Random numbers might sound like they are useless. After all, a calculator that spits out random numbers would not be helpful. But in fact, randomness is very valuable. Why is this? Because it cannot be predicted ahead of time and that is extremely useful. The first random numbers were generated for lotteries, where millions of pounds needed to be allocated fairly. Then, they were used for encryption, to scramble messages sent by the government or the military. Nowadays they are used to simulate noise in computations that rely on statistical fluctuations, and they underpin a large and lucrative gaming industry.

However, before quantum physics, randomness was just an approximation: if you really knew exactly how a coin was flipped, or a roulette ball was thrown, you could in principle predict the outcome. But this is no longer possible with single atoms or single particles of light. These systems obey quantum mechanics, where as far as anyone knows, it seems that randomness is a fundamental property. The results of certain measurements simply cannot be predicted, even if you had perfect knowledge of the entire universe and its history.

A proof-of-principle experiment is currently underway and we are in discussions with industrial partners to produce a prototype device.