Controlling quantum entanglement with classical non-separable light

TL;DR

This paper demonstrates how classical non-separable light fields can control quantum entanglement during frequency conversion, revealing a duality between classical coherence and quantum channels, with experimental validation.

Contribution

It establishes a theoretical and experimental link between classical non-separability and quantum entanglement dynamics in frequency conversion processes.

Findings

Quantum channel is dual to classical coherence matrix.

Entanglement evolution is limited by classical non-separability.

Frequency conversion acts as a swap between classical non-separability and entanglement.

Abstract

Here we investigate the quantum frequency conversion of entangled photons driven by a classically non-separable laser beam. We show that the frequency conversion dynamics is described by a quantum channel that stems from the classical drive field through the channel-state duality - the quantum channel is dual to the classical coherence matrix of the drive field. This implies that the evolution of entanglement in the conversion process is bound by the classical non-separability of the drive field, a result that we confirm experimentally. Furthermore, we show that the conversion dynamics can be understood as a swapping operation between classical non-separability and entanglement, unveiling a physical connection between two fundamentally different concepts.