Are we heading for a quantum leap in communications?

A fundamental principal of this research is a long distance telecommunication link which is impossible for hackers to breach. It is believed that the technique could also underpin the creation of a new form of ‘quantum internet’.

Scientists have previously used the phenomenon of quantum entanglement to allow the exchange of information over short distances. Entanglement allows particles which are physically separated to nonetheless share properties.

This process of entanglement also allows scientists to encode information in quantum particles, similar to the way in which the ones and zeroes (known as bits) of digital communication are used to encode data. Two computers sharing quantum information are much more secure, as any interception by a third party will change the properties of the data itself, allowing easy detection by the intended recipient.

To allow quantum computers to communicate with each other, a new type of quantum internet capable of transmitting the special quantum bits (known as qubits) over long distances will need to be built.

The team, co-ordinated by University of Glasgow postdoctoral research fellow Dr Chandra Mouli Natarajan, together with colleagues at Stanford, managed to create long distance telecommunication link for a stationary quantum bit for the first time. They created correlations between a spin of an electron stored in a tiny crystal of semiconducting material known as a ‘quantum dot’ and the arrival time of single photon across two kilometres of fibre-optic cable used in standard telecoms.

Natarajan commented: “The physics behind quantum communication, by their very nature, make data transfer utterly secure - any tampering with either side of the communication will be immediately apparent because it will affect the quantum correlations. Our work is an important step towards creating architectures for the future hybrid quantum internet.”