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Most inflationary models predict primordial perturbations to be statistically isotropic and homogeneous. Cosmic microwave background (CMB) observations, however, indicate a possible departure from statistical isotropy in the form of a…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-11 Maresuke Shiraishi , Julian B. Muñoz , Marc Kamionkowski , Alvise Raccanelli

We asses the contribution to the observed large scale anisotropy of the cosmic microwave background radiation, arising from both gravity waves as well as adiabatic density perturbations, generated by a common inflationary mechanism in the…

High Energy Physics - Phenomenology · Physics 2009-10-22 Tarun Souradeep , Varun Sahni

In this paper, inflationary cosmology is reviewed, paying particular attention to its observational signatures associated with large-scale density perturbations generated from quantum fluctuations. In the most general scalar-tensor theories…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-13 Shinji Tsujikawa

We study the asymmetric primordial fluctuations in a model of inflation in which translational invariance is broken by a domain wall. We calculate the corrections to the power spectrum of curvature perturbations; they are anisotropic and…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-02 Sadra Jazayeri , Yashar Akrami , Hassan Firouzjahi , Adam R. Solomon , Yi Wang

There is strong evidence from cosmological data that the universe underwent an epoch of superluminal expansion called inflation. A satisfactory embedding of inflation in fundamental physics has been an outstanding problem at the interface…

High Energy Physics - Phenomenology · Physics 2008-12-26 Rouzbeh Allahverdi

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

Inflationary models within string theory exhibit unusual scalar field dynamics involving non-minimal kinetic terms and generically referred to as k-inflation. In this situation, the standard slow-roll approach used to determine the behavior…

Cosmology and Nongalactic Astrophysics · Physics 2012-05-08 Christophe Ringeval

Recent fits of cosmological parameters by the Wilkinson Microwave Anisotropy Probe (WMAP) measurement favor a primordial scalar spectrum with varying index. This result, if stands, could severely constrain inflation model buildings. Most…

Astrophysics · Physics 2008-11-26 Bo Feng , Mingzhe Li , Ren-Jie Zhang , Xinmin Zhang

We study the QCD--DM scenario by analyzing the imprint of energy injection from decaying dark-sector particles on the spectral distortions (SDs) of the Cosmic Microwave Background (CMB). We adopt a unified framework capable of describing…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-12 Jorge Mastache , Raúl Henriquez-Ortiz

[Abridged] A sharp cut-off in the primordial scalar power spectrum on large scales has been known to improve the fit to the cosmic microwave background (CMB) data when compared to the more standard, nearly scale invariant power spectrum…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-11 H. V. Ragavendra , Debika Chowdhury , L. Sriramkumar

We quantify the limiting factors in optimizing current-technology cosmic microwave background (CMB) polarization experiments in order to learn about inflationary physics. We consider space-based, balloon-borne and ground-based experiments.…

Astrophysics · Physics 2011-05-12 Licia Verde , Hiranya Peiris , Raul Jimenez

We propose the implementation of an imaging telescope in combination with an inter-frequency calibrator to measure the spectral shape of the microwave sky by exploiting the differences in the sky intensity between multiple pairs of…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-25 Suvodip Mukherjee , Joseph Silk , Benjamin D. Wandelt

Cosmological inflation predicts that the scalar spectral index "runs" with scale. Constraints on the values of the spectral runnings, $\alpha_s\equiv \textrm{d} n_s/\textrm{d}\ln k$ and $\beta_s\equiv \textrm{d}\alpha_s/\textrm{d}\ln k$,…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-08 Xiaolei Li , Noah Weaverdyck , Saroj Adhikari , Dragan Huterer , Jessica Muir , Hao-Yi Wu

The simplest inflationary models predict a primordial power spectrum (PPS) of the curvature fluctuations that can be described by a power-law function that is nearly scale-invariant. It has been shown, however, that the low-multipole…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-25 Eleonora Di Valentino , Stefano Gariazzo , Martina Gerbino , Elena Giusarma , Olga Mena

Spectral distortions of the cosmic microwave background (CMB) are sensitive to energy injection by exotic physics in the early universe. The proposed Primordial Inflation Explorer (PIXIE) mission has the raw sensitivity to provide…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-22 Ioana A. Zelko , Douglas P. Finkbeiner

The past, present and future of cosmic microwave background (CMB) anisotropy research is discussed, with emphasis on the Boomerang and Maxima balloon experiments. These data are combined with large scale structure (LSS) information and high…

In this paper, we investigate some consequences of multiple-field inflation for the cosmic microwave background radiation (CMB). We derive expressions for the amplitudes, the spectral indices and the derivatives of the indices of the CMB…

Astrophysics · Physics 2009-11-10 Bartjan van Tent

The primary scientific target of the CMB polarization experiments that are currently being built and proposed is the detection of primordial tensor perturbations. As a byproduct, these instruments will significantly improve constraints on…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-17 Levon Pogosian , Meir Shimon , Matthew Mewes , Brian Keating

We investigate the impact of different choice of prior's range for the reheating epoch on cosmic inflation parameter inference in light of cosmic microwave background (CMB) anisotropy measurements from the {\em Planck} 2018 legacy release…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-30 Mario Ballardini

We build an inflationary model based on Degenerate Higher Order Scalar Tensor (DHOST) theories in a de Sitter background. We determine the scale-dependent power spectrum of curvature perturbations in these theories and we show that such a…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-25 Andrei Lazanu