Entangled Quantum Networks ICFO|ICREA|Max-Planck I...

Entangled Quantum Networks ICFO|ICREA|Max-Planck Institute In Nature Physics advance publication 10.1038/nphys549, Acin et al. draw upon the classical percolation methods of statistical mechanics to optimize entanglement distribution through quantum networks. " We argue that there exists an entanglement phase transition in quantum networks which may be exploited to obtain very efficient protocols. This work opens a new set of problems in quantum information theory, which are related to statistical physics, but pose completely new challenges in these fields [...] The work leads to a novel type of critical phenomenon, an entanglement phase transition that we call entanglement percolation. "

Maximizing entanglement in quantum networks. Each node is connected by a state consisting of two copies of the same two-qubit state. The nodes marked in (a) make the optimal measurement for the one-repeater configuration on pairs of qubits belonging to different connections. (b) A triangular lattice is obtained where the maximally entangled state for each connection is the same as for the two-qubit state. Acin et al., Nature Physics, 25 February 2007.