Everyone likes new gadgets. What to buy for a multibillion dollar corporation that has everything? Google has bought a new quantum computer – a giant leap in computing that was only a physicist’s fantasy a decade ago. Over this piece we will look at what quantum computing is, and the possibilities for the technology into the future.

What is a quantum computer?

Quantum computers can think in a much more complicated way than binary computers used today. It is as if, from two dimensional thinking, a quantum computer can think in “3-D”.

The machines you and I use work in binary code. A simple explanation of binary code can be found here. In its calculations every second all the activities we do on our PC are either 0 or 1 (and combinations thereof). We know about transistors on chips – they have capacitors on them, on which the binary code is registered as either “on” for 1 or “off” for 0. Each capacitor is known as a “bit”.

In quantum physics it has been shown that atoms can have two states of energy. Put simply, they can be at a high energy state and at a low energy state simultaneously. If they were capacitors on a transistor they could be on and off at the same time. Each atom on such a machine is known as a “qubit” or quantum bit.

According to the qubit foundation based in Oxford, England, “If we keep adding qubits to the register we increase its storage capacity exponentially i.e. three qubits can store 8 different numbers at once, four qubits can store 16 different numbers at once”.

The first time a computer was used in anger by a government was at Bletchley Park to crack the Nazi Enigma code in the 1940’s. In the 1980’s someone worked out that quantum computing would be even better at code breaking. From theoretical physics, so people got seriously interested in developing such computers.

According to the qubit foundation, factorization is a serious problem for computers. “Consider, for example, the following factorisation problem

? x ? = 29083.

How long would it take you, using paper and pencil, to find the two whole numbers which should be written into the two boxes (the solution is unique)? Probably about one hour. Solving the reverse problem

127 x 129 = ?,

again using paper and pencil technique, takes less than a minute. All because we know fast algorithms for multiplication but we do not know equally fast ones for factorisation.”

On current computers, the qubit foundation suggest, “No one can even conceive of how one might factorise, say, thousand-digit numbers; the computation would take much more that the estimated age of the universe.” A computer that can consider thousands of solutions at the same time would knock down the calculation times considerably.

Google’s gadget

NASA and Google have shared ownership on a 512 qubit machine. That is blisteringly fast! Tests by the company that developed it, D-Wave, suggest that, calculation for calculation, their quantum computers are on average 3600 times faster than the supercomputers on the market today. Put in perspective, the UK Met Office uses one of the fastest computers in the world, which does 1000 billion (9 zeroes) calculations a second. An equivalent quantum machine would work at 3000 trillion (12 zeroes) calculations per second!

A big, black box with "DWave" written on it

Google isn’t revealing what it is using the computer for though much of the research, according to D-Wave “is to use quantum computing to advance machine learning in order to solve some of the most challenging computer science problems.” These include “machine learning, web search, speech recognition, planning and scheduling, search for exoplanets, and support operations in mission control centers.”

The future of quantum computing?

Using atoms as capacitors on chips has been the dream of hardware developers for many years. Quantum computing is doing precisely this. As technology progresses, the dreams and fantasies of science fiction writers over the years will be realised. A smart phone that is several thousand times faster than one on the market today? Never mind your embedded satnav system in your car – how about a smartphone that can drive your car for you?