Heidelberg 2022 – wissenschaftliches Programm

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MP: Fachverband Theoretische und Mathematische Grundlagen der Physik

MP 4: Quantum field theory, AdS/CFT, non-equilibrium and quantum dynamics

MP 4.5: Vortrag

Dienstag, 22. März 2022, 17:35–17:55, MP-H5

Electrons and their interactions: A deduction from Quantum Field Theory — •Nadine Cetin and Nils Schopohl — Institut für Theoretische Physik, Universität Tübingen, Auf der Morgenstelle 14, 72076 Tübingen

We suggest a new unitary transformation of the fundamental electron-positron field theory Hamiltonian of Quantum Electrodynamics (QED), that brings with help of Wegner’s flow equation method this Hamiltonian to a block-diagonal form, each block labeled by an eigenvalue of the operator N=N^(e)+N^(p) , with N^(e) counting the number of electrons and N^(p) counting the number of positrons, while keeping all interactions with with long wavelength photons λ_ph≫h/m_ec intact. A representation of that block-diagonal Hamiltonian as a perturbation series with regard to the fine structure constant α_FS≈1/137 establishes to order α_FS² the well known gauge invariant and particle number conserving Hamiltonian for nonrelativistic electrons and positrons in its second quantized guise. Our derivation of the effective two-particle interactions between particles carrying mass, charge and spin while moving at nonrelativistic speed arises directly from QED throughout treating electron fields and positron fields in an entire symmetrical fashion. Similarities and salient contrast with related early work of Cohen-Tannoudji et al., Takashi Itoh and I. Bialynicki-Birula are discussed in detail.