Primordial magnetic fields from self-ordering scalar fields

Horiguchi, Kouichirou; Ichiki, Kiyotomo; Sekiguchi, Toyokazu; Sugiyama, Naoshi

doi:10.1088/1475-7516/2015/04/007

Cited by 10 publications

(18 citation statements)

References 40 publications

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“…As shown in [31], the topological defects induce v γ and v b from the vorticity σ. Then, the relative velocity between the photon and baryon fluids, v γ − v b , plays the main role in exciting the magnetic fields [33,34].…”

Section: )mentioning

confidence: 92%

“…are needed [31]. In this paper, we consider the string network as the external source and we need to consider the higher order approximation.…”

Section: Tight-coupling Approximationmentioning

confidence: 99%

“…Therefore we need δv (3) for an accurate calculation of δv (2) at the switching time [31] from the TCA to the full Boltzmann equations.…”

Section: Tight-coupling Approximationmentioning

confidence: 99%

“…Focusing on the vector mode that is responsible for the generation of magnetic fields, all of the perturbations are induced by vorticity σ from the string network. This assumption leads the first order TCA of the relative velocity to be zero δv (1) = 0; therefore, the second order TCA of the relative velocity δv (2) is the leading order of δv [31],…”

Section: Before Recombinationmentioning

confidence: 99%

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Primordial magnetic fields from the string network

Horiguchi

Ichiki

Sugiyama

2016

Prog. Theor. Exp. Phys.

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Cosmic strings are a type of cosmic defect formed by a symmetry-breaking phase transition in the early universe. Individual strings would have gathered to build a network, and their dynamical motion would induce scalar-, vector-and tensor-type perturbations. In this paper, we focus on the vector mode perturbations arising from the string network based on the one scale model and calculate the time evolution and the power spectrum of the associated magnetic fields. We show that the relative velocity between photon and baryon fluids induced by the string network can generate magnetic fields over a wide range of scales based on standard cosmology. We obtain the magnetic field spectrum before recombination as a 2 B(k, z) ∼ 4 × 10 −16 Gµ/((1 + z)/1000) 4.25 (k/Mpc −1 ) 3.5 Gauss on super-horizon scales, and a 2 B(k, z) ∼ 2.4 × 10 −17 Gµ/((1 + z)/1000) 3.5 (k/Mpc −1 ) 2.5 Gauss on sub-horizon scales in co-moving coordinates. This magnetic field grows up to the end of recombination, and has a final amplitude of approximately B ∼ 10 −17∼−18 Gµ Gauss at the k ∼ 1 Mpc −1 scale today. This field might serve as a seed for cosmological magnetic fields.

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Section: )mentioning

confidence: 92%

“…are needed [31]. In this paper, we consider the string network as the external source and we need to consider the higher order approximation.…”

Section: Tight-coupling Approximationmentioning

confidence: 99%

“…Therefore we need δv (3) for an accurate calculation of δv (2) at the switching time [31] from the TCA to the full Boltzmann equations.…”

Section: Tight-coupling Approximationmentioning

confidence: 99%

Section: Before Recombinationmentioning

confidence: 99%

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Primordial magnetic fields from the string network

Horiguchi

Ichiki

Sugiyama

2016

Prog. Theor. Exp. Phys.

Self Cite

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“…The standard model of inflation in the early Universe, namely, the single-field slow-roll inflation, predicts the existence of primordial gravitational waves (PGWs) that correspond to the tensor mode. The vector mode can be induced by cosmological magnetic fields [5,6], cosmological defects [7][8][9], or additional vector fields [10,11]. However, the amplitude of the vector mode generated in these models highly depends on their model parameters.…”

Section: Introductionmentioning

confidence: 99%

Observable cosmological vector mode in the dark ages

Saga

2016

Phys. Rev. D

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The second-order vector mode is inevitably induced from the coupling of first-order scalar modes in cosmological perturbation theory and might hinder a possible detection of primordial gravitational waves from inflation through 21cm lensing observations. Here, we investigate the weak lensing signal in 21cm photons emitted by neutral hydrogen atoms in the dark ages induced by the second-order vector mode by decomposing the deflection angle of the 21cm lensing signal into the gradient and curl modes. The curl mode is a good tracer of the cosmological vector and tensor modes since the scalar mode does not induce the curl one. By comparing angular power spectra of the 21cm lensing curl mode induced by the second-order vector mode and primordial gravitational waves whose amplitude is parametrized by the tensor-to-scalar ratio r, we find that the 21cm curl mode from the second-order vector mode dominates over that from primordial gravitational waves on almost all scales if r 10 −5 . If we use the multipoles of the power spectrum up to ℓmax = 10 5 and 10 6 in reconstructing the curl mode from 21cm temperature maps, the signal-to-noise ratios of the 21cm curl mode from the second-order vector mode achieve S/N ≈ 0.46 and 73, respectively. Observation of 21cm radiation is, in principle, a powerful tool to explore not only the tensor mode but also the cosmological vector mode.

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Manifestations of Dark Matter and Variations of the Fundamental Constants in Atoms and Astrophysical Phenomena

Stadnik

2017

Springer Theses

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We present an overview of recent developments in the detection of light bosonic dark matter, including axion, pseudoscalar axion-like and scalar dark matter, which form either a coherently oscillating classical field or topological defects (solitons). We emphasise new high-precision laboratory and astrophysical measurements, in which the sought effects are linear in the underlying interaction strength between dark matter and ordinary matter, in contrast to traditional detection schemes for dark matter, where the effects are quadratic or higher order in the underlying interaction parameters and are extremely small. New terrestrial experiments include measurements with atomic clocks, spectroscopy, atomic and solid-state magnetometry, torsion pendula, ultracold neutrons, and laser interferometry. New astrophysical observations include pulsar timing, cosmic radiation lensing, Big Bang nucleosynthesis and cosmic microwave background measurements. We also discuss various recently proposed mechanisms for the induction of slow 'drifts', oscillating variations and transient-in-time variations of the fundamental constants of Nature by dark matter, which offer a more natural means of producing a cosmological evolution of the fundamental constants compared with traditional dark energy-type theories, which invoke a (nearly) massless underlying field. Thus, measurements of variation of the fundamental constants gives us a new tool in dark matter searches.

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Primordial magnetic fields from self-ordering scalar fields

Cited by 10 publications

References 40 publications

Primordial magnetic fields from the string network

Primordial magnetic fields from the string network

Observable cosmological vector mode in the dark ages

Manifestations of Dark Matter and Variations of the Fundamental Constants in Atoms and Astrophysical Phenomena

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