By Roy Illsley, senior research analyst, Butler Group

The European Space Agency (ESA) conducted an experiment to transmit photons over a distance of 144 Km in free space between Tenerife and La Palma in the Canary Islands, proving that Quantum Entanglement is a reality for free space communications over significant distances.

Quantum computing works differently to classic computing, where in classic computing binary digits can take on the value of a 1 or 0. In quantum computing its equivalent, a qubit, can be a 1, 0, or both at the same time. This superposition of states is possible because of the ambiguity inherent in quantum mechanics. Once a quantum computer has more than one qubit it is possible to exploit quantum entanglement.

Therefore, the importance of this seemingly academic experiment is enormous for the future of secure communications and quantum computing. Quantum entanglement is the basis for many other theories of quantum mechanics, such as quantum cryptography and quantum teleportation. Quantum entanglement was described by Albert Einstein as "spooky action at a distance". According to quantum mechanics, the quantum entanglement theory is that two entangled quantum states have to be described by reference to each other, even though the states may be physically separated.

The theory as proved by the ESA was to exploit entanglement over free space distances, by setting one qubit to register a value of 1 or 0, and according to theory it sets the other qubit to the same value despite the physical separation.

The possibilities of exploiting quantum mechanics to generate a secure communications link have been proposed by academics for many years. The ESA experiment demonstrates that quantum entanglement can be performed over significant distances.

However, to make the theory of practical use, it must be capable of satellite transmission which involves even greater distances. Heisenberg's uncertainty principle states that unlike classical Newtonian mechanics where the motion of a particle is described by a function of time and momentum in a deterministic or causal perspective, quantum mechanics takes a probabilistic or statistical perspective, which means that any measurement irreversibly disturbs any quantum state. Therefore, using this principle a message sent using a quantum communications link could not be eavesdropped, as the action of listening would destroy the message.

Butler Group considers the possibilities in quantum communications and quantum computation as representing a potential future; however, the biggest challenge is to translate the capabilities to commercial solutions that industry can exploit cost-effectively.

We believe that any commercial quantum-based products are at least 15 years away, but it is a technology that cannot be ignored. ENS