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CMB anisotropies are modified by the weak lensing effect of intervening large scale structures on the photon path from the last scattering surface to the observer. This has to be accounted for when observational data of sensitive…

Astrophysics · Physics 2010-10-27 Jonathan Rocher , Karim Benabed , Francois Bouchet

We study the emergence of anisotropic (Bianchi IX) inflationary universes with no-boundary conditions in the path integral approach to quantum gravity. In contrast to previous work, we find no evidence for any limit to how large the…

High Energy Physics - Theory · Physics 2017-04-19 Sebastian F. Bramberger , Shane Farnsworth , Jean-Luc Lehners

For icosahedral inflation, we compute the tensor modes' two-point function in the presence of higher derivative corrections, and show that in general this features anisotropies that are aligned with the underlying icosahedral structure. The…

High Energy Physics - Theory · Physics 2018-07-12 Jonghee Kang , Alberto Nicolis

We study single field inflation in noncommutative spacetime and compute two-point and three-point correlation functions for the curvature perturbation. We find that both power spectrum and bispectrum for comoving curvature perturbation are…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-20 Akhilesh Nautiyal

A recent study of the rotation of the plane of polarization of light from 160 cosmological sources claims to find significant evidence for cosmological anisotropy. We point out methodological weaknesses of that study, and reanalyze the same…

Astrophysics · Physics 2009-12-30 Thomas J. Loredo , Eanna E. Flanagan , Ira M. Wasserman

We study statistical anisotropies generated in the observed two-point function of the cosmic microwave background (CMB) fluctuations if the primordial statistics are non-Gaussian. Focusing on the dipole modulations of the anisotropies, we…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-17 Saroj Adhikari , Anne-Sylvie Deutsch , Sarah Shandera

We examine the behavior of an anisotropic brane-world in the presence of inflationary scalar fields. We show that, contrary to naive expectations, a large anisotropy does not adversely affect inflation. On the contrary, a large initial…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Roy Maartens , Varun Sahni , Tarun Deep Saini

The observed distribution of galaxies has local transverse isotropy around the line-of- sight (LOS) with respect to the observer. The difference in the statistical clustering signal along and across the line-of-sight encodes important…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-13 Lado Samushia , Enzo Branchini , Will Percival

A brief account is given of large-scale structure modelling based on the assumption that the initial perturbations arise from inflation. A recap is made of the implications of inflation for large-scale structure; under the widely applicable…

Astrophysics · Physics 2007-05-23 Andrew R Liddle

The influence of Inflation on initial (i.e. at Planck's epoch) large anisotropy of the Universe is studied, considering a more general metric than the isotropic one: the locally rotationally symmetric (L.R.S.) Bianchi IX metric. We find,…

General Relativity and Quantum Cosmology · Physics 2014-11-17 R. Bergamini , P. Sedici , P. Verrocchio

In this paper, we present the higher order spectra of a scalar field produced through the higher derivative interactions in the initially anisotropic universe. Although we ignore the backreaction of the scalar field on the geometry, our…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Masato Minamitsuji

We examine all-sky cosmic microwave background (CMB) temperature maps on large angular scales to compare their consistency with two scenarios: the standard inflationary quantum picture, and a distribution constrained to have a universal…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-13 Nathaniel Selub , Frederick Wehlen , Craig Hogan , Stephan S. Meyer

The shift-symmetric coupling of a pseudo-scalar particle driving inflation to gauge fields provides a unique way of probing cosmic inflation. We show for an SU(2) gauge group how a classical isotropic background gauge field develops from…

High Energy Physics - Phenomenology · Physics 2019-04-24 Valerie Domcke , Ben Mares , Francesco Muia , Mauro Pieroni

Bayesian model comparison penalizes models with more free parameters that are allowed to vary over a wide range, and thus offers the most robust method to decide whether some given data require new parameters. In this paper, we ask a simple…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-28 Tommaso Giannantonio , Eiichiro Komatsu

The Taylor expansion method has been used to investigate the scale dependence of the power spectrum of the curvature perturbation. In the present study, an alternative numerical method is used to clarify the $k$ dependence. Although there…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-06 Shiro Hirai , Tomoyuki Takami

We study an anisotropic inflation model with a gauge kinetic function for a non-abelian gauge field. We find that, in contrast to abelian models, the anisotropy can be either a prolate or an oblate type, which could lead to a different…

High Energy Physics - Theory · Physics 2015-05-27 Keiju Murata , Jiro Soda

We study the intermediate tachyon inflation in an anisotropic background. By using the Friedmann equations obtained in the anisotropic geometry, we obtain the slow-roll parameters in the tachyon model. The presence of the anisotropic…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-05 Narges Rashidi

The primordial bispectrum has been considered in the past decade as a powerful probe of the physical processes taking place in the early Universe. Within the inflationary paradigm, the properties of the bispectrum are one of the keys that…

General Relativity and Quantum Cosmology · Physics 2015-03-09 Gabriel Leon , Daniel Sudarsky

We study constraints on primordial mode-coupling from the power spectrum, squeezed-limit bispectrum and collapsed trispectrum of matter and halos. We describe these statistics in terms of long-wavelength $2$-point functions involving the…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-20 Roland de Putter

We revisit the dynamics of the axial coupling between many N-flatons and an Abelian gauge field, with special attention to its statistically anisotropic signal. The anisotropic power spectrum of curvature perturbations associated to the…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-02 Federico R. Urban