Quantum Metasurfaces for Photonic Many-Body Entanglement

Entanglement generation is a crucial ingredient for the realization of future quantum technologies, and requires high fidelity quantum gates between atomic and photonic qubits. I will describe the novel concept of quantum metasurfaces which allows for the generation of large-scale atom-photon entanglement, hence constituting a new platform for manipulating both classical and quantum properties of light. These quantum metasurfaces are realized by preparing and manipulating entangled states of atomic arrays which scatter or emit light. I will show that this platform allows for multi-qubit gates between atomic and photonic qubits, and for the generation of photonic GHZ states and highly entangled states suitable for quantum information processing. I will discuss potential experimental realizations and possible new applications. Finally, I will briefly describe an experimental effort to realize large-scale entanglement with atom-like defects in nanophotonic cavities.