Cosmic microwave background temperature and polarization anisotropies from the large-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>N</mml:mi></mml:math>limit of global defects

Fenu, Elisa; Figueroa, Daniel G.; Durrer, Ruth; García-Bellido, J.; Kunz, M.

doi:10.1103/physrevd.89.083512

Cited by 11 publications

(41 citation statements)

References 51 publications

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“…(40). In particular, we can check that a radiation eigenvector evolves into a unique matter eigenvector.…”

Section: B Multistage Eigenvector Interpolationmentioning

confidence: 99%

“…Recently some inconsistencies of this approach have been highlighted [40]. First, the signs of a set of eigenvectors are undetermined, and so a rule must be applied to decide on the relative sign when interpolating between a radiation-era eigenvector and a matter-era one.…”

Section: A Simple Eigenvector Interpolationmentioning

confidence: 99%

“…We call our new method fixed-k UETC interpolation. We compare it to previous methods [30,40], finding that it is significantly more accurate.…”

Section: Introductionmentioning

confidence: 99%

“…A second method of generating a set of source functions [40] (see also [33]), which we call multi-stage eigenvector interpolation, improves on simple eigenvector interpolation by generating a set of linear combinations of the pure radiation and pure matter UETCs, whose eigenvectors can be more easily matched. We write the "transition" UETCs as…”

Section: B Multistage Eigenvector Interpolationmentioning

confidence: 99%

“…We then divide up the radiation-matter transition era into N U þ 1 intervals with a set of N U times τ i , and define a monotonically decreasing interpolating function fðτÞ, which will define the linear combination in (40) according to…”

Section: B Multistage Eigenvector Interpolationmentioning

confidence: 99%

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Energy-momentum correlations for Abelian Higgs cosmic strings

et al. 2016

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We report on the energy-momentum correlators obtained with recent numerical simulations of the Abelian Higgs model, essential for the computation of cosmic microwave background and matter perturbations of cosmic strings. Due to significant improvements both in raw computing power and in our parallel simulation framework, the dynamical range of the simulations has increased fourfold both in space and time, and for the first time we are able to simulate strings with a constant physical width in both the radiation and matter eras. The new simulations improve the accuracy of the measurements of the correlation functions at the horizon scale and confirm the shape around the peak. The normalization is slightly higher in the high wave-number tails, due to a small increase in the string density. We study, for the first time, the behavior of the correlators across cosmological transitions and discover that the correlation functions evolve adiabatically; i.e., the network adapts quickly to changes in the expansion rate. We propose a new method for constructing source functions for Einstein-Boltzmann integrators, comparing it with two other methods previously used. The new method is more consistent, easier to implement, and significantly more accurate.

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“…(40). In particular, we can check that a radiation eigenvector evolves into a unique matter eigenvector.…”

Section: B Multistage Eigenvector Interpolationmentioning

confidence: 99%

Section: A Simple Eigenvector Interpolationmentioning

confidence: 99%

“…We call our new method fixed-k UETC interpolation. We compare it to previous methods [30,40], finding that it is significantly more accurate.…”

Section: Introductionmentioning

confidence: 99%

Section: B Multistage Eigenvector Interpolationmentioning

confidence: 99%

Section: B Multistage Eigenvector Interpolationmentioning

confidence: 99%

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Energy-momentum correlations for Abelian Higgs cosmic strings

et al. 2016

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Can self-ordering scalar fields explain the BICEP2 B-mode signal?

Durrer

Figueroa

Kunz

2014

J. Cosmol. Astropart. Phys.

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Abstract:We show that self-ordering scalar fields (SOSF), i.e. non-topological cosmic defects arising after a global phase transition, cannot explain the B-mode signal recently announced by BICEP2. We compute the full C B angular power spectrum of B-modes due to the vector and tensor perturbations of SOSF, modeled in the large-N limit of a spontaneous broken global O(N ) symmetry. We conclude that the low-multipoles detected by BICEP2 cannot be due mainly to SOSF, since they have the wrong spectrum at low multipoles. As a byproduct we derive the first cosmological constraints on this model, showing that the BICEP2 B-mode polarization data admits at most a 2-3% contribution from SOSF in the temperature anisotropies, similar to (but somewhat tighter than) the recently studied case of cosmic strings.

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Primordial magnetic fields from self-ordering scalar fields

Horiguchi¹,

Ichiki²,

Sekiguchi³

et al. 2015

J. Cosmol. Astropart. Phys.

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Abstract. A symmetry-breaking phase transition in the early universe could have led to the formation of cosmic defects. Because these defects dynamically excite not only scalar and tensor type cosmological perturbations but also vector type ones, they may serve as a source of primordial magnetic fields. In this study, we calculate the time evolution and the spectrum of magnetic fields that are generated by a type of cosmic defects, called global textures, using the non-linear sigma (NLSM) model. Based on the standard cosmological perturbation theory, we show, both analytically and numerically, that a vector-mode relative velocity between photon and baryon fluids is induced by textures, which inevitably leads to the generation of magnetic fields over a wide range of scales. We find that the amplitude of the magnetic fields is given by B ∼ 10 −9 ((1 + z)/10 3 ) −2.5 (v/m pl ) 2 k/Mpc −1 3.5

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Cosmic microwave background temperature and polarization anisotropies from the large-Nlimit of global defects

Cited by 11 publications

References 51 publications

Energy-momentum correlations for Abelian Higgs cosmic strings

Energy-momentum correlations for Abelian Higgs cosmic strings

Can self-ordering scalar fields explain the BICEP2 B-mode signal?

Primordial magnetic fields from self-ordering scalar fields

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