Experimental quantum multiparty communication protocols
Massimiliano Smania, Ashraf M Elhassan, Armin Tavakoli, Mohamed Bourennane · npj Quantum Information · 2016
Quantum information science breaks limitations of conventional information transfer, cryptography and computation by using quantum superpositions or entanglement as resources for information processing. Here we report on the experimental realisation of three-party quantum communication protocols using single three-level quantum system (qutrit) communication: secret-sharing, detectable Byzantine agreement and communication complexity reduction for a three-valued function. We have implemented these three schemes using the same optical fibre interferometric setup. Our realisation is easily scalable without compromising on detection efficiency or generating extremely complex many-particle entangled states. Quantum-mechanically secure communication between three different parties has been achieved by researchers in Sweden. Mohamed Bourennane and colleagues at Stockholm University achieved this by sharing a three-state quantum object across an optical fiber network. Quantum cryptography takes advantage of the unusual properties of quantum particles to achieve a degree of security beyond that possible in any classical communication system. Often this relies on linking two particles through a quantum mechanical connection known as entanglement; however, entanglement can be difficult to create. The scheme used by Bourennane's team uses just a single quantum object known as a qutrit that can exist in one of three states. The team demonstrated three different protocols known as secret sharing, detectable Byzantine agreement and communication complexity reduction. The method shows potential for scaling up to large-scale applications.