Recent revelations of online snooping on an epic scale, by government agencies which may well have been breaking the law, have prompted some users of the internet to ask who you can trust with sensitive data these days. According to Artur Ekert, an Oxford academic who moonlights as director of the Centre for Quantum Technologies (CQT) in Singapore, one possibility is a defunct Irish physicist called John Stewart Bell.
In 1964 Bell proposed a test to settle once and for all whether quantum mechanics really is as weird as it famously appears to be, in that it allows for instantaneous communication between two particles, no matter how far apart they are, on condition that they were once entangled together in the same place. The short answer, as experiments carried out over subsequent decades have shown, is yes, it is. Bell’s test, however, also led physicists like Dr Ekert to a remarkable insight: made sufficiently sensitive the Bell test could be used to guarantee perfectly secure communication—even if the equipment used to send and receive those communications had been sold to you by a manufacturer subverted by your enemies.
To read more, click here.