Sökning: "perturbative expansion"

Hittade 5 uppsatser innehållade orden perturbative expansion.

  1. 1. Green's Functions Investigations in Quantum Transport Geometries

    Master-uppsats, Lunds universitet/Matematisk fysik; Lunds universitet/Fysiska institutionen

    Författare :Philip Johansson; [2022]
    Nyckelord :Quantum transport; Green s functions; self-energy; non-equilibrium; many-body physics; Physics and Astronomy;

    Sammanfattning : In this thesis we employ the non-equilibrium Green’s function (NEGF) method to study both finite and infinite systems. We develop a codebase capable of computing the steady state interacting NEGF in open systems, i.e. LÄS MER

  3. 2. Conformal field theory at large N

    Master-uppsats, Uppsala universitet/Teoretisk fysik

    Författare :Nadia Flodgren; [2019]
    Nyckelord :Conformal field theory; conformal bootstrap; large N; anti-de Sitter; anomalous dimension; AdS CFT correspondence;

    Sammanfattning : The conformal bootstrap method is a non-perturbative method that uses the symmetry in a conformal field theory to constrain and solve for the observables in the theory. We consider a conformal field theory with the symmetry group SU(N) and four general scalar fields as the only low dimensional operators. LÄS MER

  4. 3. The kaon electromagnetic mass difference in AdS/QCD

    Master-uppsats, Lunds universitet/Teoretisk partikelfysik - Geonomgår omorganisation; Lunds universitet/Institutionen för astronomi och teoretisk fysik - Genomgår omorganisation

    Författare :Jack Borthwick; [2016]
    Nyckelord :particle physics; AdS QCD; AdS CFT; kaon; electromagnetic mass difference; quantum field theory; Physics and Astronomy;

    Sammanfattning : In this thesis, a holographic model for quantum chromodynamics (QCD) is used to estimate the electromagnetic contribution to the kaon mass difference. The principal ideas of the model are inspired by the AdS/CFT correspondence, which is believed to be exact. LÄS MER

  5. 4. 3+1 Approach to Cosmological Perturbations : Deriving the First Order Scalar Perturbations of the Einstein Field Equations

    Kandidat-uppsats, Karlstads universitet/Fakulteten för hälsa, natur- och teknikvetenskap (from 2013)

    Författare :Söderkvist Vermelin Wilhelm; [2016]
    Nyckelord :physics; astronomy; theoretical physics; perturbation; cosmology; cosmological perturbations; 3 1 formalism; first order perturbation; perturbation theory; universe; fysik; astronomi; teoretisk fysik; störning; störningsräkning; kosmologi; kosmologiska störningar; kosmologisk störningsräkning; 3 1 formalismen; första ordningens störningar; störningsteori; universum;

    Sammanfattning : Experimental data suggest that the universe is homogeneous and isotropic on sufficiently large scales. An exact solution of the Einstein field equations exists for a homogeneous and isotropic universe, also known as a Friedmann-Lemaître-Robertson-Walker (FLRW) universe. LÄS MER

  7. 5. Matrix Integrals : Calculating Matrix Integrals Using Feynman Diagrams

    Kandidat-uppsats, Uppsala universitet/Teoretisk fysik

    Författare :Adam Friberg; [2014]
    Nyckelord :fat graph; feynman diagram; matrix integral; perturbative expansion; wick s theorem;

    Sammanfattning : In this project, we examine how integration over matrices is performed. We investigate and develop a method for calculating matrix integrals over the set of real square matrices. LÄS MER