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We revisit the scenario where inflation is preceded by a radiation era by considering that the inflaton too could have been in thermal equilibrium early in the radiation era. Hence we take into account not only the effect of a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Suratna Das , Gaurav Goswami , Jayanti Prasad , Raghavan Rangarajan

We examine the effects of dark energy dynamics and spatial curvature on cosmic reionization by studying reionization in tilted spatially-flat and untilted non-flat XCDM and $\phi$CDM dynamical dark energy inflation models that best fit the…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-19 Sourav Mitra , Chan-Gyung Park , Tirthankar Roy Choudhury , Bharat Ratra

The simple assumption of an instantaneous reionization of the Universe may bias estimates of cosmological parameters. In this paper a model-independent principal component method for the reionization history is applied to give constraints…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-21 Wei-Ming Dai , Zong-Kuan Guo , Rong-Gen Cai

A period of inflation in the early universe produces a nearly scale-invariant spectrum of gravitational waves over a huge range in wavelength. If the amplitude of this gravitational wave background is large enough to be detectable with…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Jerod Caligiuri , Arthur Kosowsky , William H. Kinney , Naoki Seto

We investigate density perturbations generated through modulated reheating while inflation is driven by a conformally coupled scalar field. A large running of the spectral index is obtained, which reflects the basic nature of conformal…

High Energy Physics - Theory · Physics 2009-05-13 Takeshi Kobayashi , Shinji Mukohyama

In the ``natural inflation'' model, the inflaton potential is periodic. We show that Planck scale physics may induce corrections to the inflaton potential, which is also periodic with a greater frequency. Such high frequency corrections…

Astrophysics · Physics 2008-11-26 Xiulian Wang , Bo Feng , Mingzhe Li , Xue-Lei Chen , Xinmin Zhang

We revisit the inflection point inflation with an extended discussion to large field values and consider the reheating effects on the inflationary predictions. Parametrizing the reheating dynamics in terms of the reheating temperature and…

High Energy Physics - Phenomenology · Physics 2016-06-22 Soo-Min Choi , Hyun Min Lee

We revisit large field inflation models with modulations in light of the recent discovery of the primordial B-mode polarization by the BICEP2 experiment, which, when combined with the Planck + WP + highL data, gives a strong hint for…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-27 Michael Czerny , Takeshi Kobayashi , Fuminobu Takahashi

We confront the warm inflation observational predictions directly with the latest CMB data. We focus on a linear temperature (T) dissipative coefficient combined with the simplest model of inflation, a quartic chaotic potential. Although…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-06 Mar Bastero-Gil , Sukannya Bhattacharya , Koushik Dutta , Mayukh Raj Gangopadhyay

The recent low value of Planck (2016) integrated optical depth to Thomson scattering suggests that the reionization occurred fairly suddenly, disfavoring extended reionization scenarios. This will have a significant impact on the 21cm power…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-27 Sultan Hassan , Romeel Dave , Kristian Finlator , Mario G. Santos

Warm inflation is commonly studied under the assumption that the stochastic force sourcing inflaton fluctuations is Markovian. Realistic thermal systems, however, possess finite relaxation times and can therefore generate colored noise with…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-13 Mayukh R. Gangopadhyay , Nilanjana Kumar

In the present work we study the consequences of considering a new family of single-field inflation models, called power-law plateau inflation, in the warm inflation framework. We consider the inflationary expansion is driven by a standard…

General Relativity and Quantum Cosmology · Physics 2017-05-24 Abdul Jawad , Nelson Videla , Faiza Gulshan

We consider trapped inflation in a higher dimensional field space: particle production at a dense distribution of extra species points leads to a terminal velocity at which inflation can be driven in steep potentials. We compute an…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-02 Diana Battefeld , Thorsten Battefeld , Daniel Fiene

The effect of the initial condition of inflation on the power spectra of scalar and tensor perturbations is estimated assuming a slow-roll inflation model. By defining a more general initial state in inflation particular properties of the…

Astrophysics · Physics 2007-10-15 Shiro Hirai , Tomoyuki Takami

The recent Planck results and future releases on the horizon present a key opportunity to address a fundamental question in inflationary cosmology of whether primordial density perturbations have a quantum or thermal origin, i.e. whether…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-20 Sam Bartrum , Arjun Berera , Joao G. Rosa

We study power law inflation (PLI) with a monomial potential and find a novel exact solution. It is well known that conventional PLI with exponential potential is inconsistent with the Planck data. Unlike the standard PLI, present model…

General Relativity and Quantum Cosmology · Physics 2023-01-02 Prasenjit Paul , Rikpratik Sengupta , Saibal Ray

We adopt methods from statistical field theory to stochastic inflation. For the example of a free test field in de Sitter and power-law inflation, the power spectrum of long-wavelength fluctuations is computed. We study its dependence on…

General Relativity and Quantum Cosmology · Physics 2011-02-01 Florian Kuhnel , Dominik J. Schwarz

The effect of the length of inflation on the power spectra of scalar and tensor perturbations is estimated using the power-law inflation model with a scale factor of a(t) = t^q. Considering various pre-inflation models with…

Astrophysics · Physics 2015-06-24 Shiro Hirai , Tomoyuki Takami

We point out that polarization measurements as planned for the upcoming PLANCK mission can significantly enhance the accuracy of cosmic parameter estimation compared to the temperature anisotropy spectrum alone. In order to illustrate this,…

Astrophysics · Physics 2007-05-23 Pavel Naselsky , Jens Schmalzing , Jesper Sommer-Larsen , Steen Hannested

We revisit the renormalizable polynomial inflection point model of inflation, focusing on the small field scenario which can be treated fully analytically. In particular, the running of the spectral index is predicted to be $\alpha = -1.43…

High Energy Physics - Phenomenology · Physics 2021-09-22 Manuel Drees , Yong Xu