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Gabriel Zsembinszki

Publications and source records attributed to Gabriel Zsembinszki.

9 recordsLinked to original sources
arXiv2007

Imprint of spatial curvature on inflation power spectrum

If the universe had a large curvature before inflation there is a deviation from the scale invariant perturbations of the inflaton at the beginning of inflation. This may have some effect on the CMB anisotropy at large angular scales. We calculate the density perturbations for both open and closed universe cases using the Bunch-Davies vacuum condition on the initial state. We use our power spectrum to calculate the temperature anisotropy spectrum and compare the results with the WMAP three year data. We find that our power spectrum gives a lower quadrupole anisotropy when $Ω-1 >0$, but matches the temperature anisotropy calculated from the standard Ratra-Peebles power spectrum at large $l$. The determination of spatial curvature from temperature anisotropy data is not much affected by the different power spectra which arise from the choice of different boundary conditions for the inflaton perturbation.

astro-ph↗
arXiv2007

Unified Model for Inflation and Dark Matter

We present a model which contains a new complex scalar field $Ψ$, interacting with a new real scalar field, $χ$, and an effective potential whose symmetry is almost exact, being explicitly broken by Planck-scale effects. We study the possibility of relating {\em inflation} with the {\em dark matter} of the universe. We find that for exponentially small explicit breaking, the model accounts for a period of inflation in the early universe and gives a dark matter candidate particle.

astro-ph↗
arXiv2007

Unified Model for Inflation and the Dark Side of the Universe

We present a model with a complex and a real scalar fields and a potential whose symmetry is explicitly broken by Planck-scale physics. For exponentially small breaking, the model accounts for the period of inflation in the early universe and for the period of acceleration of the late universe or for the dark matter, depending on the smallness of the explicit breaking.

astro-ph↗
arXiv2007

Unified model for inflation and dark energy

We present a model based on the idea that Planck-scale effects may produce a small explicit breaking of global symmetries. The model contains a new complex scalar field $Ψ$, charged under a certain global U(1) symmetry, interacting with a new real scalar field $χ$, neutral under U(1). For exponentially small breaking, the model accounts for both {\em early} and {\em late} periods of acceleration of the universe.

astro-ph↗
arXiv2006

Low-scale inflation in a model of dark energy and dark matter

We present a complete particle physics model that explains three major problems of modern cosmology: inflation, dark matter and dark energy, and also gives a mechanism for leptogenesis. The model has a new gauge group $SU(2)_Z$ that grows strong at a scale $Λ\sim 10^{-3}$ eV. We focus on the inflationary aspects of the model. Inflation occurs with a Coleman-Weinberg potential at a low scale, down to $\sim 6\times 10^5\gev$, being compatible with observational data.

astro-ph↗
arXiv2005

Scalar Field Oscillations Contributing to Dark Energy

We use action-angle variables to describe the basic physics of coherent scalar field oscillations in the expanding universe. These analytical mechanics methods have some advantages, like the identification of adiabatic invariants. As an application, we show some instances of potentials leading to equations of state with $p<-ρ/3$, thus contributing to the dark energy that causes the observed acceleration of the universe.

astro-ph↗
arXiv2004

Planck-Scale Effects on Global Symmetries: Cosmology of Pseudo-Goldstone Bosons

We consider a model with a small explicit breaking of a global symmetry, as suggested by gravitational arguments. Our model has one scalar field transforming under a non-anomalous U(1) symmetry, and coupled lo matter and to gauge bosons. The spontaneous breaking of the explicitly broken symmetry gives rise to a massive pseudo-Goldstone boson. We analyze thermal and non-thermal production of this particle in the early universe, and perform a systematic study of astrophysical and cosmological constraints on its properties. We find that for very suppressed explicit breaking the pseudo-Goldstone boson is a cold dark matter candidate.

hep-ph↗
arXiv2002

On Axion Thermalization in the Early Universe

We reanalyze the conditions under which we have a primordial thermal population of axions. Compared with previous studies, we find other processes, involving gluons and quarks, that dominate at high temperatures. We conclude that if the Peccei-Quinn scale fulfills $F_a < 1.2 \times 10^{12} \GeV$ there is thermal axion production. In this case, a period in the early universe exists where axions interact with the QCD plasma and we point out that non-thermal axions produced before the end of this period will thermalize. This could lead to a reduction of the expected density of axions from string decay in models with $F_a < 1.2 \times 10^{12} \GeV$.

hep-ph↗