18 May 2010 Quantum Random Networks

Quantum random network (Artist’s conception)

Nature Physics publishes a joint paper on the concept by researchers at ICFO and Max-Planck-Institute for Quantum Optics. The paper \"Quantum Random Networks\" merges the fields of complex random networks and quantum networks. It has been published in Nature Physics by Dr. Sébastien Perseguers, Max-Planck-Institute for Quantum Optics at Garching, Germany; ICFO/ICREA Professors Maciej Lewenstein and Antonio Acin; and Prof. Ignacio Cirac, Max-Planck-Institute for Quantum Optics and Distinguished Invited Professor at ICFO.

Complex random networks constitute one of the most rapidly developing interdisciplinary areas of Science because of their flexibility and broad range of applications. On the other hand, the study of quantum networks, in which distant quantum nodes are connected by quantum states, represents an extremely relevant scenario in quantum information theory. The study of these networks is crucial for the development of quantum communication and cryptography or to the networking of the future quantum computers.

In the present Nature Physics article, the authors merge these two fields and introduce the concept of Quantum Random Graphs. By studying complex networks based on the laws of quantum physics, they reveal completely new features of these systems. Remarkably, novel effects with no classical analogue become possible thanks to the quantum features. In particular, the authors show that all the critical entanglement exponents z for the appearance of subgraphs in a random network collapse onto exactly one point. This is in strong contrast with the analogue result for classical networks, where different subgraphs appear for different values of z.