scholarly journals MULTIVERSE: PHILOSOPHICAL REFLECTIONS ON THEORETICAL IDEAS AND EMPIRICAL DATA

2021 ◽  
pp. 5-13
Author(s):  
Iryna Dobronravova
Keyword(s):  
Scalar Field ◽  
Early Universe ◽  
Possible Worlds ◽  
Relativistic Quantum ◽  
Vacuum State ◽  
High Energy ◽  
Big Bang ◽  
Ontological Status ◽  
Many Worlds ◽  
Original State

The cosmological conception of the Multiverse was formulated based on unitary gauge theories in the Physics of high energy. Theoretically expected, the quantum fluctuations of the original scalar field in a vacuum state and different variants of local symmetries breaking in the process of Early Universe expansion were the reasons for the cosmological idea of many possible worlds or Multiverse. Together with the inflationary cosmological model, these ideas successfully solved the problems of Big Bang theory with an explanation of observable quasi-Euclidean geometry in our world and isotropy and homogeneity of space on a mega-scale. New observational data, especially discovery of accelerative widening of space, so as the problem of dark matter and dark energy put for cosmology the new questions. These questions need to be philosophically comprehended. Professor Sergiy Krymsky offered an interesting understanding of the notion of "matter" in the situation of many worlds in the 80s. He considered each of the possible worlds as "matter, kept in its specificity", which existed in its own space and time with its set of elements, physical laws and constants. However, his considering the original vacuum state of scalar field as non-being is not satisfied because its heterogeneity defines further places for becoming of Galaxies. In this article, the author considers the ideas about the ontological status of the original state of the Early Universe in modern cosmological Multiverse theories and discusses the possible antinomies in these transcendental ideas and their difference from Kantian ones. Experience of solution the Kant’s antinomy in history of physics was taken into account. It was the second antinomy of discreetness / continuality. The solution was haven get in a way proposed by Kant, namely with empirical research and their theoretical explanations. Cosmological application of High Energy Physics gets it to transcendental ideas area, namely to the problem of our world becoming one of the possible worlds, just as a particular variant of first Kant's antinomy. However, formulation of antinomy connected with consideration of the ontological status of original state for becoming of our world has other categorical expressions than Kantian one. The front position belongs here to categories of possibility and actuality, which Kant did not include in the area of transcendental ideas, thinking that the contingency, connecting with possibility, must be changed by inevitable necessity in cognitive progress. On the contrary, contingency has the main place in modern cosmological scenarios, depending on multiple possibilities. So categories of possibility and actuality in the foundations of scientific theories need special attention. Now it touches upon at least two moments: the virtual particles as abstract objects of relativistic quantum theories and to the problem of understanding the ontological status of category "matter" in foundations of many world cosmology in the context of relations to categories "possibility", "actuality" and "reality".

Tom Kibble and the early universe as the ultimate high energy experiment

2014 ◽  
Vol 29 (06) ◽  
pp. 1430015
Author(s):  
Neil Turok
Keyword(s):  
Early Universe ◽  
Domain Walls ◽  
Initial Conditions ◽  
High Energy ◽  
Big Bang ◽  
Cyclic Universe ◽  
Exponential Expansion ◽  
Physical Laws ◽  
The Big Bang ◽  
New Evidence

Tom Kibble pioneered the idea that there were one or more symmetry breaking phase transitions in the very early universe, at which defects like monopoles, strings and domain walls would have formed. In the context of grand unified theories, or their extensions, this idea remains compelling: observing these defects would be one of the very few ways of directly confirming the theories. In contrast, inflationary theory invoked a strongly supercooled transition driving a period of exponential expansion which would sweep all such defects away. If inflation terminated slowly, quantum vacuum fluctuations would be amplified and stretched to cosmological scales, forming density variations of just the character required to explain the formation of galaxies. The ensuing paradigm has dominated cosmology for the last three decades. However, basic problems in the scenario remain unresolved. Extreme tuning both of the initial conditions and of the physical laws are required. There are many different versions, each with slightly different predictions. Finally, inflation brought with it the theory of a "multiverse" — a universe containing infinite number of different, infinite, universes — while providing no "measure" or means of calculating the probability of observing any one of them. I will discuss an alternative to inflation, in which the big bang was a bounce from a previous contracting epoch. The discovery of the Higgs boson at the LHC has provided new evidence for such a picture by showing that, within the minimal standard model, our current vacuum is metastable. This opens the door to a cyclic universe scenario in which the electroweak Higgs plays a central role.

NONLINEAR RESONANCE IN THE VERY EARLY UNIVERSE: SOUNDS OF THE PRIMORDIAL MUSIC

2008 ◽  
Vol 17 (13n14) ◽  
pp. 2459-2465
Author(s):  
H. P. DE OLIVEIRA ◽  
I. DAMIÃO SOARES ◽  
E. V. TONINI
Keyword(s):  
Scalar Field ◽  
Early Universe ◽  
Crucial Role ◽  
Cellular Structure ◽  
Degrees Of Freedom ◽  
Nonlinear Resonance ◽  
High Energy ◽  
Kam Tori ◽  
Field Equations ◽  
The Universe

Nonlinear resonance is ubiquitous in nature. Resonance is relevant to understanding phenomena in quite distinct areas such as music, cellular structure, and astrophysics, and in the very early universe. In order to see the crucial role played by resonance in cosmology, we assume that closed FRW universes with a massive inflaton field evolve according to the field equations that contain additional terms arising from high energy corrections to cosmological scenarios. As a consequence, nonsingular bounces in the early evolution of the universe are produced. We have shown that in narrow windows of the parameter space of the models, nonlinear resonance phenomena of KAM tori occur and lead to the destruction of those tori that trap the inflaton, resulting in the escape of the universe into inflation. These resonance windows are labeled by an integer n ≥ 2; n is related to the ratio of the frequencies in the scale factor/scalar field degrees of freedom.

scholarly journals Relativistic Cosmology with an Introduction to Inflation

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 276
Author(s):  
Muhammad Zahid Mughal ◽  
Iftikhar Ahmad ◽  
Juan Luis García Guirao
Keyword(s):  
Standard Model ◽  
Early Universe ◽  
Large Scale ◽  
Initial Conditions ◽  
Big Bang ◽  
Relativistic Cosmology ◽  
The Standard Model ◽  
Big Bang Model ◽  
The Big Bang ◽  
The Universe

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.

Scalar field fluctuations in the early universe

1988 ◽  
Vol 303 (4) ◽  
pp. 713-727 ◽  
Author(s):  
K. Enqvist ◽  
K.W. Ng ◽  
K.A. Olive
Keyword(s):  
Scalar Field ◽  
Early Universe ◽  
Field Fluctuations

scholarly journals QUINTESSENCE: A MINI-REVIEW

2008 ◽  
Vol 23 (17n20) ◽  
pp. 1252-1265 ◽  
Author(s):  
JÉRÔME MARTIN
Keyword(s):  
Scalar Field ◽  
High Energy Physics ◽  
Physical Nature ◽  
High Energy ◽  
Accelerated Expansion ◽  
Ordinary Matter ◽  
Chameleon Effect ◽  
Tests Of Gravity ◽  
Energy Physics

Models where the accelerated expansion of our Universe is caused by a quintessence scalar field are reviewed. In the framework of high energy physics, the physical nature of this field is discussed and its interaction with ordinary matter is studied and explicitly calculated. It is shown that this coupling is generically too strong to be compatible with local tests of gravity. A possible way out, the chameleon effect, is also briefly investigated.

Gravitational waves: A probe to the physics in the early universe

2015 ◽  
Vol 30 (28n29) ◽  
pp. 1545005
Author(s):  
Qing-Guo Huang
Keyword(s):  
Quantum Theory ◽  
Gravitational Waves ◽  
Early Universe ◽  
Upper Bound ◽  
Planck Scale ◽  
Big Bang ◽  
Planck Data ◽  
Inflationary Scenario ◽  
Fundamental Scale ◽  
The Big Bang

Gravitational waves can escape from the big bang and can be taken as a probe to the physics, in particular the inflation, in the early universe. Planck scale is a fundamental scale for quantum theory of gravity. Requiring the excursion distance of inflaton in the field space during inflation yields an upper bound on the tensor-to-scalar ratio. For example, [Formula: see text] for [Formula: see text]. In the typical inflationary scenario, we predict [Formula: see text] and [Formula: see text] which are consistent with Planck data released in 2015 quite well. Subtracting the contribution of thermal dust measured by Planck, BICEP2 data implies [Formula: see text] which is the tightest bound on the tensor-to-scalar ratio from current experiments.

scholarly journals BORN–INFELD COSMOLOGIES

2000 ◽  
Vol 15 (27) ◽  
pp. 4341-4353 ◽  
Author(s):  
RICARDO GARCÍA-SALCEDO ◽  
NORA BRETÓN
Keyword(s):  
Electromagnetic Field ◽  
Early Universe ◽  
Big Bang ◽  
Linear Case ◽  
Conformal Metric ◽  
Curvature Invariants ◽  
Metric Function ◽  
Big Bang Singularity

We present a model for an inhomogeneous and anisotropic early universe filled with a nonlinear electromagnetic field of Born–Infeld (BI) type. The effects of the BI field are compared with the linear case (Maxwell). Since the curvature invariants are well behaved then we conjecture that our model does not present an initial big bang singularity. The existence of the BI field modifies the curvature invariants at t=0 as well as sets bounds on the amplitude of the conformal metric function.

scholarly journals Beginning of Universe through large field hybrid inflation

2015 ◽  
Vol 30 (21) ◽  
pp. 1550106 ◽  
Author(s):  
Tatsuo Kobayashi ◽  
Osamu Seto
Keyword(s):  
Gravitational Wave ◽  
Early Universe ◽  
High Energy ◽  
Wave Mode ◽  
Energy Scale ◽  
Large Field ◽  
Tensor Perturbation ◽  
Expectation Value ◽  
Hybrid Inflation ◽  
High Energy Scale

Recent detection of B-mode polarization induced from tensor perturbations by the BICEP2 experiment implies the so-called large field inflation, where an inflaton field takes super-Planckian expectation value during inflation, at a high energy scale. We show however, if another inflation follows hybrid inflation, the hybrid inflation can generate a large tensor perturbation with not super-Planckian but Planckian field value. This scenario would relax the tension between BICEP2 and Planck concerning the tensor-to-scalar ratio, because a negative large running can also be obtained for a certain number of e-fold of the hybrid inflation. A natural interpretation of a large gravitational wave mode with or without the scalar spectral running might be multiple inflation in the early Universe.

scholarly journals PRE-INFLATION IN THE PRESENCE OF CONFORMAL COUPLING

2004 ◽  
Vol 19 (11) ◽  
pp. 807-816
Author(s):  
APOSTOLOS KUIROUKIDIS ◽  
DEMETRIOS B. PAPADOPOULOS
Keyword(s):  
Scalar Field ◽  
Exact Solutions ◽  
Hubble Parameter ◽  
Field Potential ◽  
Critical Value ◽  
Big Bang ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Conformal Parameter ◽  
Flrw Universe

We consider a massless scalar field, conformally coupled to the Ricci scalar curvature, in the pre-inflation era of a closed FLRW Universe. The scalar field potential can be of the form of the Coleman–Weinberg one-loop potential, which is flat at the origin and drives the inflationary evolution. For positive values of the conformal parameter ξ, less than the critical value ξ c =(1/6), the model admits exact solutions with nonzero minimum scale factor and zero initial Hubble parameter. Thus these solutions can be matched smoothly to the so-called Pre-Big-Bang models. At the end of this pre-inflation era one can match inflationary solutions by specifying the form of the potential and the whole solution is of the class C(1).

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