Realization of the purely spatial Einstein-Podolsky-Rosen paradox in full-field images of spontaneous parametric down conversion

TL;DR

This paper demonstrates a rigorous spatial EPR paradox using full-field imaging of spontaneous parametric down-conversion, showing quantum correlations without postselection in both near and far fields.

Contribution

It presents the first full-field, postselection-free demonstration of the spatial EPR paradox in the position-momentum form.

Findings

Violation of Heisenberg inequalities with all biphoton pairs included

Quantum correlations observed in both near and far fields

No postselection required for demonstrating EPR paradox

Abstract

We demonstrate Einstein-Podolsky-Rosen (EPR) entanglement by detecting purely spatial quantum correlations in the near and far fields of spontaneous parametric down-conversion generated in a type-2 beta barium borate crystal. Full-field imaging is performed in the photon-counting regime with an electron-multiplying CCD camera. The data are used without any postselection, and we obtain a violation of Heisenberg inequalities with inferred quantities taking into account all the biphoton pairs in both the near and far fields by integration on the entire two-dimensional transverse planes. This ensures a rigorous demonstration of the EPR paradox in its original position momentum form.