scholarly journals Gravitational waves induced by scalar perturbations during a gradual transition from an early matter era to the radiation era

2020 ◽  
Vol 1468 ◽  
pp. 012001 ◽  
Author(s):  
Keisuke Inomata ◽  
Kazunori Kohri ◽  
Tomohiro Nakama ◽  
Takahiro Terada
Keyword(s):  
Gravitational Waves ◽  
Gradual Transition ◽  
Scalar Perturbations

On Primordial Black Holes and secondary gravitational waves generated from inflation with solo/multi-bumpy potential

2021 ◽  
Author(s):  
Rui feng Zheng ◽  
Jia ming Shi ◽  
Taotao Qiu
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Waves ◽  
Power Spectra ◽  
Small Scale ◽  
Primordial Black Hole ◽  
Primordial Black Holes ◽  
Slow Roll ◽  
Spherical Collapse ◽  
Scalar Perturbations

Abstract It is well known that primordial black hole (PBH) can be generated in inflation process of the early universe, especially when the inflaton field has some non-trivial features that could break the slow-roll condition. In this paper, we investigate a toy model of inflation with bumpy potential, which has one or several bumps. We found that potential with multi-bump can give rise to power spectra with multi peaks in small-scale region, which can in turn predict the generation of primordial black holes in various mass ranges. We also consider the two possibilities of PBH formation by spherical collapse and elliptical collapse. And discusses the scalar-induced gravitational waves (SIGWs) generated by the second-order scalar perturbations.

scholarly journals SPECTRUM OF GRAVITATIONAL WAVES IN KREIN SPACE QUANTIZATION

2011 ◽  
Vol 26 (36) ◽  
pp. 2697-2702 ◽  
Author(s):  
M. MOHSENZADEH ◽  
A. SOJASI ◽  
E. YUSOFI
Keyword(s):  
Gravitational Waves ◽  
Krein Space ◽  
Slow Roll ◽  
Primordial Power Spectrum ◽  
Alternative Approach ◽  
Special Cases ◽  
Kreĭn Space ◽  
Field Quantization ◽  
Krein Space Quantization ◽  
Scalar Perturbations

The main goal of this paper is to derive the primordial power spectrum for the scalar perturbations generated as a result of quantum fluctuations during an inflationary period by an alternative approach of field quantization.1–3 Formulas are derived for the gravitational waves, special cases of which include power law inflation and inflation in the slow roll approximation, in Krein space quantization.

scholarly journals Gauge Dependence of Gravitational Waves Generated from Scalar Perturbations

2017 ◽  
Vol 842 (1) ◽  
pp. 46 ◽  
Author(s):  
Jai-chan Hwang ◽  
Donghui Jeong ◽  
Hyerim Noh
Keyword(s):  
Gravitational Waves ◽  
Gauge Dependence ◽  
Scalar Perturbations

scholarly journals Odd tensor modes from inflation

2016 ◽  
Vol 31 (21) ◽  
pp. 1640010
Author(s):  
Lorenzo Sorbo
Keyword(s):  
Gravitational Waves ◽  
Gauge Field ◽  
Step Process ◽  
Near Future ◽  
Scalar Perturbations

The existence of a primordial spectrum of gravitational waves is a generic prediction of inflation. Here, I will discuss under what conditions the coupling of a pseudoscalar inflaton to a U(1) gauge field can induce, in a two-step process, gravitational waves with unusual properties such as: (i) a net chirality, (ii) a blue spectrum, (iii) large non-Gaussianities even if the scalar perturbations are approximately Gaussian and (iv) being detectable in the (relatively) near future by ground-based gravitational interferometers.

scholarly journals Gravitational waves and scalar perturbations from spectator fields

2015 ◽  
Vol 2015 (04) ◽  
pp. 011-011 ◽  
Author(s):  
Matteo Biagetti ◽  
Emanuela Dimastrogiovanni ◽  
Matteo Fasiello ◽  
Marco Peloso
Keyword(s):  
Gravitational Waves ◽  
Scalar Perturbations
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