Picture this: a single electron in a vacuum, totally isolated and unobserved. It seems like this would be useless and a huge waste of money to set up – a symptom of mad science becoming irrelevant to most people’s lives.
Yet that electron is possibly the greatest discovery mankind has ever made. It can help us find a cure for cancer or find new prime numbers millions of digits long. The benefits of the so-called quantum computing that uses particles like electrons to compute faster than ever before are tangible and profound: they affect people’s lives every day.
Why is that electron important? It can perform calculations.
Any system which can be observed by a human to be in two or more states – let’s call them ‘on’ and ‘off’ – can be used in an arrangement to perform calculations: to do sums. These sums are the basis on which all society is based, because it’s how computers work, how they display information.
An endless, meaningless string of 1s and 0s under the hood are commonly known to be how computers function, but what do they actually mean? Each binary digit (a 1 or a 0) is the output of a tiny electrical gate called a transistor. A small electrical current either flows through the gate or it gets stopped, and an ‘on’ or ‘off’ signal is carried through to the next gate.
Millions of these little gates form vast networks of transistors on a circuit board (green plastic plates that control every piece of electrical equipment you own), and we’ve got to the point where we can make them so small that the electrical current – however tiny it is – can jump across from one gate to the other, causing errors in calculations.
The odd jumps that the electricity can make are hardly surprising: the transistors are so small that you can fit billions on a 5p-sized chip (tiny wafers of silicon that house transistors). Companies like Intel are getting slower and slower at producing smaller chips, as the challenges with physics get tougher at the minute scale they work at.
You don’t need microscopic silicon transistors to do sums, though. Remember: we can do calculations using any series of objects that you can put in those ‘on’ or ‘off’ states. Like a domino line, for example. Using just a few fallen or upright dominoes you can do all manner of simple – and even some complex – maths problems.
That’s where we get to the electron from earlier. We are just beginning to pioneer an entirely new method of computing – and it doesn’t even use physical matter any more. Moving beyond the (albeit tiny, but still physical) silicon transistors that have been used from decades is a radical step, and one that requires software coders and physicists making the new computers totally rethink the way they work.
It’s called quantum computing, and it uses single particles (or in some cases, pseudo-particles that don’t even really exist) like an electron, measuring their ‘on’ or ‘off’ states and using them to perform calculations. They are so fast at doing this because the electron, whilst unobserved, can be in both the on and off states at one time due to quantum theory (see Schrodinger’s cat). Whilst a silicon gate can only think in terms of 1 or 0, a qbit (quantum gate) can think in multiple ways at the same time.
Technology is moving fast away from the realm of the physical that we mortals live and love in. But that’s no reason to stop the research. The benefits of faster quantum computers are massive in finding cures for diseases or simulating space travel. This science is relevant to everyone.
--Will Allsopp is a student at King Edward VI School, Bury St Edmunds