Hyperentanglement-empowered intelligent quantum optics

Hyperentanglement, a sophisticated form of quantum entanglement generated across multiple degrees of freedom (DOFs) such as polarisation, spatial modes, orbital angular momentum, spin angular momentum, time-bin and frequency, has the potential to significantly advance quantum technologies. This review explores the recent advances in hyperentanglement research in the last few years, focusing on its applications in quantum communication, sensing and computing. We focus on key aspects such as hyperentanglement generation and manipulation, while discussing the challenges and opportunities for scaling these technologies towards practical quantum devices. A major challenge is accurately manipulating the properties of optical nanodevices to allow for optimal hyperentanglement generation and we discuss the use of machine learning to enhance this process will be discussed as an emerging approach. Furthermore, we examine the impact of using advanced nanotechnology for hyperentanglement generation to transform fields like medicine, defence technology and different physics applications.