A strong loophole-free test of local realism

Published

December 16, 2015

Author(s)

Lynden K. Shalm, Evan Meyer-Scott, B. G. Christensen, Peter L. Bierhorst, Michael A. Wayne, Deny Hamel, Martin J. Stevens, Thomas Gerrits, Scott C. Glancy, Michael S. Allman, Kevin J. Coakley, Shellee D. Dyer, Adriana E. Lita, Varun B. Verma, Joshua C. Bienfang, Alan L. Migdall, Yanbao Zhang, William Farr, Francesco Marsili, Matthew D. Shaw, Jeffrey Stern, Carlos Abellan, Waldimar Amaya, Valerio Pruneri, Thomas Jennewein, Morgan Mitchell, P. G. Kwiat, Richard P. Mirin, Emanuel H. Knill, Sae Woo Nam

Abstract

We present a loophole-free violation of local realism using entangled photon pairs. We ensure that all relevant events in our Bell test are spacelike separated by placing the parties far enough apart and by using fast random number generators and high-speed polarization measurements. A high-quality polarizationentangled source of photons, combined with high- efficiency, low-noise, single-photon detectors, allows us to make measurements without requiring any fair-sampling assumptions. Using a hypothesis test, we compute p values as small as 5.9 x 10−9 for our Bell violation while maintaining the spacelike separation of our events. We estimate the degree to which a local realistic system could predict our measurement choices. Accounting for this predictability, our smallest adjusted p value is 2.3 x 10−7. We therefore reject the hypothesis that local realism governs our experiment.

Citation

Physical Review Letters

Volume

115

Pub Type

Journals

Download Paper

https://doi.org/10.1103/PhysRevLett.115.250402

Keywords

Bell inequality, local realism, entanglement

Citation

Shalm, L. , Meyer-Scott, E. , Christensen, B. , Bierhorst, P. , Wayne, M. , Hamel, D. , Stevens, M. , Gerrits, T. , Glancy, S. , Allman, M. , Coakley, K. , Dyer, S. , Lita, A. , Verma, V. , Bienfang, J. , Migdall, A. , Zhang, Y. , Farr, W. , Marsili, F. , Shaw, M. , Stern, J. , Abellan, C. , Amaya, W. , Pruneri, V. , Jennewein, T. , Mitchell, M. , Kwiat, P. , Mirin, R. , Knill, E. and Nam, S. (2015), A strong loophole-free test of local realism, Physical Review Letters, [online], https://doi.org/10.1103/PhysRevLett.115.250402 (Accessed October 13, 2025)