Dissipation and spontaneous emission in quantum electrodynamical density functional theory based on optimized effective potential: A proof of concept study

We generalize the optimized effective potential (OEP) formalism in quantum electrodynamical density functional theory (QEDFT) to case of continuous distribution photon modes, and study its applicability dissipative dynamics electron systems interacting with photons lossy cavities. Specifically, we test whether this technique is capable capturing features electron-photon interaction related spontaneous emission corresponding energy transfer from electrons cavity photons. For purpose, analyze a discrete three-site system one coupled cavity, which, fact, minimal model allowing eliminate classical radiation loss, but still have nontrivial dynamics. By considering two typical spectral densities modeling (i) Lorentzian broadening peaks, (ii) Ohmic bath, several representative dynamical regimes, find that OEP-QEDFT demonstrates good qualitative quantitative performance, especially when disspation dominated by one-photon processes.