An Interacting-Response Constraint for Photon Density Functionals
Abstract
When the coupling to a quantized field becomes weak, the leading term of the photon exchange--correlation action depends on the fluctuations of the interacting electronic system, not those of a density-matched noninteracting reference. We establish this requirement by proposing an adiabatic connection formulation of electron-photon coupling at fixed electronic density and controlling the density derivatives. Approximating the response in the integral yields a ring functional in terms of the Kohn--Sham response and electronic kernel. Exact model tests verify fourth-order rather than second-order errors. In a two-electron Hubbard dimer, the functional correctly predicts a correlation-induced polarization reversal, while two Kohn--Sham photon prescriptions don't. In an interacting quantum-dot resonator model with electron injection and escape, the functional recovers resonant photon-assisted transport missed by two Kohn--Sham photon prescriptions.
Related
- Dysfunctional Functionals and their Therapies in Time-Dependent Density Functional Theory
- Electron-Density-Informed Molecular Property Prediction Using Surrogate Functionals
- Normal-ordered perturbative expansion for matter systems interacting with continuous-mode quantum photon fields
- Density functionals for the Pauli-Fierz Hamiltonian
- HOMO-LUMO Intervals from Modern Density Functionals as Fundamental Gap Estimators
BibTeX
@misc{zhang2026interactingresponse,
title = {{An Interacting-Response Constraint for Photon Density Functionals}},
author = {Xiaoyu Zhang},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2608.22995},
eprint = {2608.22995},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.22995},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - UNPB
TI - An Interacting-Response Constraint for Photon Density Functionals
AU - Xiaoyu Zhang
PY - 2026
DA - 2026/11/03
PB - arXiv
DO - 10.48550/arxiv.2608.22995
UR - https://arxiv.org/abs/2608.22995
AB - When the coupling to a quantized field becomes weak, the leading term of the photon exchange--correlation action depends on the fluctuations of the interacting electronic system, not those of a density-matched noninteracting reference. We establish this requirement by proposing an adiabatic connection formulation of electron-photon coupling at fixed electronic density and controlling the density derivatives. Approximating the response in the integral yields a ring functional in terms of the Kohn--Sham response and electronic kernel. Exact model tests verify fourth-order rather than second-order errors. In a two-electron Hubbard dimer, the functional correctly predicts a correlation-induced polarization reversal, while two Kohn--Sham photon prescriptions don't. In an interacting quantum-dot resonator model with electron injection and escape, the functional recovers resonant photon-assisted transport missed by two Kohn--Sham photon prescriptions.
ER -