## Tech Explained: Quantum Computing

Tech Explained

### Our new Tech Explained brings you up to speed with the future of computing by identifying what makes quantum computing so different and how it can be used to manipulate subatomic particles.

The processing power required by consumers and businesses is rapidly growing. Eventually computers will need to develop new ways of storing data in order to keep up. In 1965, Gordon Moore proposed Moore’s Law, which stated the number of transistors on a microprocessor would double every 2 years (this was later changed to 18 months). At this rate, by the year 2030 the circuits on a microprocessor will need to be measured on an atomic scale. The next logical step is quantum computers, in which computers use atoms and molecules to store data. Such quantum computers have the potential to perform certain calculations significantly faster than any silicon-chip-based computer. So, what is a quantum computer and will they be available any time soon?

Most digital computers are based on an idea first developed by Alan Turing in the 1930s. Turing devised a way to divide information into a string of 1s and blank spaces (0s). A device reads the pattern of symbols and blanks, and this pattern makes up the instructions to the machine. Modern computers still use a similar system of ‘bits’ which can exist in one of two states – 0 or 1. Quantum computers, however, take advantage of the fact that subatomic particles like electrons, photons and ions can exist in more than one state at any time. Thus, a quantum bit, or ‘qubit’, which is made up of these particles can be a 0, a 1 or both 0 and 1 (and all points in between) at the same time. While a computer based on the Turing principle can only perform one calculation at a time, a quantum computer can, in theory, perform many calculations at once. Not only can quantum computers use and store far more information than Turing computers, but they can do it using less energy.

Although quantum computers could perform normal computing tasks, they could also be used for specialised functions that today’s standard computers cannot manage. Because quantum computers could operate so quickly, they would be especially well suited to solving very complex mathematical calculations. This may seem like an esoteric use of so much computing power, until you realise that most of the systems that keep our online information secure are based on mathematical problems that are very difficult to solve. So, quantum computers could potentially allow greater security, but at the same time make hacking secure systems much easier.

Quantum computers could also be used to rapidly model complicated chemical reactions. In fact, Google engineers have already used a simple quantum device to simulate a hydrogen molecule, and IBM has used similar computers to model the behaviour of more complex molecules. Quantum computers could eventually allow researchers to quickly design new molecules for use in medicine, or all new chemical processes.

So far, companies like Google and IBM have been racing to achieve ‘quantum supremacy’. This is the point at which quantum computers overtake the processing ability of conventional computers. Although IBM managed to construct a working 50-qubit quantum computer in 2017, the system could only hold its quantum microstate for 90 microseconds. This was a record, but it is still a far cry from creating a system that is ready for practical use. In February 2018, Intel announced that it had found a way of fabricating quantum chips from silicon, a step which could bring practical quantum computers closer.

A handful of start-ups are also working to crack practical quantum computing. At Springwise, we have highlighted examples of quantum algorithms, electron refrigerators to keep quantum computers cool and designs for the large-scale manufacture of quantum chips.

30th October 2018