Showing papers on "Big Rip published in 1989"
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TL;DR: A Friedmann-Robertson-Walker cosmology with energy density decreasing in expansion as 1/R-squared, where R is the Robertson-Walker scale factor, is studied in this paper.
Abstract: A Friedmann-Robertson-Walker cosmology with energy density decreasing in expansion as 1/R-squared, where R is the Robertson-Walker scale factor, is studied. In such a model the universe expands with constant velocity; hence the term coasting cosmology. Observational consequences of such a model include the age of the universe, the luminosity distance-redshift relation (the Hubble diagram), the angular diameter distance-redshift relation, and the galaxy number count as a function of redshift. These observations are used to limit the parameters of the model. Among the interesting consequences of the model are the possibility of an ever-expanding closed universe, a model universe with multiple images at different redshifts of the same object, a universe with Omega - 1 not equal to 0 stable in expansion, and a closed universe with radius smaller than 1/H(0).
118 citations
TL;DR: The ``3+1'' formalism of Thorne and Macdonald is applied to construct the linearized theory of a general-relativistic electron-positron plasma in the early Universe; it is found that the frequencies of the basic modes redshift like the frequency of a free photon.
Abstract: We apply the ``3+1'' formalism of Thorne and Macdonald to construct the linearized theory of a general-relativistic electron-positron plasma in the early Universe. Close formal correspondence between the theory of such plasmas and that of their special-relativistic counterparts is demonstrated. The time variation of the plasma modes due to the expansion of the background is determined for the case of a radiation-dominated Universe; it is found that the frequencies of the basic modes redshift like the frequency of a free photon. A simple kinetic argument is used to justify the neglect of creation and annihilation (collisional) effects. The formulation is sufficiently straightforward to be readily amenable to numerical implementation. Our results can be applied to the study of the origin of primordial intergalactic magnetic fields, as well as to the problem of matter fluctuations in the early Universe.
77 citations
TL;DR: In this paper, the Li-7(H-3,n)Be-9 reaction, previously neglected in nucleosynthesis determinations, was found to greatly increase the predicted abundance of Be-9 resulting from the big bang.
Abstract: The Li-7(H-3,n)Be-9 reaction, previously neglected in nucleosynthesis determinations, is found to greatly increase the predicted abundance of Be-9 resulting from the big bang. For a nonuniform density universe, a primordial Be-9/H-1 number density ratio of 10 to the -13th is obtained. It is noted that recent Be-9/H-1 measurements in Population II stars approach the nonuniform density universe value. 22 references.
71 citations
TL;DR: The problematical interpretation of the wave function of the Universe is circumvented by introducing an internal comoving model detector, which is an analogue of the DeWitt-Unruh detector in quantum field theory in curved space-time.
Abstract: As is well known, the wave function of the Universe dictated by the Wheeler-DeWitt equation has a difficulty in its probabilistic interpretation. In order to overcome this difficulty, we explore a theoretical possibility of the second quantization of the Universe, following the same passage historically taken for the Klein-Gordon particles and the Nambu-Goto strings. It turns out that multiple production of universes is an inevitable consequence even if the initial state is nothing. The problematical interpretation of the wave function of the Universe is circumvented by introducing an internal comoving model detector, which is an analogue of the DeWitt-Unruh detector in quantum field theory in curved space-time.
59 citations
TL;DR: In this paper, six modeles numeriques simulant la formation and l'evolution des structures a grande echelle de l'Univers are presented and analyzed.
Abstract: Presentation de six modeles numeriques simulant la formation et l'evolution des structures a grande echelle de l'Univers
56 citations
TL;DR: This work considers the possibility of universe creation for the special case where the universe emerges in a no-particle state and the probability of such a creation is computed from both the path-integral and operator formalisms.
Abstract: Third quantization leads to a Hilbert space containing a third-quantized vacuum in which no universes are present as well as multiuniverse states. We consider the possibility of universe creation for the special case where the universe emerges in a no-particle state. The probability of such a creation is computed from both the path-integral and operator formalisms.
48 citations
TL;DR: In this article, the notion of a typical quantum state for the universe is discussed and it appears that inflation is a typical property of solutions of the Wheeler-DeWitt equation.
44 citations
TL;DR: In this paper, the total decay probabilities for electron-positron pairs were evaluated in a spatially flat Robertson-Walker universe with time-reversed photon creation in a time-dependent external gravitational field.
38 citations
TL;DR: In this article, it is argued that the only sensible questions in this context are joint probabilities for the cosmological constant and the scale factor a (or other suitable observable) of an expanding universe.
26 citations
TL;DR: In this paper, the authors considered the possibility of transition of the current universe expansion to contraction, based on the fact that a homogeneous universe is structured into non-homogeneous units, the latter expanding as a whole.
Abstract: The author considers the possibility of transition of the current universe expansion to contraction. The considerations are based on the fact that a homogeneous Universe is structured into non-homogeneous units, the latter expanding as a whole. An analysis of the effects of these wholes on further development shows that in the future contractions may occur only locally; however, the current spatial expansion of the Universe cannot be replaced by a global contraction.
16 citations
01 Jan 1989
TL;DR: In this article, Fang Li Zhi, a leading Chinese astrophysicist and Li Shu Xian (co-author and wife) trace the advances in cosmology and recount experiences made by scientists in an easily comprehensible and often humorous manner.
Abstract: Creation of the Universe traces the development of the Big Bang theory, from the expansion of the universe to quantum cosmology, from the formation of large scale structure to the physics of the Planck era. Fang Li Zhi, a leading Chinese astrophysicist and Li Shu Xian (co-author and wife) trace the advances in cosmology and recount experiences made by scientists - their frustrations and hardships, hopes and joys - in an easily comprehensible and often humorous manner. Complex topics are elucidated with anecdotes from Eastern and Western philosophy.
CERN1
TL;DR: In this article, it is argued that if the present vacuum energy density ϱv exceeds some extremely small critical value ϱc (ϱcR∼10−107g cm−3 for chaotic inflation in the theory 1 2 m 2 φ 2 ), then the lifetime of mankind in the inflationary universe should be finite, even though the universe as a whole will exist without end.
TL;DR: In this paper, the evolution of scalar (density) perturbations in a baryondominated universe is comprehensively studied on the basis of a gauge-invariant method.
Abstract: The evolution of scalar (density) perturbations in a baryon-dominated universe is comprehensively studied on the basis of a gauge-invariant method. In particular, the residual anisotropies of the cosmic microwave background radiation are calculated and are compared with the recent observational upper limits. To the extent that the universe has not been reionized after recombination, the observed upper limits of the temperature anisotropies on small angular scales rule out the cosmological models without nonbaryonic dark matter. In turn, this would provide strong support for (nonbaryonic) dark matter, independently of the results of standard primordial nucleosynthesis. Reionization after recombination, if any, might allow an isocurvature baryonic universe as a viable model, only when the initial density power spectrum was very steep. 64 refs.
CERN1
TL;DR: In this paper, the authors constructed the quantum cosmology of an anistropic universe according to the "no-boundary" prescription of Hartle and Hawking, and showed it also implies that a large universe such as ours, is isotropic.
TL;DR: In this paper, general relativistic fluctuation-dissipation theorems are applied to a Friedman universe with bulk viscosity, and it is argued that a nonvanishing bulk viscoity in the very early universe might provide reasonable initial conditions for galaxy formation.
TL;DR: In this article, a generalized Kerr-NUT type metric is considered in connection with Einstein field equations corresponding to perfect fluid plus a pure radiation field, and a general scheme for obtaining the exact solutions of these field equations is developed.
Abstract: A generalized Kerr-NUT type metric is considered in connection with Einstein field equations corresponding to perfect fluid plus a pure radiation field. A general scheme for obtaining the exact solutions of these field equations is developed. Two physically meaningful particular cases are investigated in detail. One gives the field of a radiating Kerr particle embedded in the Einstein universe. The other solution may probably represent a deSitter-like universe pervaded by a pure radiation field.
TL;DR: A first-order phase transition is likely to have occurred in the early universe at the end of the quark era and the beginning of the hadron era as mentioned in this paper, which would have created large amplitude isothermal fluctuations in the distribution of baryon number in the universe.
TL;DR: It is shown that when the oscillations are damped the Universe becomes radiation dominated and inflation ends.
Abstract: The problem of the reheating of the Universe after inflation is considered. Our approach is based on the use, as first principles,'' of the renormalized version of (a) the evolution equation for the mean value of an interacting scalar field and (b) the semiclassical Einstein equations. We compute (for two different toy models) the characteristic time for the damping of the mean-value oscillations. We show that when the oscillations are damped the Universe becomes radiation dominated and inflation ends. The techniques used in this paper are those of quantum field theory in curved spacetime and can be generalized to more realistic models.
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TL;DR: The current status of theoretical cosmology is surveyed in this paper with a focus on the areas of overlap between astrophysics and particle physics, including the nature of the big bang, the production and survival of particles in the early universe, relic nucleons, dark matter and weakly interacting massive particles from the early universes, and primordial nucleosynthesis.
Abstract: The current status of theoretical cosmology is surveyed, with a focus on the areas of overlap between astrophysics and particle physics. Topics addressed include the nature of the big bang, the production and survival of particles in the early universe, relic nucleons, dark matter and weakly interacting massive particles from the early universe, and primordial nucleosynthesis. It is argued that the theoretically inferred nucleon density can account for the luminous (baryonic) matter observed in galaxies and part of the observed dark matter, but that the universe cannot be closed by nucleons alone. 41 refs.
01 Jan 1989
TL;DR: One of the simplest, yet most profound, questions we can ask about the universe is, How much stuff is in it, and further what is that stuff composed of? Needless to say, the answer to this question has very important implications for the evolution of the Universe, determining both the ultimate fate and the course of structure formation as discussed by the authors.
Abstract: One of the simplest, yet most profound, questions we can ask about the Universe is, How much stuff is in it, and further what is that stuff composed of? Needless to say, the answer to this question has very important implications for the evolution of the Universe, determining both the ultimate fate and the course of structure formation. Remarkably, at this late date in the history of the Universe we still do not have a definitive answer to this simplest of questions—although we have some very intriguing clues. It is known with certainty that most of the material in the Universe is dark, and we have the strong suspicion that the dominant component of material in the Cosmos is not baryons, but rather is exotic relic elementary particles left over from the earliest, very hot epoch of the Universe. If true, the Dark Matter question is a most fundamental one facing both particle physics and cosmology. The leading particle dark matter candidates are: the axion, the neutralino, and a light neutrino species. All three candidates are accessible to experimental tests, and experiments are now in progress. In addition, there are several dark horse, long shot, candidates, including the superheavy magnetic monopole and soliton stars.
TL;DR: In this article, the evolution of the scale factor of the universe is studied numerically by solving the coupled Einstein-matter equations for various initial configurations of the inflation-driving scalar field.
Abstract: We study initial conditions and mechanisms of the onset of inflation using the functional Schrodinger picture of quantum field theory in 1 + 2-dimensional Robertson-Walker spacetime. The evolution of the scale factor of the universe is studied numerically by solving the coupled Einstein-matter equations for various initial configurations of the inflation- driving scalar field. In this note we present a sample of our numerical results.
TL;DR: Stephen Hawking's proposal for the initial state of the Universe is applied to a rotating Bianchi type-IX minisuperspace model and it is said that for a small angular velocity the closed Friedmann-Robertson-Walker model is indeed the most probable initial state for the Universe.
Abstract: We apply Hawking's proposal for the initial state of the Universe to a rotating Bianchi type-IX minisuperspace model in order to examine the problem of rotation in a closed cosmology. Using the Feynman path-integral techniques instead of the Wheeler-DeWitt equation, we are able to say that for a small angular velocity the closed Friedmann-Robertson-Walker model is indeed the most probable initial state for the Universe.
TL;DR: In this paper, the convergence due to the gravititational-lens effects of the clumps, and the divergence due to less mass density outside the clump are analyzed.
Abstract: In comparison with a homogeneous universe, a clumpy universe possess two types of effects on geometrical optics: 1. the convergence due to the gravititational-lens effects of the clumps; 2. the divergence due to the less mass density outside the clumps. On the other hand, thermodynamics requires that the total effects are double offset. This give us an effective method to judge the rationality of various calculations of the lensing effect in a clumpy universe.
TL;DR: In this article, the evolution of weakly coupled scalar fields in the early universe is discussed and the classical evolution in a pre-inflationary radiation dominated universe is studied under which conditions the fields dynamically relax to configurations which gave inflation.
Abstract: The evolution of weakly coupled scalar fields in the early universe is discussed. Such fields will be out of thermal equilibrium, and their initial distribution will be inhomogeneous. We study the classical evolution in a pre-inflationary radiation dominated universe and discuss under which conditions the fields dynamically relax to configurations which gave inflation.
TL;DR: In this article, the authors used the topology of the distribution of matter in the universe to test the hypothesis that the structure in our universe grew by gravitational amplification of Gaussian fluctuations.
Abstract: Analysis of the topology of the distribution of matter in the universe provides information not found in correlation functions. Quantitative measures of the topology can be used to test the hypothesis that structure in our universe grew by gravitational amplification of Gaussian fluctuations.
01 Jan 1989
TL;DR: The early cosmologies (theories of the nature of the universe) that were developed before the time of Copernicus enforced that belief and made it exceedingly difficult and even dangerous to advocate anything that threatened the belief in this favored position of Earth.
Abstract: Until relatively recently in the history of civilization, we believed tenaciously that we occupy a special position in the scheme of things, and the early cosmologies (theories of the nature of the universe) that were developed before the time of Copernicus enforced that belief. If, as we then believed, mankind is important to the proper running of the universe, what was more natural than to conclude that Earth is at the very center of the universe and that all the other heavenly bodies were placed in the sky for the glorification of God and man? That all the naked-eye evidence seemed to agree with such a concept strengthened the hold of these early theories and made it exceedingly difficult and even dangerous to advocate anything that threatened the belief in this favored position of Earth.
01 Jan 1989
TL;DR: In this paper, an approach to the problem of large-scale structure of the universe is considered where an initial linear peculiar gravitational potential plays the crucial role, and the mechanisms of the generation of non-standard 1 (nonflat and non-Gaussian) initial perturbations at the inflationary stage are briefly discussed in terms of ϕ.
Abstract: The approach to the problem of large-scale structure of the Universe is considered where an initial linear peculiar gravitational potential \(\varphi (\vec x)\) plays the crucial role. The random field ϕ contains all information about the particular cosmological model. 1 Voids form around high peaks of ϕ, the large-scale streaming velocities of galaxies 1 are governed by ‘hills’ and ‘valleys’ of ϕ. The mechanisms of the generation of non-standard 1 (non-flat and non-Gaussian) initial perturbations at the inflationary stage are briefly discussed in terms of ϕ. 1
01 Jan 1989
TL;DR: In this paper, a model of the primordial scalar field theory, in which the metric tensor is a generalization of the metamodel tensor from electrodynamics in a medium, is discussed.
Abstract: The formulation of a model of the “primordial” scalar field theory, in which the metric tensor is a generalization of the metric tensor from electrodynamics in a medium, is discussed. The “spontaneous” splitting of this metric tensor into two distinct metric tensors gives rise to massless radiation and to massive particles.