From Wavefunctional Entanglement to Entangled Wavefunctional Degrees of Freedom

TL;DR

This paper explores the relationship between photon entanglement and wavefunctional degrees of freedom, providing a new theoretical perspective that clarifies their connection and implications for quantum information processing.

Contribution

It offers a novel theoretical insight into how entangling interactions between optical modes can be distilled into genuine entanglement of observable photon properties, emphasizing measurement context.

Findings

Entangling interactions can be transformed into observable photon entanglement.

Measurement context critically influences quantum optical entanglement.

Potential for new quantum information protocols using entangled field modes.

Abstract

The question of whether entanglement between photons is equivalent to entanglement between their characteristic field modes, specifically, the single-particle wavefunctions that are composed and superposed to describe particles in such modes, is a key, open problem concerning multi-partite optical degrees of freedom, and has profound implications for topics ranging from quantum foundations to quantum computation. Here, I offer a fresh, deeper, physical insight into this subtle, albeit enduring, issue by describing a situation in which the entangling interactions between optical modes, namely, the wavefunctions, can be distilled into genuine entanglement between the physical, observable properties of the photons, which are the wavefunctional degrees of freedom. This theoretical observation also highlights the salience of the measurement context, especially, of clearly disambiguating between the choice of the quantum subsystem and the decision to measure an observable along a particular axis of measurement, while quantifying and transforming quantum optical entanglement. This theoretical observation might be applied to formulate a new class of protocols for performing quantum information tasks, using entangled photons within inseparable field modes.