Dynamics of Many-Emitter Ensembles: Probing Cooperative Evolution with Scalable Quantum Circuits

Abstract: Many-particle quantum systems often give rise to exotic behaviors in their nonequilibrium dynamics that are rather challenging to reveal with analytical methods or with classical computation. Here, we consider the case of a system of many quantum emitters coupled through a radiation bath. By adopting an efficient mapping of the bosonic modes onto a set of quantum bits, we implement quantum circuits, compatible with NISQ (Noisy Intermediate-Scale Quantum) era systems, that allow us to investigate the dynamics of the ensemble as a function of various parameters, including the number of emitters, the spectral inhomogeneity in the system, the emission lifetime of independent emitters, and the spatial separation between emitters. The quantum algorithms afford us the capacity to precisely track the emergence of cooperative dynamics, manifested through superradiant emission, as the system is tuned towards optimal coupling with respect to various parameters. We are particularly able to characterize superradiant emission in an inhomogeneous ensemble as a function of the linewidth of the individual emitters. These quantum algorithms avoid approximations performed in conventional studies of many-emitter systems and provide a robust and intuitive characterization. Despite being limited to a small number of qubits, the present calculations are found to provide a reliable characterization validated by comparison with analytical solutions and classical computation results in their respective regimes of validity. These findings indicate that the approach can be employed to effectively simulate a broad variety of many-emitter systems.