Testing for entanglement with periodic coarse-graining

TL;DR

This paper introduces a novel method for detecting entanglement in continuous variable quantum systems using periodic coarse-grained measurements, enabling efficient analysis without full probability density reconstruction.

Contribution

The authors experimentally demonstrate new entanglement criteria based on periodic measurements, improving detection efficiency in continuous variable systems.

Findings

Achieved ~60% success rate in entanglement detection

Utilized spatial masks as mode analyzers over the entire transverse field

Avoided the need for probability density reconstruction

Abstract

Continuous variables systems find valuable applications in quantum information processing. To deal with an infinite-dimensional Hilbert space, one in general has to handle large numbers of discretized measurements in tasks such as entanglement detection. Here we employ the continuous transverse spatial variables of photon pairs to experimentally demonstrate novel entanglement criteria based on a periodic structure of coarse-grained measurements. The periodization of the measurements allows for an efficient evaluation of entanglement using spatial masks acting as mode analyzers over the entire transverse field distribution of the photons and without the need to reconstruct the probability densities of the conjugate continuous variables. Our experimental results demonstrate the utility of the derived criteria with a success rate in entanglement detection of $\sim60\%$ relative to $7344$ studied cases.