Development of a Quantum Repeater for Long-Distance Quantum Communication Using Photonic Information Storage

Abstract

Abstract : In this project, we have carried out the pioneering work for long-distance quantum communication using atomic ensembles for photon-state storage and for implementation of quantum repeaters. This work was followed by many groups and is now considered as one of the most promising approaches to overcoming photon losses in long-distance quantum communication. Specific highlights include theoretical proposals for quantum repeaters based on atomic ensembles (Nature, 414, 413, 2001), atom-atom correlations mediated by dark-state polaritons (Phys.Rev.Lett., 88, 243602, 2002), generation of stationary pulses of light (Phys.Rev.Lett, 89, 143602, 2002); experimental demonstrations of atomic memory for correlated photon states (Science, 301, 196, 2003), stationary pulses of light (Nature 426, 638, 2003), shaping quantum pulses via atomic memory (Phys.Rev.Lett. 93, 233602, 2004)), and finally realization of two-node quantum network involving generation and storage of single photon pulses in two remote ensembles (Nature, 438, 837, 2005). Finally, we proposed and analyzed a novel method that uses fixed, minimal physical resources to achieve generation and nested purification of quantum entanglement for quantum communication over arbitrarily long distances. In this method, solid-state single photon emitters with two internal degrees of freedom formed by an electron spin and a nuclear spin are used to build intermediate nodes in a quantum channel (Phys.Rev.Lett. 96,070504, 2006). Recently, we have experimentally demonstrated such a node using Nitrogen-Vacancy centers in room temperature diamond lattice (submitted to Science, 2007).