D-Wave broke the 1,000 qBit barrier

Friday, July 17 2015

The new chip at the core of D-Wave supports 1,000 quBits processing. Credit: D-Wave

D-Wave is for some the very first commercial quantum computer, for others it is just an imitation of the real thing supporting only a subset of the characteristics of a quantum computer.

It is produced by D-Wave Systems, in California, and it is being used by universities and by companies. Google among them, to address very specific tasks, like finding resemblance in images, a task that is easy for our brain and quite complex for a normal computer (that on the contrary is very good at point out differences, much better than our brain is).

Now they have announced a ned version of D-Wave able to process 1,000 quBits. This is doubling the quBits available in D-Wave 2, the current version.

In quantum computers doubling the number of quBits double the exponent of the potential parallel searches performed. So the current version supported 2exp512 searches, the new one supports 2exp1,000. And as you are well aware doubling the exponent is way more than doubling the number (10ext2 means 100, 10exp4 means 10,000)! In other words, this means that it can perform a number of parallel searchers that is greater than the number of atoms scientists think form the universe (10exp75).

The new processor consists of 128,000 Josephson tunnel junction and is embedded in a system that makes it run at a temperature that is 40% colder than the previous one. If you think that the previous temperature was close to the absolute zero, you understand what it means to get 40% colder.  Temperature is essential in keeping the quantum computer working maintaining the wave coherence which in practice allows a better identification of the results among the many possibile (a quantum computer assesses probability, it doesn't return a single "number", so in a way if you ask how much is 2+2 you get a slate of answers of different probability with 4 being the one most likely, but you have to single that out among thousands of others...).

You can also see, in a way, the various probabilities (waves) as different "sounds" and then you can understand that if these sounds gets mixed with unwanted "noise" picking up the right one gets even more difficult. Hence you can appreciate the importance that the new D-Wave has managed to decrease the overall noise by 50%.

Also notice that by working at near absolute 0 temperature the chip actually operates as a superconductor, and it is possible the most complex superconductor chip ever produced.

As many would say it is not a full blown quantum computer but is the best imitation we have so far!

Roberto Saracco