Demonstration of Einstein-Podolsky-Rosen Steering Using Single-Photon Path Entanglement and Displacement-Based Detection

T. Guerreiro, F. Monteiro, A. Martin, J. B. Brask, T. Vértesi, B. Korzh, M. Caloz, F. Bussières, V. B. Verma, A. E. Lita, R. P. Mirin, S. W. Nam, F. Marsilli, M. D. Shaw, N. Gisin, N. Brunner, H. Zbinden, and R. T. Thew

Phys. Rev. Lett. 117, 070404 – Published 12 August 2016

Our paper demonstrating the violation of an Einstein-Podolsky-Rosen steering inequality developed for single-photon path entanglement with displacement-based detection has been published in Physical Review Letters. We use a high-rate source of heralded single-photon path-entangled states, combined with high-efficiency superconducting-based detectors, in a scheme that is free of any post-selection and thus immune to the detection loophole. This result conclusively demonstrates single-photon entanglement in a one-sided device-independent scenario, and opens the way towards implementations of device-independent quantum technologies within the paradigm of path entanglement. An open access (arXiv) version can be found here.

Experimental setup. A heralding single-photon source is coupled into fiber and incident on a fiber BS, generating heralded entanglement, while local oscillator states, switched by an EOM, are coupled into the same BS with orthogonal polarization. Weak displacements, D(alpha), D(beta), are performed in an all-fiber configuration (inset) followed by single-photon detectors that constitute the displacement-based detection.

This was a collaboration between several groups, Nicolas Brunner and Jonatan Brask here in Geneva as well as Tamas Vertesi in Debrecen, Hungary on the theory side, and experimentally, Sae Woo Nam's group in NIST and Francesco MArsilli's group at JPL, whom we work with for the development of superconducting single photon detectors.