Adiabatic quantum computers may get speed boost using useless qubits

By Chris Lee | Published about 2 hours ago

Way back in... 2007, I co-authored an Ars report on a commercial quantum computer. In a series of articles, we revealed ourselves to be very skeptical of the D-Wave product and motivations. In the intervening years, I have had a change of heart. What has changed my mind? Simply put, the scientists at D-wave have been producing a series of solid and interesting papers. Each of these papers has answered specific criticisms of the original idea.

So, when D-Wave System's Neil Dickson sent me a copy of a paper he had placed in the arXiv that purported to solve the energy crossing problem, I was excited. I was also busy, so I'm a bit late reporting on this.

Adiabatic quantum computing—D-Wave now refers to this as adiabatic quantum optimization, which is more accurate, but I am retaining the old term to keep the link between various articles clear—uses a sort of annealing approach to solving computing problems. The basic idea is that many problems can be expressed as an energy landscape, and the solution to the problem is the lowest point in that landscape.

So far, so good. But on the face of it, this simply exchanges one problem for another: how do we figure out the lowest energy state of our system. It turns out that this problem is as difficult as the original problem, so we have to employ a trick.

more

http://arstechnica.com/science/news/2011/06/adiabatic-quantum-computers-may-get-speed-boost-by-adding-useless-qubits.ars

....rapid composition of chain-emails and extraction of recipes based on "tomato paste".