We experimentally investigate the properties of hyperentangled states displaying simultaneous entanglement in multiple degrees of freedom, and find that Bell tests beyond the standard Clauser, Horne, Shimony, Holt inequality can reveal a higher-dimensional nature in a device-independent way. Specifically, we show that hyperentangled states possess more than just simultaneous entanglement in separate degrees of freedom but also entanglement in a higher dimensional Hilbert space. We also verify the steerability of hyperentangled quantum states by steering different photonic degrees of freedom.
@article{arxiv.2207.09990,
title = {Entanglement Verification of Hyperentangled Photon Pairs},
author = {Christopher K. Zeitler and Joseph C. Chapman and Eric Chitambar and Paul G. Kwiat},
journal= {arXiv preprint arXiv:2207.09990},
year = {2022}
}