Diffraction-induced entanglement loss of orbital-angular-momentum states

TL;DR

This paper derives an analytical formula describing how diffraction causes entanglement loss in orbital angular momentum bi-photon states when they encounter an obstacle, highlighting the role of mode overlap.

Contribution

It introduces a new analytical expression linking diffraction-induced mode overlap to entanglement decay in OAM states, advancing understanding of quantum state robustness.

Findings

Entanglement decay is governed by diffraction-induced mode overlap.

Decay depends on the size and position of the obstruction.

Analytical expression quantifies the entanglement loss process.

Abstract

We provide an analytical expression for the entanglement decay of initially maximally entangled orbital angular momentum bi-photon states, when scattered off an obstruction. We show that the decay is controlled by the diffraction-induced mutual overlap between the diffracted field modes, and quantify its dependence on the size and position of the obstruction.