Observation of Genuine High-dimensional Multi-partite Non-locality in Entangled Photon States

TL;DR

This paper demonstrates the experimental creation of high-dimensional, multi-partite entangled photon states that violate local-hidden-variable theories, advancing quantum communication and computing capabilities.

Contribution

It presents the first experimental realization of multi-partite high-dimensional GHZ states using path and polarization encoding, surpassing qubit limitations.

Findings

Successfully prepared three- and four-particle high-dimensional GHZ states.

Demonstrated violation of local-hidden-variable theories with high-dimensional systems.

Showed potential for enhanced quantum communication and computing protocols.

Abstract

Quantum information science has leaped forward with the exploration of high-dimensional quantum systems, offering greater potential than traditional qubits in quantum communication and quantum computing. To advance the field of high-dimensional quantum technology, a significant effort is underway to progressively enhance the entanglement dimension between two particles. An alternative effective strategy involves not only increasing the dimensionality but also expanding the number of particles that are entangled. We present an experimental study demonstrating multi-partite quantum non-locality beyond qubit constraints, thus moving into the realm of strongly entangled high-dimensional multi-particle quantum systems. In the experiment, quantum states were encoded in the path degree of freedom (DoF) and controlled via polarization, enabling efficient operations in a two-dimensional plane to prepare three- and four-particle Greenberger-Horne-Zeilinger (GHZ) states in three-level systems. Our experimental results reveal ways in which high-dimensional systems can surpass qubits in terms of violating local-hidden-variable theories. Our realization of multiple complex and high-quality entanglement technologies is an important primary step for more complex quantum computing and communication protocols.