New qubit control bodes well for future of quantum computing

Yale University scientists have found a way to observe quantum information while preserving its integrity, an achievement that offers researchers greater control in the volatile realm of quantum mechanics and greatly improves the prospects of quantum computing.

Quantum computers would be exponentially faster than the most powerful computers of today.

''Our experiment is a dress rehearsal for a type of process essential for quantum computing,'' said Michel Devoret, the Frederick William Beinecke Professor of Applied Physics & Physics at Yale and principal investigator of research published on 11 January in the journal Science.

''What this experiment really allows is an active understanding of quantum mechanics. It's one thing to stare at a theoretical formula and it's another thing to be able to control a real quantum object.''

In quantum systems, microscopic units called qubits represent information. Qubits can assume either of two states - ''0'' or ''1'' - or both simultaneously. Correctly recognising, interpreting, and tracking their state is necessary for quantum computing. However, the act of monitoring them usually damages their information content.

The Yale physicists successfully devised a new, non-destructive measurement system for observing, tracking and documenting all changes in a qubit's state, thus preserving the qubit's informational value. In principle, the scientists said, this should allow them to monitor the qubit's state in order to correct for random errors.