Spontaneous emission from correlated emitters

Spontaneous emission is a fundamental quantum phenomenon whereby an electron transitions to a lower energy state while emitting a photon, manifesting across a plethora of fields from atomic physics and solid-state physics to astrophysics. Despite its ubiquity, there remain fundamental unanswered questions about spontaneous emission from systems with quantum correlations. Quantum correlations have become a critical resource in all platforms of quantum information science, such as coupled quantum dots and atomic arrays, enabling observations of previously elusive effects like super- and subradiance. Despite its significance, many aspects of spontaneous emission from correlated emitters remain unresolved. Here, we find the quantum-optical state of light spontaneously emitted from systems with arbitrary quantum correlations. We show under what conditions the correlations are not lost during the spontaneous emission but instead, transfer to the output light. The process of spontaneous emission can then create desired photonic states such as squeezed and Schrodinger-cat states. Our work captures the multi-mode nature of super- and subradiance and shows the roles of emitter locations, losses, and beyond-Markov dynamics on the emitted quantum state of light. We present manifestations of these effects in both cavity- and waveguide-QED. Our findings suggest new paths for creating and manipulating multi-photon quantum light for bosonic codes in continuous-variable-based quantum computation, communications, and sensing.