Curvaton scenarios with inflaton decays into curvatons

Byrnes, Christian T.; Cortês, Marina; Liddle, Andrew R.

doi:10.1103/physrevd.94.063525

“…In the simplest case, the curvaton is assumed to have a quadratic potential and negligible couplings to the inflaton field (any couplings could allow the inflaton to decay into the curvaton, which can have a big phenomenological impact given the initial subdominance of the curvaton [554,534,555,556]). In this case, analytic results exist for the spectral index of the curvaton perturbations and the local non-Gaussianity in terms of r decay…”

Section: Curvaton Perturbations and Local Non-gaussianitymentioning

confidence: 99%

The First Three Seconds: a Review of Possible Expansion Histories of the Early Universe

Allahverdi¹,

Amin²,

Berlin³

et al. 2021

TheOJA

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It is commonly assumed that the energy density of the Universe was dominated by radiation between reheating after inflation and the onset of matter domination 54,000 years later. While the abundance of light elements indicates that the Universe was radiation dominated during Big Bang Nucleosynthesis (BBN), there is scant evidence that the Universe was radiation dominated prior to BBN. It is therefore possible that the cosmological history was more complicated, with deviations from the standard radiation domination during the earliest epochs. Indeed, several interesting proposals regarding various topics such as the generation of dark matter, matter-antimatter asymmetry, gravitational waves, primordial black holes, or microhalos during a nonstandard expansion phase have been recently made. In this paper, we review various possible causes and consequences of deviations from radiation domination in the early Universe -taking place either before or after BBN -and the constraints on them, as they have been discussed in the literature during the recent years.

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“…One line of investigation is to revisit the simple inflationary models (see e.g. [3]). Here we tackle another question -are there alternative explanations of the signal?…”

Section: Introductionmentioning

confidence: 99%

Can Primordial Magnetic Fields be the Origin of the BICEP2 Data?

Bonvin

¹

,

Durrer

²

,

Maartens

³

2014

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If the B-mode signal in the cosmic microwave background polarization seen by the BICEP2 experiment is confirmed, it has dramatic implications for models of inflation. The result is also in tension with Planck limits on standard inflationary models. It is, therefore, important to investigate whether this signal can arise from alternative sources. If so, this could lessen the pressure on inflationary models and the tension with Planck data. We investigate whether vector and tensor modes from primordial magnetic fields can explain the signal. We find that, in principle, magnetic fields generated during inflation can indeed produce the required B mode, for a suitable range of energy scales of inflation. In this case, the primordial gravitational wave amplitude is negligible, so that there is no tension with Planck and no problems posed for current inflationary models. However, the simplest magnetic model is in tension with Planck limits on non-Gaussianity in the trispectrum. It may be possible to fine tune the magnetogenesis model so that this non-Gaussianity is suppressed. Alternatively, a weaker magnetic field can pass the non-Gaussianity constraints and allow the primordial tensor mode to be reduced to r ≃ 0.09, thus removing the tension with Planck data and alleviating the problems with simple inflationary models.

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“…In the simplest case, the curvaton is assumed to have a quadratic potential and negligible couplings to the inflaton field (any couplings could allow the inflaton to decay into the curvaton, which can have a big phenomenological impact given the initial subdominance of the curvaton [506,[526][527][528]). In this case, analytic results exist for the spectral index of the curvaton perturbations and the local non-Gaussianity in terms of r decay :…”

Section: Curvaton Perturbations and Local Non-gaussianitymentioning

confidence: 99%

The First Three Seconds: a Review of Possible Expansion Histories of the Early Universe

Allahverdi,

Amin,

Berlin

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

It is commonly assumed that the energy density of the Universe was dominated by radiation between reheating after inflation and the onset of matter domination 54,000 years later. While the abundance of light elements indicates that the Universe was radiation dominated during Big Bang Nucleosynthesis (BBN), there is scant evidence that the Universe was radiation dominated prior to BBN. It is therefore possible that the cosmological history was more complicated, with deviations from the standard radiation domination during the earliest epochs. Indeed, several interesting proposals regarding various topics such as the generation of dark matter, matter-antimatter asymmetry, gravitational waves, primordial black holes, or microhalos during a nonstandard expansion phase have been recently made. In this paper, we review various possible causes and consequences of deviations from radiation domination in the early Universe -taking place either before or after BBN -and the constraints on them, as they have been discussed in the literature during the recent years.

show abstract

Curvaton scenarios with inflaton decays into curvatons

Cited by 7 publications

References 44 publications

The First Three Seconds: a Review of Possible Expansion Histories of the Early Universe

The First Three Seconds: a Review of Possible Expansion Histories of the Early Universe

Can Primordial Magnetic Fields be the Origin of the BICEP2 Data?

The First Three Seconds: a Review of Possible Expansion Histories of the Early Universe

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