PURE randomness is surprisingly difficult to create, even if you draw on the inherent randomness of quantum mechanics. Now, though, a “true” random number generator is on the cards, which may help create the ultimate cryptographic messages.
Existing quantum random number generators are only as reliable as their parts. For example, some devices send single photons through a and record the path taken, but a pattern could emerge over time if the beam-splitter comes to favour one direction or the materials degrade. A new number generator produces random strings of numbers without the worry of such flaws, because it relies on the inherently random behaviour of two quantum-entangled objects.
“The new number generator relies on the inherently random behaviour of two entangled objects”
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Entangled objects violate the ““, which provides mathematical proof that their behaviour is definitively random. It doesn’t matter who made the objects or how, says team member of the Institute for Photonic Sciences in Barcelona, Spain.
Two ytterbium ion quantum bits or qubits were trapped in separate vacuum chambers. When they each emitted a photon, the interactions between the photons entangled the two ions. The team fed numbers into the device, causing microwave oscillators to turn the qubits in one of two directions. The qubits were then exposed to light, and a random string of ones and zeros was recorded, depending on whether or not they shot photons to a detector. We know that the ions are entangled because they emit photons in the same way.
To remove any chance of human error during measurement, this string was fed into a mathematical formula that removed traces of pattern, but cannot generate randomness itself (Nature, ).
“If the same task can be implemented over some distance, it can lead to device-independent cryptography,” says cryptography pioneer of the University of Oxford.
