Definition of quantum computing

Quantum computing  promises to transform information technology over the next few decades, as electronic computing reaches the limits of what is physically possible with conventional chips and circuitry.

The empirical observation called Moore's Law predicts that more and more transistors can be packed in microprocessors over time, meaning that computing power can continue to increase while chips continue to shrink in size. This implies that computers can perform a series of operations in exponentially shorter periods of time.

However, this miniaturisation of electronics is limited by the laws of physics. If Moore's Law were to hold, in a few years, one would need to have transistors the size of an atom, which is naturally impossible. This limit in computational power can be overcome if computers could perform multiple computations simultaneously. 

The theory behind the quantum computer is to use atoms, instead of silicon chips, to process data at a faster speed than today's computers.

Quantum computing is based on the concept in physics that sub-atomic particles can be in more than one place at once. In quantum computing the digital binary code of either 1 or zero, representing on and off, is replaced by quantum computing qubits which not only allow the state of neither one nor zero to exist but also permit the idea that a value could be both 1 and zero and all points between simultaneously. The idea is that, freed of its "either-or" constraint that a quantum computer could be much faster than a super computer. Quantum computing is still in its early stages of development and is still trying to overcome the problem that if you look at subatomic particles you could bump into them and thereby change their value.

 

Quantum computing in the news

In February 2014 a writer in the FT attempted to provide a round up of where the world had got to with quantum computing. The writer poinnted out that although Google and Nasa had jointly invested $10m on a prototype quantum computer from D-Wave Systems, that there remained a simmering debate on whether the computers were quantum at all, despite observable quantum effects.