Feynman Diagrams for Dispersion Interactions Out of Equilibrium -- Two-Body Potentials for Atoms with Initial Excitation

Abstract

Diagrammatic techniques are well-known in the calculation of dispersion interactions between atoms or molecules. The multipolar coupling scheme combined with Feynman ordered diagrams significantly reduces the number of graphs compared to elementary stationary perturbation theory. We review calculations of van der Waals-Casimir-Polder forces, focusing on two atoms or molecules one of which is excited. In this case, calculations of the corresponding force are notorious for mathematical issues connected to the spontaneous decay of the excitation. Treating such unstable states in a full non-equilibrium theory provides a physical interpretation of apparent contradictions in previous results and underlines the importance of decay processes for the intermolecular potential. This may have important implications on reactions in biological systems, where excited states may be relatively long-lived and the resonant intermolecular force may result in directed Brownian motion.

Proceedings of Quantum Field Theory under External Conditions (QFExt) 2011

References in corpus (6)

• JaxoDraw: A graphical user interface for drawing Feynman diagrams. Version 2.0 release notes
• Thermal Casimir-Polder shifts in Rydberg atoms near metallic surfaces
• Van der Waals interaction of excited media
• Casimir-Polder interaction between an excited atom and a gas dielectric medium
• Dynamics of thermal Casimir-Polder forces on polar molecules
• Interaction of a Bose-Einstein condensate with a surface: perturbative S-matrix approach

Cited by in corpus (6)

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• Van der Waals interactions between excited atoms in generic environments
• Modified and controllable dispersion interaction in a 1D waveguide geometry
• Two-atom interaction energies with one atom in an excited state: van der Waals potentials vs. level shifts
• Resonance oscillations of non-reciprocal long-range van der Waals forces between atoms in electromagnetic fields