scholarly journals SCALAR FIELD COSMOLOGY II: SUPERFLUIDITY, QUANTUM TURBULENCE, AND INFLATION

2012 ◽  
Vol 27 (26) ◽  
pp. 1250154 ◽  
Author(s):  
KERSON HUANG ◽  
HWEE-BOON LOW ◽  
ROH-SUAN TUNG

We generalize the big bang model in a previous paper by extending the real vacuum scalar field to a complex vacuum scalar field, within the FLRW framework. The phase dynamics of the scalar field, which makes the universe a superfluid, is described in terms of a density of quantized vortex lines, and a tangle of vortex lines gives rise to quantum turbulence. We propose that all the matter in the universe was created in the turbulence, through reconnection of vortex lines, a process necessary for the maintenance of the vortex tangle. The vortex tangle grows and decays, and its lifetime is the era of inflation. These ideas are implemented in a set of closed cosmological equations that describe the cosmic expansion driven by the scalar field on the one hand, and the vortex–matter dynamics on the other. We show how these two aspects decouple from each other, due to a vast difference in energy scales. The model is not valid beyond the inflation era, but the universe remains a superfluid afterwards. This gives rise to observable effects in the present universe, including dark matter, galactic voids, nonthermal filaments, and cosmic jets.

2019 ◽  
Vol 34 (34) ◽  
pp. 1950283 ◽  
Author(s):  
Saumya Ghosh ◽  
Sunandan Gangopadhyay ◽  
Prasanta K. Panigrahi

In this paper, we perform the Wheeler–DeWitt quantization for Bianchi type I anisotropic cosmological model in the presence of a scalar field minimally coupled to the Einstein–Hilbert gravity theory. We also consider the cosmological (perfect) fluid to construct the matter sector of the model whose dynamics plays the role of time. After obtaining the Wheeler–DeWitt equation from the Hamiltonian formalism, we then define the self-adjointness relations properly. Doing that, we proceed to get a solution for the Wheeler–DeWitt equation and construct a well-behaved wave function for the universe. The wave packet is next constructed from a superposition of the wave functions with different energy eigenvalues together with a suitable weight factor which renders the norm of the wave packet finite. It is then concluded that the Big-Bang singularity can be removed in the context of quantum cosmology.


2007 ◽  
Vol 3 (S249) ◽  
pp. 325-328
Author(s):  
T. Hara ◽  
S. Kunitomo ◽  
M. Shigeyasu ◽  
D. Kajiura

AbstractRecently, it has been observed the extreme metal-poor stars in the Galactic halo, which must be formed just after Pop III objects. On the other hand, the first gas clouds of mass ∼ 106 M⊙ are supposed to be formed at z ∼ 10, 20, and 30 for the 1σ, 2σ and 3σ, where the density perturbations are assumed of the standard ΛCDM cosmology. Usually it is approximated that the distribution of the density perturbation amplitudes is gaussian where σ means the standard deviation. If we could apply this gaussian distribution to the extreme small probability, the gas clouds would be formed at z ∼40, 60, and 80 for the 4σ, 6σ, and 8σ where the probabilities are approximately 3 × 10−5, 10−9, and 10−15. Within our universe, there are almost ∼ 1016 (∼ 1022M⊙/106M⊙) clouds of mass 106M⊙. Then the first gas clouds must be formed around z ∼ 80, where the time is ∼ 20 Myr (∼ 13.7/(1 + z)3/2 Gyr). Even within our galaxy, there are ∼ 105 (∼ 1011M⊙/106M⊙) clouds, then the first gas clouds within our galaxy must be formed around z ∼ 40, where the time is ∼ 54 Myr (∼ 13.7/(1+z)3/2Gyr).The evolution time for massive star (∼ 102M⊙) is ∼ 3 Myr and the explosion of the massive supernova distributes the metal within a cloud. The damping time of the supernova shock wave in the adiabatic and isothermal era is several Myr and stars of the second generation (Pop II) are formed within a free fall time ∼ 20 Myr. Even if the gas cloud is metal poor, there is a lot of possibility to form the planets around such stars. The first planetary systems could be formed within ∼ 6 × 107 years after the Big Bang in the universe. Even in our galaxies, the first planetary systems could be formed within ∼ 1.7 × 108 years. If the abundance of heavy elements such as Fe is small compared to the elements of C, N, O, the planets must be the one where the rock fraction is small. It is interesting to wait the observations of planets around metal-poor stars. For the panspermia theory, the origin of life could be expected in such systems.


2006 ◽  
Vol 190 ◽  
pp. 15-15
Author(s):  
D CASTELVECCHI
Keyword(s):  
Big Bang ◽  

Author(s):  
Jan Zalasiewicz

This is the story of a single pebble. It is just a normal pebble, as you might pick up on holiday - on a beach in Wales, say. Its history, though, carries us into abyssal depths of time, and across the farthest reaches of space. This is a narrative of the Earth's long and dramatic history, as gleaned from a single pebble. It begins as the pebble-particles form amid unimaginable violence in distal realms of the Universe, in the Big Bang and in supernova explosions and continues amid the construction of the Solar System. Jan Zalasiewicz shows the almost incredible complexity present in such a small and apparently mundane object. Many events in the Earth's ancient past can be deciphered from a pebble: volcanic eruptions; the lives and deaths of extinct animals and plants; the alien nature of long-vanished oceans; and transformations deep underground, including the creations of fool's gold and of oil. Zalasiewicz demonstrates how geologists reach deep into the Earth's past by forensic analysis of even the tiniest amounts of mineral matter. Many stories are crammed into each and every pebble around us. It may be small, and ordinary, this pebble - but it is also an eloquent part of our Earth's extraordinary, never-ending story.


Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 276
Author(s):  
Muhammad Zahid Mughal ◽  
Iftikhar Ahmad ◽  
Juan Luis García Guirao

In this review article, the study of the development of relativistic cosmology and the introduction of inflation in it as an exponentially expanding early phase of the universe is carried out. We study the properties of the standard cosmological model developed in the framework of relativistic cosmology and the geometric structure of spacetime connected coherently with it. The geometric properties of space and spacetime ingrained into the standard model of cosmology are investigated in addition. The big bang model of the beginning of the universe is based on the standard model which succumbed to failure in explaining the flatness and the large-scale homogeneity of the universe as demonstrated by observational evidence. These cosmological problems were resolved by introducing a brief acceleratedly expanding phase in the very early universe known as inflation. The cosmic inflation by setting the initial conditions of the standard big bang model resolves these problems of the theory. We discuss how the inflationary paradigm solves these problems by proposing the fast expansion period in the early universe. Further inflation and dark energy in fR modified gravity are also reviewed.


2019 ◽  
Vol 127 ◽  
pp. 02009
Author(s):  
Boris Shevtsov

Nonlinear oscillations in the dynamic system of gravitational and material fields are considered. The problems of singularities and caustics in gravity, expansion and baryon asymmetry of the Universe, wave prohibition of collapse into black holes, and failure of the Big Bang concept are discussed. It is assumed that the effects of the expansion of the Universe are coupling with the reverse collapse of dark matter. This hypothesis is used to substantiate the vortex and fractal structures in the distribution of matter. A system of equations is proposed for describing turbulent and fluctuation processes in gravitational and material fields. Estimates of the di usion parameters of such a system are made in comparison with the gravitational constant.


1999 ◽  
Vol 35 (1) ◽  
pp. 57-72 ◽  
Author(s):  
WILLIAM LANE CRAIG

John Taylor complains that the Kalam cosmological argument gives the appearance of being a swift and simple demonstration of the existence of a Creator of the universe, whereas in fact a convincing argument involving the premiss that the universe began to exist is very difficult to achieve. But Taylor's proffered defeaters of the premisses of the philosophical arguments for the beginning of the universe are themselves typically undercut due to Taylor's inadvertence to alternatives open to the defender of the Kalam arguments. With respect to empirical confirmation of the universe's beginning Taylor is forced into an anti-realist position on the Big Bang theory, but without sufficient warrant for singling out the theory as non-realistic. Therefore, despite the virtue of simplicity of form, the Kalam cosmological argument has not been defeated by Taylor's all too swift refutation.


2012 ◽  
Vol 44 (1) ◽  
pp. 3-36 ◽  
Author(s):  
Helge Kragh

The standard model of modern cosmology is known as the hot big bang, a name that refers to the initial state of the universe some fourteen billion years ago. The name Big Bang introduced by Fred Hoyle in 1949 is one of the most successful scientific neologisms ever. How did the name originate and how was it received by physicists and astronomers in the period leading up to the hot big bang consensus model in the late 1960s? How did it reflect the meanings of the origin of the universe, a concept that predates the name by nearly two decades? Contrary to what is often assumed, the name was not an instant success—it took more than twenty years before Big Bang became a household word in the scientific community. When it happened, it was used with different connotations, as is still the case. Moreover, it was used earlier and more frequently in popular than in scientific contexts, and not always relating to cosmology. It turns out that Hoyle’s celebrated name has a richer and more surprising history than commonly assumed and also that the literature on modern cosmology and its history includes many common mistakes and errors. An etymological approach centering on the name Big Bang provides supplementary insight to the historical understanding of the emergence of modern cosmology.


2011 ◽  
Vol 20 (06) ◽  
pp. 1039-1051 ◽  
Author(s):  
NINFA RADICELLA ◽  
MAURO SERENO ◽  
ANGELO TARTAGLIA

The cosmic defect theory has been confronted with four observational constraints: primordial nuclear species abundances emerging from the big bang nucleosynthesis; large scale structure formation in the Universe; cosmic microwave background acoustic scale; luminosity distances of type Ia supernovae. The test has been based on a statistical analysis of the a posteriori probabilities for three parameters of the theory. The result has been quite satisfactory and such that the performance of the theory is not distinguishable from that of the ΛCDM theory. The use of the optimal values of the parameters for the calculation of the Hubble constant and the age of the Universe confirms the compatibility of the cosmic defect approach with observations.


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