A variant of the quantum electrodynamics (QED) suited for analyzing nanoparticles and quantum energy exchanges between them was described in [Phys.Rev.B(92), pp.035128(2015); Phys.Rev.B(93), 075151(2016); Phys.Rev.B(94),pp.085133(2016)].
A variant of QED to describe strong, ultrastrong, and deep-strong coupling regimes is described in [Phys.Rev.A(102),pp.013701(2020)]
A variant of superradiance theory suited for tunable, nanoparticle thermal emitter assemblies is described in [Phys.Rev.B(95),pp.155443(2017); Phys.Rev.B(97),pp.125406(2017)]