A Planck-scale axion and SU(2) Yang–Mills dynamics: present acceleration and the fate of the photon

Giacosa, Francesco; Hofmann, Ralf

doi:10.1140/epjc/s10052-007-0214-x

Cited by 32 publications

(70 citation statements)

References 44 publications

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“…In the large-N limit, for which the model is renormalizable in a de Sitter geometry [19], the Hubble constant H vanishes for any fixed value of the renormalized cosmological constant. After integrating out the fermionic degrees of freedom we find that two composite isosinglet fields play a crucial role: a scalar field ρ is relevant for the early-time cosmology and for the above-mentioned relaxation of the vacuum energy, while a pseudoscalar field ϕ emerges as an axion field, which can play a crucial role for late-time cosmology, being responsible for the presently observed small but nonzero value of the dark energy [1,3,8,21]. In the evaluation of the effective potential for early cosmology care is needed in the choice of the regularization scheme.…”

Section: Discussionmentioning

confidence: 98%

A model for the very early universe

Giacosa¹,

Hofmann²,

Neubert³

2008

J. High Energy Phys.

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A model with N species of massless fermions interacting via (microscopic) gravitational torsion in de Sitter spacetime is investigated in the limit N → ∞. The U V (N ) × U A (N ) flavor symmetry is broken dynamically irrespective of the (positive) value of the induced four-fermion coupling. This model is equivalent to a theory with free but massive fermions fluctuating about the chiral condensate. When the fermions are integrated out in a way demonstrated long ago by Candelas and Raine, the associated gap equation together with the Friedmann equation predict that the Hubble parameter vanishes. Introducing a matter sector (subject to a finite gauge symmetry) as a source for subsequent cosmology, the neutral Goldstone field acquires mass by the chiral anomaly, resulting in a Planck-scale axion.

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Section: Discussionmentioning

confidence: 98%

A model for the very early universe

Giacosa¹,

Hofmann²,

Neubert³

2008

J. High Energy Phys.

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“…Our previous statements on anomalous largeangle CMB temperature-temperature correlations, obtained in the approximation p 2 = 0, remain valid. 1 For a feasibility discussion of this postulate see [1]. 2 The notion of a thermal ground state emerges upon the execution of a sufficiently local, selfconsistent spatial coarse-graining over interacting calorons and anticalorons of topological charge modulus unity [3,4].…”

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confidence: 99%

Thermal photon dispersion law and modified black-body spectra

Ludescher¹,

Hofmann²

2009

Ann. Phys.

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Based on the postulate that photon propagation is governed by an SU(2) gauge principle we numerically compute the one-loop dispersion for thermalized photon propagation on the radiatively induced mass shell. Formerly, the dispersion was addressed by assuming $p^2=0$. While this approximation turns out to be excellent for temperatures $\le 2 T_{\tiny{CMB}}$ the exact result exhibits a much faster (power-like) shrinking of the gap in the black-body spectral intensity with rising temperature. Our previous statements on anomalous large-angle CMB temperature-temperature correlations, obtained in the approximation $p^2=0$, remain valid.Comment: v2: 13 pages, 6 figures; sec. 2.1. added to explain effective theory; references added; matches journal published versio

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“…But if during CMB decoupling the vector modes V ± of SU(2) CMB actually play the role conventionally attributed to neutrinos then how do the latter vanish from the spectrum of relativistic degrees of freedom? In [39,40] we have proposed that neutrinos could be single, that is, non-selfintersecting center-vortex loops 6 (zero selfintersection number, N = 0) in the confining phases of pure SU(2) gauge theories whose Yang-Mills scales match the masses of charged leptons. Due to the absence of an explicit mass scale in the sector with N = 0 and void of interactions with an environment a single vortex loop would shrink to a round point [40] of zero mass and vanishing electric/magnetic multipoles.…”

Section: Cosmic Neutrinosmentioning

confidence: 99%

Thermodynamics of SU(2) quantum Yang-Mills theory and CMB anomalies

Hofmann

2014

EPJ Web of Conferences

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Abstract. A brief review of effective SU(2) Yang-Mills thermodynamics in the deconfining phase is given, including the construction of the thermal ground-state estimate in terms of an inert, adjoint scalar field φ, based on non-propagating (anti)selfdual field configurations of topological charge unity. We also discuss kinematic constraints on interacting propagating gauge fields implied by the according spatial coarse-graining, and we explain why the screening physics of an SU(2) photon is subject to an electricmagnetically dual interpretation. This argument relies on the fact that only (anti)calorons of scale parameter ρ ∼ |φ| −1 contribute to the coarse-graining required for thermalground-state emergence at temperature T . Thus, use of the effective gauge coupling e in the (anti)caloron action is justified, yielding the value for the latter at almost all temperatures. As a consequence, the indeterministic transition of initial to final plane waves caused by an effective, pointlike vertex is fundamentally mediated in Euclidean time by a single (anti)caloron being part of the thermal ground state. Next, we elucidate how a low-frequency excess of line temperature in the Cosmic Microwave Background (CMB) determines the value of the critical temperature of the deconfining-preconfining phase transition of an SU(2) Yang-Mills theory postulated to describe photon propagation, and we describe how, starting at a redshift of about unity, SU(2) photons collectively work 3D temperature depressions into the CMB. Upon projection along a line of sight, a given depression influences the present CMB sky in a cosmologically local way, possibly explaining the large-angle anomalies confirmed recently by the Planck collaboration. Finally, six relativistic polarisations residing in the SU(2) vector modes roughly match the number of degrees of freedom in cosmic neutrinos (Planck) which would disqualify the latter as radiation. Indeed, if interpreted as single center-vortex loops in confining phases of SU(2) Yang-Mills theories neutrino mass m ν solely arises by interactions with an environment. Cosmologically, the CMB represents this environment, and thus one would expect that m ν = ξT where ξ = O(1). In this model cosmic neutrinos are a small darkmatter contribution, conserved only together with the CMB fluid, influencing Baryonic Acoustic Oscillations during CMB decoupling. a

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A Planck-scale axion and SU(2) Yang–Mills dynamics: present acceleration and the fate of the photon

Cited by 32 publications

References 44 publications

A model for the very early universe

A model for the very early universe

Thermal photon dispersion law and modified black-body spectra

Thermodynamics of SU(2) quantum Yang-Mills theory and CMB anomalies

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