Bosonic superradiance and subradiance in an array of superconducting transmon devices

Multiple atoms coherently interacting with electromagnetic modes can give rise to collective effects, namely superradiance and subradiance. Most of the research on these topics has focused on two-level systems. Recent experimental progress in realizing large arrays of superconducting transmon devices with multiple excitations embedded inside a waveguide motivated us to extend the formalism developed by Lalumiere et al. [1] to multilevel interacting bosonic systems. Analytical and numerical analysis of the eigenvalues and eigenstates of the effective non-Hermitian Bose-Hubbard Hamiltonian reveals an enhanced superradiance arising from the bosonic nature of transmon excitations. The validity of the bosonic model as well as the existence of collective effects in this system are verified by studying the transmission of radiation both experimentally and numerically.
[1] K. Lalumiere et al., Phys. Rev. A 88, 043806 (2013)