Complete orbital angular momentum Bell-state measurement and superdense coding

TL;DR

This paper demonstrates the first complete measurement of orbital angular momentum Bell states using linear optics, enabling superdense coding with higher channel capacity in quantum communication.

Contribution

It introduces a novel method for complete OAM Bell-state measurement using linear optics, overcoming previous limitations and enhancing quantum information processing capabilities.

Findings

Achieved complete OAM Bell-state measurement in a single subspace.

Realized superdense coding with ~82% success probability.

Increased channel capacity to approximately 1.1 bits.

Abstract

Quantum protocols require access to large-scale entangled quantum states, due to the requirement of channel capacity. As a promising candidate, the high-dimensional orbital angular momentum (OAM) entangled states have been implemented, but only one of four OAM Bell states in each individual subspace can be distinguished. Here we demonstrate the first realization of complete OAM Bell-state measurement (OAM-BSM) in an individual subspace, by seeking the suitable unitary matrix performable using only linear optics and breaking the degeneracy of four OAM Bell states in ancillary polarization dimension. We further realize the superdense coding via our complete OAMBSM with the average success probability of ~82% and the channel capacity of ~1.1(4) bits. This work opens the window for increasing the channel capacity and extending the applications of OAM quantum states in quantum information in future.