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We constrain several models of the early Universe that predict a statistical anisotropy of the cosmic microwave background (CMB) sky. We make use of WMAP9 maps deconvolved with beam asymmetries. As compared to previous releases of WMAP…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-03 Sabir Ramazanov , Grigory Rubtsov

We construct a class of single small field models of inflation that can predict, contrary to popular wisdom, an observable gravitational wave signal in the cosmic microwave background anisotropies. The spectral index, its running, the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Ido Ben-Dayan , Ram Brustein

The possibility to have an infinite open inflationary universe inside a bubble of a finite size is one of the most interesting realizations extensively discussed in the literature. The original idea was based on the theory of tunneling and…

Astrophysics · Physics 2009-09-29 Andrei Linde , Misao Sasaki , Takahiro Tanaka

This thesis is dedicated to studying cosmological inflation, which is a period of accelerated expansion in the very early Universe that is required to explain the observed anisotropies in the cosmic microwave background. Inflation, when…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-02 Chris Pattison

We investigate the effects of non-zero spatial curvature on cosmic inflation in the light of cosmic microwave background (CMB) anisotropy measurements from the Planck 2018 legacy release and from the 2015 observing season of BICEP2 and the…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-12 Lukas T. Hergt , Fruzsina J. Agocs , Will J. Handley , Michael P. Hobson , Anthony N. Lasenby

The recent observation of the cosmic microwave background anisotropy by the WMAP confirmed that the lower multipoles are considerably suppressed. From the standpoint of the cosmic variance, it is nothing but a statistical accident.…

High Energy Physics - Phenomenology · Physics 2009-11-10 Masahiro Kawasaki , Fuminobu Takahashi

The precision reached by the recent CMB measurements gives new insights into the shape of the primordial power spectra of the cosmological perturbations. In the context of inflationary cosmology, this implies that the CMB data are now…

Astrophysics · Physics 2015-10-08 Christophe Ringeval

In this talk we will discuss how inflation can be embedded within a minimal extension of the Standard Model where the inflaton carries the Standard Model charges. There is no need of an ad-hoc scalar field to be introduced in order to…

High Energy Physics - Phenomenology · Physics 2007-09-28 A. Mazumdar

We study temperature and polarization anisotropies of the cosmic microwave background (CMB) radiation sourced from primordial cross-bispectra between metric perturbations and vector fields, which are generated from the inflation model where…

Cosmology and Nongalactic Astrophysics · Physics 2012-12-18 Maresuke Shiraishi , Shohei Saga , Shuichiro Yokoyama

We study the observational implications of a class of inflationary models wherein the inflaton is coupled to the Einstein tensor through a generalized non-minimal derivative coupling (GNMDC). In particular, we explore whether these models…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-03 Yashi Tiwari , Nilanjandev Bhaumik , Rajeev Kumar Jain

This article investigates the predictions of an inflationary phase starting from a homogeneous and anisotropic universe of the Bianchi I type. After discussing the evolution of the background spacetime, focusing on the number of e-folds and…

Astrophysics · Physics 2009-06-23 Cyril Pitrou , Thiago S. Pereira , Jean-Philippe Uzan

We compute the primordial scalar, vector and tensor metric perturbations arising from quantum field inflation. Quantum field inflation takes into account the nonperturbative quantum dynamics of the inflaton consistently coupled to the…

Astrophysics · Physics 2009-11-11 F. J. Cao

We develop a general formalism for analyzing linear perturbations in multiple-field cosmological inflation based on the gauge-ready approach. Our inflationary model consists of an arbitrary number of scalar fields with non-minimal kinetic…

Astrophysics · Physics 2009-11-13 Joydev Lahiri , Gautam Bhattacharya

In light of the recent Planck 2015 results for the measurement of the CMB anisotropy, we study simple inflationary models in the context of the Gauss-Bonnet brane-world cosmology. The brane-world cosmological effect modifies the power…

High Energy Physics - Phenomenology · Physics 2017-03-15 Nobuchika Okada , Satomi Okada

An inflationary scenario is expected to be embedded into an ultraviolet (UV) complete theory such as string theory. The effect of UV complete theories may appear as nontrivial kinetic terms in the low energy effective field theory, which…

High Energy Physics - Theory · Physics 2022-05-18 Chong-Bin Chen , Jiro Soda

We study anisotropic inflation with Gauss-Bonnet correction in presence of a massless vector field. In this scenario, exact anisotropic power-law inflation is realized when the inflaton potential, gauge coupling function and the…

High Energy Physics - Theory · Physics 2016-10-06 Sayantani Lahiri

We present the effective field theory studies of primordial statistical anisotropies in models of anisotropic inflation. The general action in unitary gauge is presented to calculate the leading interactions between the gauge field…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-26 Tahereh Rostami , Asieh Karami , Hassan Firouzjahi

We argue that the lack of power exhibited by cosmic microwave background (CMB) anisotropies at large angular scales might be linked to the onset of inflation. We highlight observational features and theoretical hints that support this view,…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-09 A. Gruppuso , A. Sagnotti

As previously discussed in (D. Sudarsky, Int.J.Mod.Phys.D20:509-552, (2011); [arXiv:0906.0315]), the inflationary account for the emergence of the seeds of cosmic structure falls short of actually explaining the generation of primordial…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Pedro Cañate , Philip Pearle , Daniel Sudarsky

In this thesis we will primarily demonstrate how additional scalar degrees of freedom - which are motivated from many high-energy embeddings - open up new observational windows onto the physics of inflation. We construct a Bayesian…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-11 Robert J. Hardwick