Related papers: Dynamical axion misalignment with small instantons
Axion fluctuations generated during inflation lead to isocurvature and non-Gaussian temperature fluctuations in the cosmic microwave background radiation. Following a previous analysis for the model independent string axion we consider the…
In this paper we investigate the vacuum stability of the non-minimally coupled Standard-Model Higgs during a phase of kinetic domination following the end of inflation. The non-minimal coupling to curvature stabilises the Higgs fluctuations…
We consider a model of inflation in which the inflaton field is a rolling axion with a potential which is flat enough to support an intermediate phase of USR inflation. Because of the Chern-Simons interaction, one polarization of the gauge…
We reexamine the recently proposed "little inflation" scenario that allows for a strong first order phase-transition of QCD at non-negligible baryon number in the early universe and its possible observable consequences. The scenario is…
In this work we investigate the quantitative effects of the misalignment kinetic axion on $R^2$ inflation. Due to the fact that the kinetic axion possesses a large kinetic energy which dominates its potential energy, during inflation its…
Multi-natural inflation is studied in the context of warm inflation. We study the warm multi-natural inflation scenario with both linear and cubic temperature-dependent dissipation coefficients. The model is motivated by axion-like…
We propose a new regime of minimal QCD axion dark matter that lies between the pre- and post-inflationary scenarios, such that the Peccei-Quinn (PQ) symmetry is restored only on sufficiently large spatial scales. This leads to a novel…
We discuss quantum gravitational effects in Einstein theory coupled to periodic axion scalars to analyze the viability of several proposals to achieve superplanckian axion periods (aka decay constants) and their possible application to…
Because the inflationary mechanism is extremely sensitive to UV-physics, the construction of theoretically robust models of inflation provides a unique window on Planck-scale physics. We review efforts to use an axion with a shift symmetry…
If the inflaton is a pseudo-scalar axion, the axion shift symmetry can protect the flatness of its potential from too large radiative corrections. This possibility, known as natural inflation, requires an axion scale which is greater than…
We propose a model for cosmic inflation which is based on an effective description of strongly interacting, nonsupersymmetric matter within the framework of dynamical abelian projection and centerization. The underlying gauge symmetry is…
The BICEP2 experiment determined the Hubble parameter during inflation to be about $10^{14}$ GeV. Such high inflation scale is in tension with the QCD axion dark matter if the Peccei-Quinn (PQ) symmetry remains broken during and after…
We investigate the cosmology of an axion that is fundamentally non-compact. During inflation, fluctuations of the effectively massless field populate many QCD vacua, thereby evading conventional isocurvature constraints while generating…
Observable primordial tensor modes in the cosmic microwave background (CMB) would point to a high scale of inflation $H_{I}$. If the scale of Peccei-Quinn (PQ) breaking $f_a$ is greater than $\frac{H_{I}}{2\pi}$, CMB constraints on…
For axions present during inflation, it has been shown that a non-minimal coupling $\xi_\sigma$ of the inflaton to gravity worsens isocurvature bounds, while a non-minimal coupling $\xi_\rho$ of the radial Peccei-Quinn field can alleviate…
The present work suggests that the isocurvature tension between axion and high energy inflationary scenarios may be avoided by considering a double field inflationary model involving the hidden Peccei-Quinn Higgs and the Standard Model one.…
Natural (axionic) inflation can accommodate sizeable primordial tensor modes but suffers from the necessity of trans-Planckian variations of the inflaton field. This problem can be solved via the mechanism of aligned axions…
An extension of the Standard Model with three right-handed neutrinos and a simple invisible axion model can account for all experimentally confirmed signals of new physics (neutrino oscillations, dark matter and baryon asymmetry) in…
In axion gauge field inflation an axion-like particle driving cosmic inflation is coupled to the Chern-Simons density of an Abelian or non-Abelian gauge group. In the case of a non-Abelian gauge group, this can lead to the formation of a…
It is widely believed that string theory easily allows for a QCD axion in the cosmologically favoured mass range. The required small decay constant, $f_a\ll M_P$, can be implemented by using a large compactification volume. This points to…