### Published in Physics World, 11 Apr 2014

A quantum-information analogue of the transistor has been unveiled by two independent groups in Germany and the US. Both devices comprise a single atom that can switch the quantum state of a single photon. The results are a major step towards the development of practical quantum computers.

Unlike conventional computers, which store bits of information in definite values of 0 or 1, quantum computers store information in qubits, which are a superposition of both values. When qubits are entangled, any change in one immediately affects changes in the others. Qubits can therefore work in unison to solve certain complex problems much faster than their classical counterparts. […]

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