On-chip generation and collectively coherent control of the superposition of the whole family of Dicke states

Integrated quantum photonics has recently emerged as a powerful platform for generating, manipulating, and detecting entangled photons. Multipartite entangled states lie at the heart of the quantum physics and are the key enabling resources for scalable quantum information processing. Dicke state is an important class of genuinely entangled state, which has been systematically studied in the light-matter interactions, quantum state engineering and quantum metrology. Here, by using a silicon photonic chip, we report the generation and collectively coherent control of the entire family of four-photon Dicke states, i.e. with arbitrary excitations. We generate four entangled photons from two micro-resonators and coherently control them in a linear-optic quantum circuit, in which the nonlinear and linear processing are achieved in a micrometer-scale device. The generated photons are in telecom band, which lays the groundwork for large-scale photonic quantum technologies for multiparty networking and metrology.