Self-consistent radiative backaction in dispersion interactions: a minimal mQED model

TL;DR

This paper develops a self-consistent quantum electrodynamics model to study how electromagnetic backaction alters van der Waals interactions, revealing long-range effects absent in traditional fixed-spectrum theories.

Contribution

It introduces a minimal self-consistent mQED framework that accounts for backaction effects, extending the understanding of dispersion interactions beyond fixed spectra assumptions.

Findings

Self-consistent backaction can cause long-range modifications of van der Waals forces.

One-sided self-energy effects are short-ranged, unlike full backaction.

Repeated photon scattering leads to coherent accumulation affecting interactions.

Abstract

Dispersion interactions are usually derived assuming fixed internal spectra of the interacting quantum systems. Here, we relax this assumption and study how self-consistent electromagnetic backaction modifies van der Waals interactions when excitation energies and transition dipole moments are allowed to respond to the interaction itself. Within a macroscopic quantum electrodynamics framework, we formulate a self-consistent treatment that includes both self-energy corrections and mutual backaction. Using a minimal three-level model, we show that, while one-sided self-energy effects are short-ranged, fully self-consistent backaction can lead to substantial, long-ranged modifications of the effective van der Waals interaction. Our analysis demonstrates that these effects originate from the coherent accumulation of repeated photon-mediated scattering processes. The results highlight limitations of perturbative dispersion theories with fixed spectra and identify few-level systems as a clean platform for studying backaction in dispersion forces.