Extreme and Entangled Light

Gerardo Adesso, Steve Campbell, Fabrizio Illuminati +1 more

We study state engineering through bilinear interactions between two remote qubits and two-mode gaussian light fields. The attainable two-qubit states span the entire physically allowed region in the entanglement-versus-global-purity plane. Two-mode gaussian states with maximal entanglement at fixed global and marginal entropies produce maximally entangled two-qubit states in the corresponding entropic diagram. We show that a small set of parameters characterizing extremally entangled two-mode gaussian states is sufficient to control the engineering of extremally entangled two-qubit states, which can be realized in realistic matter-light scenarios.

Angus Crookes, Ben Yuen, Stephen M. Hanham +1 more

Multi-partite entanglement is fundamental to emerging quantum technologies, such as quantum networks, which ultimately require devices with strong light–matter interactions and long coherence times. Here, we introduce nanobeam photonic crystal cavities combining both extreme quality factors (∼107) with sub-wavelength field confinement to reach unprecedented light–matter interactions. Operating at 780 nm, our devices are tailored for efficient coupling and entanglement with ultracold 87Rb atoms, a key ingredient in quantum networks due to their hyperfine structure. Our new designs also facilitate the precise optical trapping of atoms, and we demonstrate coherent entanglement generation between them, which is remarkably resilient to atomic displacements. These platforms can be easily scaled-up to extremely large quantum networks, for distributed quantum computing and future light-based quantum technologies.

Andrew Forbes, Andrea Aiello, Bienvenu I. Ndagano

Gerardo Adesso, Steve Campbell, Fabrizio Illuminati +1 more