Observation of scalable and deterministic multi-atom Dicke states in an atomic vapor

Dicke state is fundamentally responsible for many intriguing collective behaviors of many-body systems. To experimentally study how a property of multi-particle states scales with the number of particles, it is essential to have the capability of preparing and measuring multi-particle states with scalable and deterministic number of particles. We report the first observation of Dicke states consisting of two to seven atoms in an atomic vapor by using optical two-dimensional coherent spectroscopy. The unique capability to selectively access specific multi-atom Dicke states in atomic vapors can enable new studies of many-body physics in the presence of thermal motion and offer new opportunities to utilize multi-atom Dicke states for quantum information processing.