-13 second pulses of laser light to “tip” the spin alignment of the electrons.

The results were published in the June 29 issue of Science.

“Conventional computer bits consist of miniature electronic switches that are either off or on (0 or 1),” UCSB physicist David Awschalom said. Quantum-bits can be any combination thereof, for example 41% on, 59% off.” This property, he says, “enables computational algorithms with exponentially improved speed and fundamentally different functionality.”