YangMills driven Cosmic Expansion
(2016) FYTM03 20161Theoretical Particle Physics
Department of Astronomy and Theoretical Physics
 Abstract
 This thesis will investigate the possibility to have SU(2) gauge fields as the source to the Cosmic Inflation and/or to the Dark Energy.
It will be explained that, under certain conditions, the Universe can be filled with vector fields without violating its isotropy. Those conditions are naturally fulfilled within the SU(2) gauge theory.
Both Einstein's equations and the equations of motion for the fields will be found from the first principles. The equations will be used to show that classical SU(2) gauge fields behave as radiation and can therefore not cause an exponential expansion. But when vacuum polarizations is taken into account the fields, in the oneloop approximation, behave as a constant energy density which indeed can... (More)  This thesis will investigate the possibility to have SU(2) gauge fields as the source to the Cosmic Inflation and/or to the Dark Energy.
It will be explained that, under certain conditions, the Universe can be filled with vector fields without violating its isotropy. Those conditions are naturally fulfilled within the SU(2) gauge theory.
Both Einstein's equations and the equations of motion for the fields will be found from the first principles. The equations will be used to show that classical SU(2) gauge fields behave as radiation and can therefore not cause an exponential expansion. But when vacuum polarizations is taken into account the fields, in the oneloop approximation, behave as a constant energy density which indeed can drive an exponential expansion of the Universe.
First order perturbations in classical SU(2) gauge fields and in the spacetime will be considered. The main purpose for that is to put up a framework in which it is possible to extract predictions of how the fluctuations in the energy density would be distributed over space. Firstly, it will be shown that for perturbations in the framework of Chaotic Inflation there is only one degree of freedom; one invariant combination of the perturbations in the spacetime. The invariant combinations for classical SU(2) gauge fields has not been found in this theses but it is shown that neither the invariant in the Chaotic Inflation nor the Bardeen variables are invariant for those fields.
The fluctuations in the energy density will be calculated numerically in the synchronous gauge for classical SU(2) gauge fields. The result shows that there will be an energy transfer from the homogeneous part of the fields to the fluctuations; both in the fields themselves and in the spacetime. Since in a full quantum description the fluctuations correspond to particles, this describes a mechanism for particle production. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/studentpapers/record/8881076
 author
 Ljungberg, Jimmy ^{LU}
 supervisor

 Roman Pasechnik ^{LU}
 organization
 course
 FYTM03 20161
 year
 2016
 type
 H2  Master's Degree (Two Years)
 subject
 keywords
 Cosmic Inflation, Dark Energy, YangMills, SU(2) gauge fields, Perturbations
 language
 English
 id
 8881076
 date added to LUP
 20160622 16:46:31
 date last changed
 20161115 13:56:31
@misc{8881076, abstract = {This thesis will investigate the possibility to have SU(2) gauge fields as the source to the Cosmic Inflation and/or to the Dark Energy. It will be explained that, under certain conditions, the Universe can be filled with vector fields without violating its isotropy. Those conditions are naturally fulfilled within the SU(2) gauge theory. Both Einstein's equations and the equations of motion for the fields will be found from the first principles. The equations will be used to show that classical SU(2) gauge fields behave as radiation and can therefore not cause an exponential expansion. But when vacuum polarizations is taken into account the fields, in the oneloop approximation, behave as a constant energy density which indeed can drive an exponential expansion of the Universe. First order perturbations in classical SU(2) gauge fields and in the spacetime will be considered. The main purpose for that is to put up a framework in which it is possible to extract predictions of how the fluctuations in the energy density would be distributed over space. Firstly, it will be shown that for perturbations in the framework of Chaotic Inflation there is only one degree of freedom; one invariant combination of the perturbations in the spacetime. The invariant combinations for classical SU(2) gauge fields has not been found in this theses but it is shown that neither the invariant in the Chaotic Inflation nor the Bardeen variables are invariant for those fields. The fluctuations in the energy density will be calculated numerically in the synchronous gauge for classical SU(2) gauge fields. The result shows that there will be an energy transfer from the homogeneous part of the fields to the fluctuations; both in the fields themselves and in the spacetime. Since in a full quantum description the fluctuations correspond to particles, this describes a mechanism for particle production.}, author = {Ljungberg, Jimmy}, keyword = {Cosmic Inflation,Dark Energy,YangMills,SU(2) gauge fields,Perturbations}, language = {eng}, note = {Student Paper}, title = {YangMills driven Cosmic Expansion}, year = {2016}, }