An experimental test of noncontextuality without unphysical idealizations.
To make precise the sense in which nature fails to respect classical physics, one requires a formal notion of classicality. Ideally, such a notion should be defined operationally, so that it can be subject to direct experimental test, and it should be applicable in a wide variety of experimental scenarios so that it can cover the breadth of phenomena thought to defy classical understanding. Bell's notion of local causality fulfils the first criterion but not the second. The notion of noncontextuality fulfils the second criterion, but it is a long-standing question whether it can be made to fulfil the first. Previous attempts to test noncontextuality have all assumed idealizations that real experiments cannot achieve, namely noiseless measurements and exact operational equivalences. Here we show how to devise tests that are free of these idealizations. We perform a photonic implementation of one such test, ruling out noncontextual models with high confidence.
Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario Canada N2L 3G1.|Department of Physics &Astronomy, University of Waterloo, Waterloo, Ontario Canada N2L 3G1.
Michael D
MD
Mazurek
Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, Ontario Canada N2L 2Y5.
Matthew F
0000-0002-6189-7144
MF
Pusey
Optics &Quantum Information Group, The Institute of Mathematical Sciences, C.I.T Campus, Taramani, Chennai 600 113, India.
Ravi
0000-0002-3978-5971
R
Kunjwal
Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario Canada N2L 3G1.|Department of Physics &Astronomy, University of Waterloo, Waterloo, Ontario Canada N2L 3G1.
Kevin J
KJ
Resch
Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, Ontario Canada N2L 2Y5.
Robert W
RW
Spekkens