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Hittade 3 uppsatser som matchar ovanstående sökkriterier.

  1. 1. Asymptotic Symmetries and Dressed States in QED and QCD

    Master-uppsats, Stockholms universitet/Fysikum

    Författare :Saimeng Zhou; [2023]
    Nyckelord :Dressed states; Large gauge transformation; Faddeev-Kulish formalism; Generalized coherent state operator; Wilson line; Infrared divergence; Asymptotic Hamiltonian; QED; QCD;

    Sammanfattning : Infrared divergences arising in theories with massless gauge bosons have been shown to cancel in scattering amplitudes when using dressed states constructed from the Faddeev- Kulish approach to the asymptotic states. It has been established that these states are closely related to asymptotic symmetries of the theory, that is, non-vanishing gauge trans- formations at the asymptotic boundary. LÄS MER

  3. 2. Generalized Abelian Gauge Theory & Generalized Global Symmetry

    Master-uppsats, Uppsala universitet/Teoretisk fysik

    Författare :Emil Hössjer; [2020]
    Nyckelord :Differential characters; Wilson lines; generalized global symmetry; BF theory; Maxwell theory; spontaneous symmetry breaking; intersection number; selection rules; Noether theorem; sphere bundle; t Hooft operator;

    Sammanfattning : We study Cheeger-Simons differential characters in order to define higher form U(1) gauge fields and their Wilson lines. We then go on to define generalized global symmetries. This is a topological formulation of symmetries which has interesting consequences when the charged operators extend through space. LÄS MER

  4. 3. Asymptotic Symmetries and Faddeev-Kulish states in QED and Gravity

    Master-uppsats, Stockholms universitet/Fysikum

    Författare :David Gaharia; [2019]
    Nyckelord :Faddeev-Kulish; BMS; Bondi-Metzner-Sachs; Asymptotic Symmetries; Asymptotic States; Wilson Lines; Infrared Divergence; Bloch-Nordsieck; Large Gauge Transformations; Fock; QED; Quantum Electrodynamics; Perturbative Quantum Gravity; PQG; U 1 ; Transformations; Mandelstam Quantization;

    Sammanfattning : When calculating scattering amplitudes in gauge and gravitational theories one encounters infrared (IR) divergences associated with massless fields. These are known to be artifacts of constructing a quantum field theory starting with free fields, and the assumption that in the asymptotic limit (i.e. LÄS MER