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

TL;DR

This study extends quantum electrodynamical density functional theory with optimized effective potential to include continuous photon modes, demonstrating its effectiveness in modeling dissipative electron-photon interactions and spontaneous emission.

Contribution

It introduces a generalized OEP formalism for QEDFT with continuous photon modes and validates its capability to capture dissipative electron-photon dynamics in lossy cavities.

Findings

OEP-QEDFT accurately models spontaneous emission.

The method performs well with Lorentzian and Ohmic spectral densities.

Good qualitative and quantitative agreement in dissipative regimes.

Abstract

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