EQUATION OF STATE AND TEMPERATURE OF MASSIVE NONRELATIVISTIC BOSONS ARISING IN THE UNIVERSE AT THE FIRST STAGE OF REHEATING

1995 ◽  
Vol 10 (40) ◽  
pp. 3069-3076 ◽  
Author(s):  
I. DYMNIKOVA ◽  
M. KRAWCZYK

We consider heavy nonrelativistic bosons with masses M~MGUT which arise in the Universe during phase transitions with spontaneous symmetry breaking at the grand unification scale. In the frame of statistical mechanics approach with model-independent description of cosmological background we show that the process of emerging of massive GUT bosons looks like evaporation of a Bose condensate. First massive nonrelativistic bosons behave like ideal quantum degenerate Bose gas which has the Gibbons-Hawking temperature due to the presence of the de Sitter event horizon.

2009 ◽  
Vol 18 (09) ◽  
pp. 1331-1342 ◽  
Author(s):  
WEN ZHAO

We investigate the attractor solution in the coupled Yang–Mills field dark energy models with the general interaction term, and obtain the constraint equations for the interaction if the attractor solution exists. The research also shows that, if the attractor solution exists, the equation of state of dark energy must evolve from wy > 0 to wy ≤ -1, which is slightly suggested by the observation. At the same time, the total equation of state in the attractor solution is w tot = -1, the universe is a de Sitter expansion, and the cosmic big rip is naturally avoided. These features are all independent of the interacting forms.


2012 ◽  
Vol 27 (36) ◽  
pp. 1250210 ◽  
Author(s):  
I. BREVIK ◽  
V. V. OBUKHOV ◽  
K. E. OSETRIN ◽  
A. V. TIMOSHKIN

Specific dark energy models, leading to the Little Rip (LR) cosmology in the far future, are investigated. Conditions for the occurrence of LR in terms of the parameters present in the proposed equation of state for the dark energy cosmic fluid are studied. Estimates about the time needed before the occurrence of the small singularity in the standard LR model in which the universe approaches the de Sitter spacetime asymptotically, are given.


1998 ◽  
Vol 13 (19) ◽  
pp. 1539-1546
Author(s):  
F. BUCCELLA ◽  
O. PISANTI ◽  
L. ROSA

The possibility of generating the observed baryon asymmetry of the universe in an SO(10) gauge model with spontaneous symmetry breaking pattern [Formula: see text] is studied. We find it possible to generate a [Formula: see text], converting the leptonic number produced at the B- L breaking scale via the B+L violating processes mediated by sphalerons at the electroweak scale. The resulting picture is tested against the limit coming from experimental data: proton lifetime and neutrino oscillations.


Author(s):  
Edmund J. Copeland ◽  
T. W. B. Kibble

Cosmic strings are predicted by many field-theory models, and may have been formed at a symmetry-breaking transition early in the history of the universe, such as that associated with grand unification. They could have important cosmological effects. Scenarios suggested by fundamental string theory or M-theory, in particular the popular idea of brane inflation, also strongly suggest the appearance of similar structures. Here we review the reasons for postulating the existence of cosmic strings or superstrings, the various possible ways in which they might be detected observationally and the special features that might discriminate between ordinary cosmic strings and superstrings.


Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2076
Author(s):  
Priidik Gallagher ◽  
Tomi Koivisto

Notoriously, the two main problems of the standard ΛCDM model of cosmology are the cosmological constant Λ and the cold dark matter, CDM. This essay shows that both the Λ and the CDM arise as integration constants in a careful derivation of Einstein’s equations from first principles in a Lorentz gauge theory. The dark sector of the universe might only reflect the geometry of a spontaneous symmetry breaking that is necessary for the existence of spacetime and an observer therein.


Author(s):  
M. Sami ◽  
Radouane Gannouji

Spontaneous symmetry breaking is the foundation of electroweak unification and serves as an integral part of the model building beyond the standard model of particle physics and it also finds interesting applications in the late Universe. We review development related to obtaining the late cosmic acceleration from spontaneous symmetry breaking in the Universe at large scales. This phenomenon is best understood through Ginzburg–Landau theory of phase transitions which we briefly describe. Hereafter, we present elements of spontaneous symmetry breaking in relativistic field theory. We then discuss the “symmetron” scenario-based upon symmetry breaking in the late Universe which is realized by using a specific form of conformal coupling. However, the model is faced with “NO GO” for late-time acceleration due to local gravity constraints. We argue that the problem can be circumvented by using the massless [Formula: see text] theory coupled to massive neutrino matter. As for the early Universe, spontaneous symmetry breaking finds its interesting applications in the study of electroweak phase transition. To this effect, we first discuss in detail the Ginzburg–Landau theory of first-order phase transitions and then apply it to electroweak phase transition including technical discussions on bubble nucleation and sphaleron transitions. We provide a pedagogical exposition of dynamics of electroweak phase transition and emphasize the need to go beyond the standard model of particle physics for addressing the baryogenesis problem. Review ends with a brief discussion on Affleck–Dine mechanism and spontaneous baryogenesis. Appendixes include technical details on essential ingredients of baryogenesis, sphaleron solution, one-loop finite temperature effective potential and dynamics of bubble nucleation.


2017 ◽  
Vol 474 (3) ◽  
pp. 3516-3522 ◽  
Author(s):  
Yu-Yang Wang ◽  
F Y Wang

Abstract In this paper, we study an anisotropic universe model with Bianchi-I metric using Joint light-curve analysis (JLA) sample of Type Ia supernovae (SNe Ia). Because light-curve parameters of SNe Ia vary with different cosmological models and SNe Ia samples, we fit the SNe Ia light-curve parameters and cosmological parameters simultaneously employing Markov chain Monte Carlo method. Therefore, the results on the amount of deviation from isotropy of the dark energy equation of state (δ), and the level of anisotropy of the large-scale geometry (Σ0) at present, are totally model-independent. The constraints on the skewness and cosmic shear are −0.101 < δ < 0.071 and −0.007 < Σ0 < 0.008. This result is consistent with a standard isotropic universe (δ = Σ0 = 0). However, a moderate level of anisotropy in the geometry of the Universe and the equation of state of dark energy, is allowed. Besides, there is no obvious evidence for a preferred direction of anisotropic axis in this model.


2018 ◽  
Vol 4 (2) ◽  
Author(s):  
Édouard Brézin

Broken symmetries encompass a large number of different phenomena occurring at different scales. Édouard Brézin examines how symmetry has become central to understanding the organization of the universe.


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