Correlations, indistinguishability and entanglement in Hong-Ou-Mandel experiments at microwave frequencies Journal Article


Author(s): Lang, C; Eichler, Christopher; Steffen, L. Kraig; Fink, Johannes; Woolley, Matthew J; Blais, Alexandre; Wallraff, Andreas
Article Title: Correlations, indistinguishability and entanglement in Hong-Ou-Mandel experiments at microwave frequencies
Affiliation
Abstract: When two indistinguishable single photons impinge at the two inputs of a beam splitter they coalesce into a pair of photons appearing in either one of its two outputs. This effect is due to the bosonic nature of photons and was first experimentally observed by Hong, Ou and Mandel. Here, we present the observation of the Hong-Ou-Mandel effect with two independent single-photon sources in the microwave frequency domain. We probe the indistinguishability of single photons, created with a controllable delay, in time-resolved second-order cross- and auto-correlation function measurements. Using quadrature amplitude detection we are able to resolve different photon numbers and detect coherence in and between the output arms. This scheme allows us to fully characterize the two-mode entanglement of the spatially separated beam-splitter output modes. Our experiments constitute a first step towards using two-photon interference at microwave frequencies for quantum communication and information processing.
Journal Title: Nature Physics
Volume: 9
Issue 6
ISSN: 1745-2473
Publisher: Nature Publishing Group  
Date Published: 2013-06-01
Start Page: 345
End Page: 348
Sponsor: This work was supported by the European Research Council (ERC) through a Starting Grant and by ETHZ. L.S. was supported by EU IP SOLID. A.B. and M.J.W. were supported by NSERC, CIFAR and the Alfred P. Sloan Foundation
DOI: 10.1038/nphys2612
Open access: no