Einstein-Podolsky-Rosen Paradox with Position-Momentum Entangled Macroscopic Twin Beams

TL;DR

This paper demonstrates the Einstein-Podolsky-Rosen paradox using bright, macroscopic twin beams of light, revealing spatial entanglement and hyperentanglement through quantum correlations in position, momentum, and time.

Contribution

It provides the first demonstration of the EPR paradox with bright twin beams in position-momentum form, showing quantum correlations at a macroscopic photon level.

Findings

Violation of the uncertainty principle by over an order of magnitude.

Observation of spatial squeezing in bright twin beams.

Evidence of hyperentanglement in spatial and temporal degrees of freedom.

Abstract

Spatial entanglement is at the heart of quantum enhanced imaging applications and high-dimensional quantum information protocols. In particular, for imaging and sensing applications, quantum states with a macroscopic number of photons are needed to provide a real advantage over the classical state-of-the-art. We demonstrate the Einstein-Podolsky-Rosen (EPR) paradox in its original position and momentum form with bright twin beams of light by showing the presence of EPR spatial (position-momentum) entanglement. An electron-multiplying charge-coupled-device camera is used to record images of the bright twin beams in the near and far field regimes to achieve an apparent violation of the uncertainty principle by more than an order of magnitude. We further show that the presence of quantum correlations in the spatial and temporal degrees of freedom leads to spatial squeezing between the spatial fluctuations of the bright twin beams in both the near and far fields. This provides another verification of the spatial entanglement and points to the presence of hyperentanglement in the bright twin beams.