CMB spectral μ-distortion of multiple inflation scenario

Bae, Gimin; Bae, Sungjae; Choe, Seungho; Lee, Seo Hyun; Lim, Jung‐won; Zoe, Heeseung

doi:10.1016/j.physletb.2018.05.015

“…Refs. [207,208,209,210,211,212,213,214,215,216,217,218,219,220,221]. Typically in scenarios where the secondary stage of inflation starts due to a spectator field σ acquiring a vev during the first stage of inflation, the vev has to be very large for the field to become energetically dominant while still in slow-roll to trigger a new period of inflation: for example, for a quadratic spectator potential V σ ∝ σ 2 the criterion is |σ| M P / √ 4π.…”

Section: Multistep Inflationmentioning

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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“…Hence, the changes in the transfer functions according to the value of υ could be explored by smallscale observations including CMB spectral distortions [24], the substructure of galaxies [25,27,28], and the 21 cm hydrogen line [25,29]. Our results can be applied to the calculation for the density perturbations in multiple inflation scenarios [28,30,31].…”

Section: Discussionmentioning

confidence: 89%

“…For υ ≫ 1, we return to the case of thermal inflation plus radiation, and equations ( 9) and ( 10) reduce to equation (20) giving equation (30) as the proper solution.…”

Section: Large Scales κ ≪mentioning

confidence: 99%

Modeling cosmological perturbations of thermal inflation

Bae,

Hong,

Zoe

2023

Class. Quantum Grav.

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We consider a simple system consisting of matter, radiation and vacuum components to model the impact of thermal inflation on the evolution of primordial perturbations. The vacuum energy magnifies the primordial modes entering the horizon before its domination, making them potentially observable, and the resulting transfer function reflects the phase changes and energy contents. To determine the transfer function, we follow the curvature perturbation from well outside the horizon during radiation domination to well outside the horizon during vacuum domination and evaluate it on a constant radiation density hypersurface, as is appropriate for the case of thermal inflation. The shape of the transfer function is determined by the ratio of vacuum energy to radiation at matter-radiation equality, which we denote by υ , and has two characteristic scales, k a and k b , corresponding to the horizon sizes at matter radiation equality and the beginning of the inflation, respectively. If υ ≪ 1 , the Universe experiences radiation, matter and vacuum domination eras and the transfer function is flat for k ≪ k b , oscillates with amplitude 1 / 5 for k b ≪ k ≪ k a and oscillates with amplitude 1 for k ≫ k a . For υ ≫ 1 , the matter domination era disappears, and the transfer function reduces to being flat for k ≪ k b and oscillating with amplitude 1 for k ≫ k b .

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“…Refs. [198][199][200][201][202][203][204][205][206][207][208][209][210][211][212]. Typically in scenarios where the secondary stage of inflation starts due to a spectator field σ acquiring a vev during the first stage of inflation, the vev has to be very large for the field to become energetically dominant while still in slow-roll to trigger a new period of inflation: for example, for a quadratic spectator potential V σ ∝ σ 2 the criterion is |σ| M P / √ 4π.…”

Section: Multistep Inflationmentioning

confidence: 99%

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

Allahverdi,

Amin,

Berlin

et al. 2020

Preprint

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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.

show abstract

CMB spectral μ-distortion of multiple inflation scenario

Cited by 8 publications

References 98 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

Modeling cosmological perturbations of thermal inflation

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

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