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Bouncing models of cosmology, as they arise e.g. in loop quantum cosmology, can be followed by an inflationary phase and generate close-to-scale-invariant fluctuation spectra as observed in the Cosmic Microwave Background (CMB). However,…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-12 Bartjan van Tent , Paola C. M. Delgado , Ruth Durrer

We investigate whether non-adiabatic perturbations from inflation could produce an asymmetric distribution of temperature anisotropies on large angular scales in the cosmic microwave background (CMB). We use a generalised non-linear $\delta…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Hooshyar Assadullahi , Hassan Firouzjahi , Mohammad Hossein Namjoo , David Wands

We consider a dynamical model for dark energy based on an ultralight mass scalar field with very large-scale inhomogeneities. This model may cause observable impacts on the anisotropic properties of the cosmic microwave background (CMB)…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-11 Yue Nan , Kazuhiro Yamamoto

We investigate the hemispherical power asymmetry observed in the CMBR by attributing it to an early inhomogeneous phase of cosmic expansion. Unlike the conventional assumption of a perfectly isotropic and homogeneous pre-inflationary…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-30 Akash Gandhi , Mohit Panwar , Pankaj Jain

First, we establish which measures of large-scale perturbations are least afflicted by gauge artifacts and directly map the apparent evolution of inhomogeneities to local interactions of cosmological species. Considering nonlinear and…

Astrophysics · Physics 2007-05-23 Sergei Bashinsky

The observed power spectrum of the cosmic microwave background (CMB) is consistent with inflationary cosmology, which predicts a nearly scale-invariant power spectrum of quantum fluctuations of the inflaton field as they exit the Hubble…

High Energy Physics - Theory · Physics 2007-05-23 Leonard Parker

Collisions between cosmic bubbles of different vacua are a generic feature of false vacuum eternal inflation scenarios. While previous studies have focused on the consequences of a single collision event in an observer's past, we begin here…

High Energy Physics - Theory · Physics 2013-05-30 Jonathan Kozaczuk , Anthony Aguirre

Usually, we assume that there is no inhomogeneity isotropic in terms of our location in our uni- verse. This assumption has not been observationally confirmed yet in sufficient accuracy, and we need to consider the possibility that there…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-06 Hiroyuki Negishi , Ken-ichi Nakao

We analyze the spectrum of cosmic microwave background (CMB) anisotropies in the timescape cosmology: a potentially viable alternative to homogeneous isotropic cosmologies without dark energy. We exploit the fact that the timescape…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 M. Ahsan Nazer , David L. Wiltshire

We analyse the CMB radiation in spherical 3-spaces with non-trivial topology. The focus is put on an inhomogeneous space which possesses observer dependent CMB properties. The suppression of the CMB anisotropies on large angular scales is…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 R. Aurich , P. Kramer , S. Lustig

The frequency spectrum of the cosmic microwave background (CMB) is a relatively untapped source of data which can allow us to peer beyond the surface of last scattering. Small deviations away from a perfect blackbody shape will encode…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-21 Bryce Cyr

Noncommutative geometry can provide effective description of physics at very short distances taking into account generic effects of quantum gravity. Inflation amplifies tiny quantum fluctuations in the early universe to macroscopic scales…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-18 Tomi S. Koivisto , David F. Mota

We analyze the apparent horizon dynamics in the inhomogeneous Clifton-Mota-Barrow solution of Brans-Dicke theory. This solution models a central matter configuration embedded in a cosmological background. In certain regions of the parameter…

General Relativity and Quantum Cosmology · Physics 2013-03-01 Vincenzo Vitagliano , Valerio Faraoni , Thomas P. Sotiriou , Stefano Liberati

CMB foregrounds consist of all radiation between the surface of last scattering and the detectors, which can interfere with the cosmological interpretation of CMB data. Fortunately, in temperature (intensity), even though the foregrounds…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-14 Clive Dickinson

A particularly attractive feature of inflation is that quantum fluctuations in the inflaton field may have seeded inhomogeneities in the cosmic microwave background (CMB) and the formation of large-scale structure. In this paper, we…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-21 Fulvio Melia

In this article we discuss the role of current and future CMB measurements in pinning down the model of inflation responsible for the generation of primordial curvature perturbations. By considering a parameterization of the effective field…

High Energy Physics - Theory · Physics 2014-10-03 Rhiannon Gwyn , Gonzalo A. Palma , Mairi Sakellariadou , Spyros Sypsas

Recent results from cosmic microwave background (CMB) experiments verify several of the predictions of inflation, while ruling out a number of alternative structure-formation scenarios. Given the successes of the theory, the obvious next…

Astrophysics · Physics 2007-05-23 Marc Kamionkowski

In our previous paper \cite{8}, we proposed a cosmological model from the emergence of space, which possesses a significant character of evaluating the vacuum energy from the Hubble constant and the age of universe. And one problem of this…

General Relativity and Quantum Cosmology · Physics 2016-01-01 Zi-Liang Wang , Jian-Bo Deng

With WMAP putting the phenomenological standard model of cosmology on a strong footing, one can look forward to mining the cosmic microwave background (CMB) for fundamental physics with higher sensitivity and on smaller scales. Future CMB…

Astrophysics · Physics 2015-06-24 Manoj Kaplinghat

We explore the possible cosmological consequence of the gravitational coupling between the inflaton and axion-like fields. In view of the forthcoming cosmic microwave background (CMB) polarization and lensing data, we study the sensitivity…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-12 Kenji Kadota , Jinn-Ouk Gong , Kiyotomo Ichiki , Takahiko Matsubara
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