Searcharxiv⌕ Search

arXiv subjects

Guillermo Hansen

Publications and source records attributed to Guillermo Hansen.

2 recordsLinked to original sources
arXiv2025

QED positronium and the exact renormalization group

Quantum electrodynamics (QED) is studied in the framework of the exact (functional) renormalization group (ERG). This is done using an approach to these equations which employs dimensional regularization. Simultaneous solutions of the ERG equations and Ward identities are considered. An approach to the study of bound states at long distances in the ERG is employed to describe the positronium. This is done by introducing a real scalar field which describes that bound state. The flow equations are studied using an effective action ansatz and a low-momentum expansion.

hep-ph↗
arXiv2025

On the Sign of the Casimir Force Between Two Bodies Coupled to a Dirac field

We apply the result of Kenneth and I. Klich, Phys. Rev. Lett.97, 160401 (2006) to derive a theorem for two objects coupled to a Dirac field. We demonstrate that a sufficient condition for the Casimir interaction to be repulsive, is for their geometric configuration to be odd under the same reflection operation considered in that work.

hep-th↗