Primordial Universe with radiation and Bose–Einstein condensate

Alvarenga, F. G.; Filho, L. G. Ferreira; Fracalossi, R.; Freitas, R. C.; Gonçalves, S. V. B.; Monerat, G. A.; Oliveira‐Neto, G.; Silva, E. V. Corrêa

doi:10.1016/j.dark.2019.100325

Cited by 3 publications

(3 citation statements)

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“…The literature is rich in the exploration of this possibility [13,14], which is very crucial to our understanding of the Universe. As postulated by Sikivie et al long ago [9], axions may indeed be the main components of dark matter and eventually reach thermal equilibrium, induced by gravity, to form a Bose-Einstein (BEC) condensate [17][18][19]. This is to be contrasted with the opinion of other authors who claim that the value of the galaxy phase-space density excludes the formation of a Bose-Einstein condensate [20] or that the rate of entropy creation apparently is not consistent with the gravitational thermalization rate [18].…”

Section: Axions In Cosmologymentioning

confidence: 95%

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On the Breaking of the U(1) Peccei–Quinn Symmetry and Its Implications for Neutrino and Dark Matter Physics

Civitarese

2024

Symmetry

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The Standard Model of electroweak interactions is based on the fundamental SU(2)weak × U(1)elect representation. It assumes massless neutrinos and purely left-handed massive W± and Z0 bosons to which one should add the massless photon. The existence, verified experimentally, of neutrino oscillations poses a challenge to this scheme, since the oscillations take place between at least three massive neutrinos belonging to a mass hierarchy still to be determined. One should also take into account the possible existence of sterile neutrino species. In a somehow different context, the fundamental nature of the strong interaction component of the forces in nature is described by the, until now, extremely successful representation based on the SU(3)strong group which, together with the confining rule, give a description of massive hadrons in terms of quarks and gluons. To this is added the minimal U(1) Higgs group to give mass to the otherwise massless generators. This representation may also be challenged by the existence of both dark matter and dark energy, of still unknown composition. In this note, we shall discuss a possible connection between these questions, namely the need to extend the SU(3)strong × SU(2)weak × U(1)elect to account for massive neutrinos and dark matter. The main point of it is related to the role of axions, as postulated by Roberto Peccei and Helen Quinn. The existence of neutral pseudo-scalar bosons, that is, the axions, has been proposed long ago by Peccei and Quinn to explain the suppression of the electric dipole moment of the neutron. The associated U(1)PQ symmetry breaks at very high energy, and it guarantees that the interaction of other particles with axions is very weak. We shall review the axion properties in connection with the apparently different contexts of neutrino and dark matter physics.

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Section: Axions In Cosmologymentioning

confidence: 95%

“…Axions may be a dominant part of the cold dark matter, as postulated by Sikivie and Yang in their original paper [9] and by other authors [15][16][17][18][19][20].…”

Section: Massive Axions In the Peccei And Quinn Picture And Neutrino-...mentioning

confidence: 99%

On the Breaking of the U(1) Peccei–Quinn Symmetry and Its Implications for Neutrino and Dark Matter Physics

Civitarese

2024

Symmetry

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“…The situation in which the behaviour of a quantum universe whose material content is composed of a barotropic fluid has already been widely explored in the scientific literature [6,7,8]. We also find cosmological models in which the material content of the universe is composed of two barotropic fluids [9,10].…”

Section: Introductionmentioning

confidence: 96%

Quantum Cosmology with Many Fluids and the Choice of Cosmological Time

Monerat¹,

Santos

Alvarenga

et al. 2019

Braz J Phys

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In this work we propose the quantization of a cosmological model describing the primordial universe filled with five barotropic fluids, namely: radiation, dust, vacuum, cosmic strings and domain walls. We intend to identify which fluid is best suited to provide phenomenologically the temporal variable in accordance with the observable universe. Through the Galerkin spectral method and the finite difference method in the Crank-Nicolson scheme (vacuum case), the cosmological solutions are obtained and compared. The vacuum case is especially interesting because it provides a tunneling transition mechanism from the quantum to the classical phase and the possibility of calculating quantum tunneling probabilities. PACS number(s): 98

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