Zobrazeno 1 - 10
of 35
pro vyhledávání: '"Thorsrud, Mikjel"'
Publikováno v:
Class. Quantum Grav. 37 (2020) 065015
We investigate a corner of the Bianchi models that has not received much attention: "extended FLRW models" (eFLRW) defined as a cosmological model with underlying anisotropic Bianchi geometry that nevertheless expands isotropically and can be mapped
Externí odkaz:
http://arxiv.org/abs/1911.05793
Why is the Universe so homogeneous and isotropic? We summarize a general study of a $\gamma$-law perfect fluid alongside an inhomogeneous, massless scalar gauge field (with homogeneous gradient) in anisotropic spaces with General Relativity. The anis
Externí odkaz:
http://arxiv.org/abs/1909.11965
Autor:
Thorsrud, Mikjel
Publikováno v:
Class. Quantum Grav. 36 (2019) 235014
We scrutinize the overall structure of the space of cosmological models of Bianchi type I-VII$_h$ that contain a free massless scalar field, with a spatially homogeneous gradient $\nabla_\mu \varphi$ that generally breaks isotropy, in addition to a s
Externí odkaz:
http://arxiv.org/abs/1905.11456
Publikováno v:
Class. Quantum Grav. 35 (2018) 095004
In this paper the dynamics of free gauge fields in Bianchi type I-VII$_{h}$ space-times is investigated. The general equations for a matter sector consisting of a $p$-form field strength ($p\,\in\,\{1,3\}$), a cosmological constant ($4$-form) and per
Externí odkaz:
http://arxiv.org/abs/1712.08752
Autor:
Thorsrud, Mikjel
Publikováno v:
Class. Quantum Grav. 35 (2018) 095011
We present a complete list of general relativistic shear-free solutions in a class of anisotropic, spatially homogeneous and orthogonal cosmological models containing a collection of $n$ independent $p$-form gauge fields, where $p\in\{0,1,2,3\}$, in
Externí odkaz:
http://arxiv.org/abs/1712.02778
Publikováno v:
JCAP 04 (2014) 010
We study the statistics of the primordial power spectrum in models where massless gauge vectors are coupled to the inflaton, paying special attention to observational implications of having fundamental or effective horizons embedded in a bath of infr
Externí odkaz:
http://arxiv.org/abs/1312.7491
Publikováno v:
Physics Letters B 733C (2014), pp. 140-143
Cosmological local observables are at best statistically determined by the fundamental theory describing inflation. When the scalar inflaton is coupled uniformly to a collection of subdominant massless gauge vectors, rotational invariance is obeyed l
Externí odkaz:
http://arxiv.org/abs/1311.3302
Publikováno v:
JCAP 1310 (2013) 064
We study the Horndeski vector-tensor theory that leads to second order equations of motion and contains a non-minimally coupled abelian gauge vector field. This theory is remarkably simple and consists of only 2 terms for the vector field, namely: th
Externí odkaz:
http://arxiv.org/abs/1308.1867
Autor:
Thorsrud, Mikjel
We study the dynamics of a scalar field with Kaluza-Klein type couplings to cold dark matter and an isotropy-violating vector field. The vector coupling, $f^2(\phi)F^2$, has been studied thoroughly in the context of inflation recently. We generalize
Externí odkaz:
http://arxiv.org/abs/1303.2469
Publikováno v:
JHEP02(2013)146
Horndeski derived a most general vector-tensor theory in which the vector field respects the gauge symmetry and the resulting dynamical equations are of second order. The action contains only one free parameter, $\lambda$, that determines the strengt
Externí odkaz:
http://arxiv.org/abs/1211.5403