LAUSR

Radiative coupling creates an entangled state between two silicon vacancies in diamond A deterministic interface between a single atom and a single optical photon is the essential building block underpinning many quantum applications of light for quantum communication, sensing, and simulations. Light and matter interact weakly with each other, so the challenge is to create conditions enabling strong interactions. Fortunately, solid-state quantum photonics has matured dramatically, and it is possible to create artificial photonic nanostructures that markedly enhance light-matter coupling. Moreover, single atoms, which are cumbersome to control experimentally because they need to be trapped and cooled, can be replaced by solid-state quantum emitters such as vacancy centers in diamond, molecules, or quantum dots (1, 2). The high quality and purity of these systems now imply that coherent and near-deterministic photon-emitter interfaces are routinely constructed (2), but it is still challenging to scale up and deterministically couple multiple quantum emitters. On page 662 of this issue, Evans et al. (3) report on the successful coupling of two diamond silicon vacancy (SiV) quantum emitters mediated by their mutual coupling to a nanophotonic cavity. Radiative coupling leads to the formation of an entangled state between the two emitters (see the figure).