Quantum mechanics

Chromatography

Cascade

Radiative transfer

Local hidden variable theory

Statistical physics

Physical chemistry

Polarization (electrochemistry)

Photon

Physics

Quantum entanglement

Quantum

Chemistry

Birefringence

Bell's theorem

Polarizer

Physical Review Letters

We have measured the linear polarization correlation of the photons emitted in a radiative atomic cascade of calcium. A high-efficiency source provided an improved statistical accuracy and an ability to perform new tests. Our results, in excellent agreement with the quantum mechanical predictions, strongly violate the generalized Bell's inequalities, and rule out the whole class of realistic local theories. No significant change in results was observed with source-polarizer separations of up to 6.5 m.

Experimental Tests of Realistic Local Theories via Bell's Theorem