Entanglement Verification of Hyperentangled Photon Pairs

We experimentally investigate the properties of hyperentangled states displaying simultaneous entan-glement 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. Specifi-cally, 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.

Automated summary

In this study, we experimentally investigate the properties of hyperentangled states with simultaneous entanglement in multiple degrees of freedom. We find that Bell tests beyond the standard inequality can reveal the higher-dimensional nature of hyperentangled states in a device-independent manner. Our results demonstrate the existence of entanglement in a higher-dimensional Hilbert space, in addition to simultaneous entanglement in separate degrees of freedom.