Squeezed quantum communication: Flashes of light in quantum states transmitted through atmosphere

It could be difficult for the NSA to hack encrypted messages in the future -- at least if a technology being investigated by scientists at the Max Planck Institute for the Science of Light in Erlangen and the University Erlangen-Nürnberg is successful: quantum cryptography. The physicists are now laying the foundation to make this technique, which can already be used for the generation of secret keys, available for a wider range of applications. They are the first scientists to send a pulse of bright light in a particularly sensitive quantum state through 1.6 kilometres of air from the Max Planck Institute to a University building. This quantum state, which they call squeezed, was maintained, which is something many physicists thought to be impossible.