CMB anisotropies from acausal scaling seeds

We present a new and especially powerful signature of cosmic strings and other topological or nontopological defects in the polarization of the cosmic microwave background (CMB). We show that even if defects contribute 1% or less in the CMB temperature anisotropy spectrum, their signature in the localB-polarization correlation function at angular scales of tens of arc-minutes is much larger than that due to gravitational waves from inflation, even if the latter contribute with a ratio as big as r 0.1 to the temperature anisotropies. We show that when going from non-local to local B-polarization, the ratio of the defect signal-to-noise with respect to the inflationary value increases by about an order of magnitude. Proposed B-polarization experiments, with a good sensitivity on arc-minute scales, may either detect a contribution from topological defects produced after inflation or place stringent limits on them. Already Planck should be able to improve present constraints on defect models by about an order of magnitude, to the level of = Gv 2 < 10 −7 . A future full-sky experiment like CMBpol, with polarization sensitivities of the order of 1µK-arcmin, will be able to constrain the defect parameter to less than a few ×10 −9 , depending on the defect model.

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“…This can only be circumvented if one allows for acausality, i.e. superluminal motion, of the seeds [19], however improbable. In Ref.…”

Section: Resultsmentioning

confidence: 99%

The local B-polarization of the CMB: A very sensitive probe of cosmic defects

et al. 2011

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“…It is surprisingly difficult to create this observed fluctuation spectrum in alternative scenarios that are strictly causal and only act on sub-horizon scales (Spergel and Zaldarriaga 1997 ; Scodeller et al. 2009 ).…”

Section: Part I Dark Energymentioning

confidence: 99%

Cosmology and fundamental physics with the Euclid satellite

Amendola¹,

Appleby²,

Avgoustidis³

et al. 2018

Living Rev Relativ

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964

869

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Euclid is a European Space Agency medium-class mission selected for launch in 2020 within the cosmic vision 2015–2025 program. The main goal of Euclid is to understand the origin of the accelerated expansion of the universe. Euclid will explore the expansion history of the universe and the evolution of cosmic structures by measuring shapes and red-shifts of galaxies as well as the distribution of clusters of galaxies over a large fraction of the sky. Although the main driver for Euclid is the nature of dark energy, Euclid science covers a vast range of topics, from cosmology to galaxy evolution to planetary research. In this review we focus on cosmology and fundamental physics, with a strong emphasis on science beyond the current standard models. We discuss five broad topics: dark energy and modified gravity, dark matter, initial conditions, basic assumptions and questions of methodology in the data analysis. This review has been planned and carried out within Euclid’s Theory Working Group and is meant to provide a guide to the scientific themes that will underlie the activity of the group during the preparation of the Euclid mission.

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“…While there is no conclusive proof that an inflationary phase took place in the early universe, it is surprisingly difficult to create the observed fluctuation spectrum in alternative scenarios that are strictly causal and only act on sub-horizon scales [ 854 , 803 ].…”

Section: Dark Energymentioning

confidence: 99%

Cosmology and Fundamental Physics with the Euclid Satellite

Amendola¹,

Appleby²,

Bacon³

et al. 2013

Living Rev. Relativ.

Self Cite

810

665

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Euclid is a European Space Agency medium-class mission selected for launch in 2019 within the Cosmic Vision 2015–2025 program. The main goal of Euclid is to understand the origin of the accelerated expansion of the universe. Euclid will explore the expansion history of the universe and the evolution of cosmic structures by measuring shapes and red-shifts of galaxies as well as the distribution of clusters of galaxies over a large fraction of the sky.Although the main driver for Euclid is the nature of dark energy, Euclid science covers a vast range of topics, from cosmology to galaxy evolution to planetary research. In this review we focus on cosmology and fundamental physics, with a strong emphasis on science beyond the current standard models. We discuss five broad topics: dark energy and modified gravity, dark matter, initial conditions, basic assumptions and questions of methodology in the data analysis.This review has been planned and carried out within Euclid’s Theory Working Group and is meant to provide a guide to the scientific themes that will underlie the activity of the group during the preparation of the Euclid mission.

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CMB anisotropies from acausal scaling seeds

Cited by 10 publications

References 22 publications

The local B-polarization of the CMB: A very sensitive probe of cosmic defects

The local B-polarization of the CMB: A very sensitive probe of cosmic defects

Cosmology and fundamental physics with the Euclid satellite

Cosmology and Fundamental Physics with the Euclid Satellite

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