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Particle production in de Sitter spacetime arises from the exponential expansion of space, rendering the Bunch-Davies vacuum perceived as a particle-containing state by late-time observers. For states defined as eigenstates of both momentum…

High Energy Physics - Theory · Physics 2025-03-14 Nicolás Parra , Spyros Sypsas , Gonzalo A. Palma , Cristóbal Zenteno

Entangled inflationary quantum states offer an interesting alternative to the standard Bunch-Davies vacuum. While they can be viewed from the point of view of a theory of effective initial states, it has been unclear exactly how such states…

High Energy Physics - Theory · Physics 2019-02-05 R. Holman , Benoit J. Richard

Why is non-Gaussianity interesting? One of generic predictions from inflationary scenarios is that primordial fluctuations are exactly Gaussian in linear order; however, the non-linearity in the inflation will produce weak non-Gaussianity.…

Astrophysics · Physics 2017-08-23 Eiichiro Komatsu , David N. Spergel

We investigate the role of bulk viscous pressure on the warm inflationary modified Chaplygin gas in brane-world framework in the presence of standard scalar field. We assume the intermediate inflationary scenario in strong dissipative…

General Relativity and Quantum Cosmology · Physics 2017-02-22 Abdul Jawad , Amara Ilyas , Shamaila Rani

In this work, we present a method for implementing the $\delta N$ formalism to study the primordial non-Gaussianity produced in multiple three-form field inflation. Using a dual description relating three-form fields to noncanonical scalar…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-09 K. Sravan Kumar , David J. Mulryne , Nelson J. Nunes , João Marto , Paulo Vargas Moniz

In this paper we provide a consistency relation between the amplitude of the hemispherical bipolar asymmetry, $A$, and the amplitude of the primordial non-Gaussianity in the squeezed limit, $f_{NL}$, as $|A| \lesssim 10^{-1} f_{NL}$. We…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-30 Mohammad Hossein Namjoo , Shant Baghram , Hassan Firouzjahi

We study the impact of (generalized) cuscuton models on standard single scalar field inflation. Generalized cuscuton models are characterized by spatial covariant gravity where a scalar degree of freedom is made non dynamical, and there are…

General Relativity and Quantum Cosmology · Physics 2022-05-10 Nicola Bartolo , Alexander Ganz , Sabino Matarrese

The effect of the initial conditions in inflation on scalar and tensor perturbations is investigated. Formulae for the power spectra of gravitational waves and curvature perturbations for any initial conditions in inflation are derived, and…

High Energy Physics - Theory · Physics 2007-05-23 Shiro Hirai

In this paper, we discuss the non-Guassianity originated from the $\alpha$-vacuum on the CMB anisotropy. For $\alpha$-vacuum, there exist correlation between points in the acausal two patches of de Sitter spactime. Such kind of correlation…

High Energy Physics - Theory · Physics 2009-09-02 Wei Xue , Bin Chen

Effect of non-canonical scalar fields on the CMB imprints of the anisotropic inflation will be discussed in details in this paper. In particular, we are able to obtain the general formalism of the angular power spectra in the scalar…

General Relativity and Quantum Cosmology · Physics 2021-05-07 Tuan Q. Do , W. F. Kao , Ing-Chen Lin

We study the primordial non-Gaussinity predicted from simple models of inflation with a linear potential and superimposed oscillations. This generic form of the potential is predicted by the axion monodromy inflation model, that has…

High Energy Physics - Phenomenology · Physics 2014-11-20 Steen Hannestad , Troels Haugboelle , Philip R. Jarnhus , Martin S. Sloth

We describe a general scenario where primordial non-Gaussian curvature perturbations are generated in models with extra scalar fields. The extra scalars communicate to the inflaton sector mainly through the tachyonic (waterfall) field…

High Energy Physics - Theory · Physics 2008-11-26 Bhaskar Dutta , Jason Kumar , Louis Leblond

We study squeezed limit $f_{NL}$ generation by excited initial inflationary states in a model independent way. We restrict "excited" to mean a Bogoliubov transformation of the Bunch Davies state. We simultaneously impose the constraints…

High Energy Physics - Theory · Physics 2014-06-02 Aditya Aravind , Dustin Lorshbough , Sonia Paban

The possibility of the resilience of the beginning of inflation under unfavorable conditions is examined by considering the initial state of the inflaton field to be in the form of a relativistic gas with some of its properties in close…

High Energy Physics - Theory · Physics 2023-04-05 Lasha Berezhiani , Mark Trodden

Models of cosmic inflation suggest that our universe underwent an early phase of accelerated expansion, driven by the dynamics of one or more scalar fields. Inflationary models make specific, quantitative predictions for several observable…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-10 David I. Kaiser

We study the statistics of the primordial power spectrum in models where massless gauge vectors are coupled to the inflaton, paying special attention to observational implications of having fundamental or effective horizons embedded in a…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-07 Mikjel Thorsrud , Federico R. Urban , David F. Mota

We study the non-Gaussian features in single-field slow-roll inflationary scenario where inflation is preceded by a radiation era. In such a scenario both bispectrum and trispectrum non-Gaussianities are enhanced. Interestingly, the…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-11 Suratna Das

The methods of effective field theory are used to study generic theories of inflation with a single inflaton field and to perform a general analysis of the associated non-Gaussianities. We investigate the amplitudes and shapes of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Nicola Bartolo , Matteo Fasiello , Sabino Matarrese , Antonio Riotto

Given the latest observational constraints coming from the joint analyses of the Atacama Cosmology Telescope, the Planck Satellite and other missions, we point out the possibility of reconciling fundamental particle-physics models of…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-04 Suddhasattwa Brahma , Jaime Calderón-Figueroa

We present a review of vector field models of inflation and, in particular, of the statistical anisotropy and non-Gaussianity predictions of models with SU(2) vector multiplets. Non-Abelian gauge groups introduce a richer amount of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Emanuela Dimastrogiovanni , Nicola Bartolo , Sabino Matarrese , Antonio Riotto