Sökning: "friedmann equation"

Hittade 5 uppsatser innehållade orden friedmann equation.

  1. 1. General Relativity and Dynamical Universes

    Kandidat-uppsats, Uppsala universitet/Teoretisk fysik

    Författare :Kajsa Fransson; [2021]
    Nyckelord :cosmology; general relativity; scale factor; friedmann equation;

    Sammanfattning : The aim of this report is to explore different models of cosmology, depending on components as matter, radiation and dark energy. To be able to investigate the behaviour and age of these model universes, it is necessary to solve the Friedmann equation. LÄS MER

  3. 2. When Braneworlds Collide

    Master-uppsats, Uppsala universitet/Teoretisk fysik

    Författare :Toivo Tuma Niemi; [2021]
    Nyckelord :physics; cosmology; parallel universe; dark energy; inflation; braneworlds; D brane;

    Sammanfattning : This project is an investigation of a cosmological model consisting of a five dimensional AdS-vacuum with a flux. By discharges in the flux, four dimensional bubbles can nucleate in the vacuum and collide with each other while expanding. Our observable universe is considered to be localized on the membrane of such a bubble. LÄS MER

  4. 3. Spherically Symmetric Gravitational Collapse

    Kandidat-uppsats, Lunds universitet/Teoretisk partikelfysik - Geonomgår omorganisation

    Författare :Lucas Bring; [2021]
    Nyckelord :gravitational collapse; gravitation; general relativity; black hole; Schwarzschild coordinates; Gullstrand-Painleve coordinates; Friedmann-Robertson-Walker metric; finite-time collapse; Physics and Astronomy;

    Sammanfattning : This thesis presents a derivation of the equation of motion of particles in a dust star, as it undergoes collapse. This is done by finding exact solutions to the Einstein field equations. We follow the original work by Oppenheimer and Snyder, starting from the general spherically symmetric metric in comoving coordinates. LÄS MER

  5. 4. Decay of solutions to the Klein-Gordon equation on some expanding cosmological spacetimes

    Master-uppsats, Lunds universitet/Teoretisk partikelfysik - Geonomgår omorganisation

    Författare :Amol Sasane; [2019]
    Nyckelord :Klein-Gordon equation; general relativity; FLRW models; Schwarzschild-de Sitter; Reissner-Nordström-de Sitter; Physics and Astronomy;

    Sammanfattning : The decay of solutions to the Klein-Gordon equation is studied in two expanding cosmological spacetimes, namely (1) the de Sitter universe in flat Friedmann-Lemaitre-Robertson-Walker (FLRW) form, and (2) the cosmological region of the Reissner-Nordström-de Sitter (RNdS) model. Using energy methods, for initial data with finite higher order energies, bounds on the decay rates of the solution are obtained. LÄS MER

  7. 5. Aspects of spatially homogeneous and isotropic cosmology

    Kandidat-uppsats, Fakulteten för teknik- och naturvetenskap

    Författare :Mikael Isaksson; [2011]
    Nyckelord :Cosmology; Spatially; homogeneous; isotropic; universe; Friedmann-Lemaître; Einstein s field equation; Robertson-Walker;

    Sammanfattning : In this thesis, after a general introduction, we first review some differential geometry to provide the mathematical background needed to derive the key equations in cosmology. Then we consider the Robertson-Walker geometry and its relationship to cosmography, i.e., how one makes measurements in cosmology. LÄS MER