Original URL: http://www.theregister.co.uk/2012/02/28/quantum_computing_ibm_research/

Quantum computing IN OUR LIFETIME - IBM breakthrough

Big Blue boffins crack pesky unstable qubit puzzle

By Brid-Aine Parnell

Posted in Science, 28th February 2012 14:02 GMT

IBM boffins reckon their research has catapulted quantum computing forward a few decades, making it possible within our lifetime.

The scientists say that they've come up with a way to extend the amount of time that qubits retain their quantum state, thereby reducing errors in computations.

“In the past, people have said, maybe it’s 50 years away, it’s a dream, maybe it’ll happen sometime,” Mark Ketchen, manager of the physics of information group at IBM’s Watson Research Centre, told the New York Times. “I used to think it was 50. Now I’m thinking like it’s 15 or a little more. It’s within reach. It’s within our lifetime. It’s going to happen.”

In quantum computing, conventional binary bits are replaced by qubits, which can be 1, 0 or both. However, until now, qubits have been unstable: the pesky things tend to lose their quantum mechanical properties and go incoherent in a fraction of a second.

Big Blue has been experimenting with "three dimensional" superconducting qubits, first examined at Yale University, and has found a way to extend the quantum coherence of the qubits by up to 100 microseconds, two to four times greater than previous records.

It doesn't sound like much time, but the value just slides past the minimum threshold to allow effective error correction in the computations.

“The superconducting qubit research led by the IBM team has been progressing in a very focused way on the road to a reliable, scalable quantum computer," David DiVincenzo, professor at the Institute of Quantum Information at Aachen University and Forschungszentrum Juelich, said in a canned statement from IBM.

"The device performance that they have now reported brings them nearly to the tipping point; we can now see the building blocks that will be used to prove that error correction can be effective, and that reliable logical qubits can be realised."

The breakthrough means that scientists can now start looking at some of the other (many) problems with quantum computing, like how to scale up from individual qubits, how anyone could ever afford to build a quantum computer, how you would program it and how to get the answers out of it once it's done with its madly complicated computations.

IBM was presenting the results at a meeting of the American Physical Society in Boston today. ®