Showing papers on "Big Rip published in 1993"
Book•
01 Jan 1993
TL;DR: In this paper, the Friedmann model is used to model the growth of linear perturbations in the universe and the evolution of high redshift objects in the microwave background radiation.
Abstract: Preface Part I. The Smooth Universe: 1. Introducing the Universe 2. The Friedmann model 3. Thermal history of the Universe Part II. The Clumpy Universe: 4. Growth of linear perturbations 5. Statistical properties of the density fluctuations 6. The microwave background radiation 7. The linear theory: velocity fields 8. The non-linear evolution 9. The non-linear theory: high redshift objects Part III. Towards a More Complete Picture: 10. The origin of initial perturbations 11. Dark matter 12. Epilogue Appendices Notes and references Index.
1,181 citations
TL;DR: In this paper, it was shown that it is possible to realize an inflationary scenario even without conversion of the false-vacuum energy to radiation, and that the universe comes to the deflationary stage with a scale factor a(t)∞t 1 3.
241 citations
TL;DR: Large-scale cosmic microwave background temperature fluctuations are calculated for a universe with the topology of a 3-torus and it is found that a topologically ``small'' universe is no longer an interesting cosmological model.
Abstract: Large-scale cosmic microwave background temperature fluctuations are calculated for a universe with the topology of a 3-torus. In such a universe only perturbations which are harmonics of the fundamental mode are permitted. By comparison with data from the Cosmic Background Explorer satellite, we find that the minimum (comoving) scale of a cubic toroidal universe is 2400${\mathit{h}}^{\mathrm{\ensuremath{-}}1}$ Mpc for an n=1 inflationary model. This is approximately an order of magnitude greater than previous limits and 80% of the horizon scale, implying that a topologically ``small'' universe is no longer an interesting cosmological model.
107 citations
TL;DR: The consequences of the no-boundary proposal, the only reasonably complete set of boundary conditions that has been put forward, are analyzed and it is found that gravitational wave perturbations have an amplitude that remains in the linear regime at all times and is roughly time symmetric about the time of maximum expansion.
Abstract: It is argued that the observed thermodynamic arrow of time must arise from the boundary conditions of the Universe. We analyze the consequences of the no-boundary proposal, the only reasonably complete set of boundary conditions that has been put forward. We study perturbations of a Friedmann model containing a massive scalar field, but our results should be independent of the details of the matter content. We find that gravitational wave perturbations have an amplitude that remains in the linear regime at all times and is roughly time symmetric about the time of maximum expansion. Thus gravitational wave perturbations do not give rise to an arrow of time. However, density perturbations behave very differently. They are small at one end of the Universe's history, but grow larger and become nonlinear as the Universe gets larger. Contrary to an earlier claim, the density perturbations do not get small again at the other end of the Universe's history. They therefore give rise to a thermodynamic arrow of time that points in a constant direction while the Universe expands and contracts again. The arrow of time does not reverse at the point of maximum expansion. One has to appeal to the weak anthropic principle to explain why we observe the thermodynamic arrow to agree with the cosmological arrow, the direction of time in which the Universe is expanding.
74 citations
TL;DR: In this article, it was shown that the position of the observed minimum depends sensitively on the value of the cosmological constant, Lambda, in a flat universe, and that the sensitivity to a nonzero Lambda is compared to the sensitivity of Lambda in an open universe.
Abstract: The lensing effect of curved space, which can cause the angular diameter of a fixed reference length seen on the sky to reach a minimum and then increase with redshift, has recently been claimed to provide evidence, using compact radio sources, for a q sub 0 = 1/2 expansion. We show here that this relation, in particular the position of the observed minimum, depends sensitively on the value of the cosmological constant, Lambda, in a flat universe. The sensitivity to a nonzero Lambda in a flat universe is compared to the sensitivity to q sub 0 in an open universe without a cosmological constant. The reported results could provide the strongest available limit on the cosmological constant in a flat universe (and on Omega in an open universe) and so we explore how uncertainties in distance measures and evolution of the sources can affect the results. Evolution of less than 30 percent in source size for z of less than 2 can completely alter the results, and so must be convincingly ruled out if this technique is to provide a new tool for cosmology.
29 citations
TL;DR: In this paper, the authors argue that the existing observational data offer strong evidence against recent versions of time-symmetric universe models, assuming the universe is essentially transparent on the future light cone.
Abstract: If the arrow of time reverses in a recontracting universe it could produce observable electromagnetic effects. The authors argue that the existing observational data offer strong evidence against recent versions of time-symmetric universe models, assuming the universe is essentially transparent on the future light cone. They investigate this assumption for a simple recontracting Friedmann model.
18 citations
TL;DR: The coupledDirac-Einstein equations for a homogeneous isotropic space-time forbid a closed universe but lead to the standard cosmological model for aflat universe.
Abstract: The coupledDirac-Einstein equations for a homogeneous isotropic space-time forbid aclosed universe but lead to the standard cosmological model for aflat universe. Therefore only theopen universe is left as a nontrivial situation. There some of the desired cosmological effects emerge in a natural way:inflation, creation ex nihilo, etc.
16 citations
TL;DR: The Cosmic Background Explorer satellite has recently made the most accurate measurement of the temperature of the universe, determining it to be 2.726 � 0.01 kelvin.
Abstract: The Cosmic Background Explorer satellite has recently made the most accurate measurement of the temperature of the universe, determining it to be 2.726 ± 0.01 kelvin. In trying to understand why the temperature has this value, one is led to discover the most fundamental features of the universe—an early, radiation-dominated epoch, enormous entropy per nucleon, synthesis of the light elements around 3 minutes after the bang, and a small excess of matter over antimatter—as well as some of the most pressing issues in cosmology today—the development of structure in the universe and the identification of the nature of the ubiquitous dark matter.
16 citations
TL;DR: In this paper, it was shown that energy and momentum of a closed Friedmann universe are undetermined and that one can attach to such a universe a definite amount of the superenergy.
16 citations
TL;DR: It is shown that fluctuations of the third quantization of a closed Friedmann-Robertson-Walker universe field rapidly decrease in the course of cosmic expansion.
Abstract: We study the third quantization of a closed Friedmann-Robertson-Walker universe with a cosmological constant by using the functional Schrodinger equation. It is shown that fluctuations of the thirdquantized universe field rapidly decrease in the course of cosmic expansion
15 citations
TL;DR: In this paper, the case of a similar, but spatially flat, universe (k = 0) is investigated, where there is an initial geometric singularity (the scale factorR = 0), but not a physical one, since the initial density is finite.
Abstract: Recently a homogeneous cosmological model free from singularities was proposed, based on the general relativity theory. It described a closed universe (k = +1), initially filled with prematter, characterized by a density ρ equal to the Planck density and a pressureP = −ρ, and undergoing oscillations. In the present work the case of a similar, but spatially flat, universe (k = 0) is investigated. In this case there is an initial geometric singularity (the scale factorR = 0), but not a physical one, since the initial density is finite. This universe begins its existence at a timet = −∞ and, after going through the prematter and radiation-dominated eras, reaches the matter-dominated state and continues to expand indefinitely.
TL;DR: In this paper, a possible scheme of inflationary scenario at an early stage of the universe during the radiation dominated era by introducing a local Lorentz symmetry violating term in the space-time torsion of Einstein-Cartan action in E(4,1) space was shown.
Abstract: We have shown here, a possible scheme of inflationary scenario at an early stage of the universe during the radiation dominated era by introducing a local Lorentz symmetry violating term in the space-time torsion of Einstein-Cartan action in E(4,1) space. This 'additional' mechanism for producing inflation may also suggest the answer to the question of the local relative abundance of particles over antiparticles in the observed universe.
TL;DR: In this paper, the Kolmogoroff-Sinai entropy rate of the universe evolves in inverse proportion to the temperature, which results from a combination of nonlinear dynamics and quantum theory.
Abstract: Information in the universe evolves according to a nonlinear law, which results from a combination of nonlinear dynamics and quantum theory The Kolmogoroff-Sinai entropy rate of the Universe evolves in inverse proportion to the temperature Since the evolution of temperature is known from standard cosmology, the time dependence of the universal entropy rate can be determined and the temporal evolution of the universal information content can be calculated Information starts growing at the enormous rate of 1044 bits per second from an initial value of at least 2π (seven) bits at Planck time However, it reaches its contemporary value only if one or more inflationary phases have been passed by the Universe in the course of its evolution
TL;DR: In this paper, the authors proposed that the spatial topology of the universe can be detected by cosmic background radiation (CBR), because the amplitudes of the spherical harmonic expansion of CBR anisotropy are sensitively dependent on the size of the observable universe.
Abstract: A few years ago, we proposed that the spatial topology of the universe can be detected by cosmic background radiation (CBR), because the amplitudes of the spherical harmonic expansion of CBR anisotropy are sensitively dependent on the size of the universe. Recently, this method has been applied to study the size of a T3 universe by using the COBE-DMR data of CBR temperature fluctuation. The new result of the lower limit to the cosmologically spatial size is found to be larger than the old values by a factor of about 5. Therefore, the model of cubic T3 small universe can be ruled out. This paper is a summary of this progress. The significance and remained problems of the spatial topology of the universe have also been discussed.
01 Jan 1993
TL;DR: The spectra of distant quasars show far too many absorption-line features to be accounted for by the local galaxy population as mentioned in this paper, leading to the conclusion that there are many more galaxies than we would have expected from extrapolation of observations of the nearby Universe.
Abstract: There is increasing evidence to suggest that there are many more galaxies than we would have expected from extrapolation of observations of the nearby Universe. Deep observations of the distant Universe reveal a much larger number density of galaxies than is observed locally. The spectra of distant quasars show far too many absorption-line features to be accounted for by the local galaxy population. Big Bang nucleosynthesis predicts a factor of 5–10 times more baryonic matter in the Universe than is seen in galaxies. The brightness of the Earthly night sky (about 23 blue magnitudes aresec-2 (Bμ)at a dark site) sets quite stringent limits on what we can hope to detect as Earth bound observers. Is our perception of the Universe highly biased by the position from which we observe it? Or more explicitly for this paper, how many galaxies may we be missing when we survey the sky?
TL;DR: In this paper, the present temperature of the cosmic microwave background radiation, the specific entropy in the matter era and the model properties of the expansive nondecelerative universe are used to determine the present parameters of our universe with deviations smaller than 2.2%.
Abstract: (a) Hubble's discovery of the expansion of the Universe makes it possible to choose unambiguously from the models described by Friedmann's equations of universe dynamics. (b) From the present temperature of the cosmic microwave background radiation, the specific entropy in the matter era and the model properties of the expansive nondecelerative universe, we can determine the present parameters of our Universe with deviations smaller than 2.2%.
TL;DR: In this article, it is shown that at the transition epoch t = 10−23 sec the creation phenomenon stops and the usual cosmology of the radiation era follows with Pascal's equation of state.
Abstract: This article deals with the particle and entropy productions in the early universe, which is regarded as a thermodynamically open system in the sense of Prigogine, by incorporating the epoch dependence of elementary particle masses. The epoch dependence of particle masses for some of the Robertson-Walker (RW) universes appears as a consequence of previous considerations of the hadronic matter extension in the inner space-time regarded as anisotropic and Finslerian in character. The nature of the evolution of the early universe has been discussed in the framework of the modified thermodynamic energy conservation law and the new mass formula apart from the other Einstein equation. The trivial solution of these equations is the usual inflationary stage of the early universe, whereas the matter-dominated RW universe appears as the nontrivial solution. It is shown that at the “transition epoch”t=10−23 sec the creation phenomenon stops and the usual cosmology of the radiation era follows with Pascal's equation of state. This model can also account for the observed specific entropy per baryon of the present universe and the generation of the large value ofK−1, whereK=Gmp2/ħc,mp being the mass of the proton.
TL;DR: The mass difference between leptoquarks and antileptacons appearing due to T -symmetry violation at the early stages of the expansion of the universe is evaluated in this paper.
TL;DR: In this paper, the origin of seed perturbations in the universe is studied within the framework of a specific minisuperspace model and it is shown that the creation of the universe as a result of a quantum transition from a flat empty spacetime would lead to a flat FLRW (Friedmann-Lemaitre-Robertson-Walker) universe with weak inhomogeneous perturbation at large wavelengths.
Abstract: The origin of seed perturbations in the universe is studied within the framework of a specific minisuperspace model. It is shown that the creation of the universe as a result of a quantum transition from a flat empty spacetime would lead to a flat FLRW (Friedmann-Lemaitre-Robertson-Walker) universe with weak inhomogeneous perturbations at large wavelengths. The power spectrum of these perturbations is found to be scale invariant at horizon crossing (i.e., the Harrison-Zel'dovich spectrum)
TL;DR: In this article, the authors investigate the thermodynamic and hydrodynamical effects on the structure formation on scales of 20 h − 1 Mpc in the Einstein de-Sitter universe by three-dimensional numerical simulation.
Abstract: We investigate the thermodynamical and hydrodynamical effects on the structure formation on scales of 20 h −1 Mpc in the Einstein de-Sitter universe by three-dimensional numerical simulation. Calculations involve cosmological expansion, self-gravity, hydrodynamics, and cooling processes with 100 × 100 × 100 mesh cells and the same number of CDM particles. Galactic bursts out of young galaxies as a heat input are parametrically taken into account. We find that the thermodynamics of the intergalactic medium plays an important role in formation of galaxies, the rate of galaxy formation depends on the amount of the energy burst from galaxies, and that the critical energy scale to affect the structure of the universe is 10 57-59 erg
TL;DR: In this paper, the authors investigated the behavior of small inhomogeneous perturbations around a Friedman-Robertson-Walker model and showed that these perturbation cannot be time symmetric if they were small at the Big Bang.
Abstract: We investigate the time neutral formulation of quantum cosmology of Gell-Mann and Hartle. In particular we study the proposal discussed by them that our Universe corresponds to the time symmetric decoherence functional with initial and final density matrix of low entropy. We show that our Universe does not correspond to this proposal by investigating the behaviour of small inhomogeneous perturbations around a Friedman-Robertson-Walker model. These perturbations cannot be time symmetric if they were small at the Big Bang.
TL;DR: In this article, a path integral approach for the case of conformal matter coupled to a Friedman-Robertson-Walker space time is presented, and a relation is found between the cosmological constant, the number of matter fields and the self coupling of matter responsable for its instability.
TL;DR: In this article, the authors propose an alternative approach to the problem of initial conditions for large-scale structure formation in the early universe by considering a nonzero bulk viscosity with energy density fluctuations.
TL;DR: Numerical solutions are obtained which show that the Universe expands exponentially and the texture field decays in a finite time; this corresponds to a period of inflation followed naturally by a Friedmann expansion.
Abstract: We present a cosmological model with a global homogeneous texture and inflation, but without an initial singularity. The Universe starts from an equilibrium configuration in a symmetric vacuum; the dynamic stability of this configuration is studied. We obtain numerical solutions which show that the Universe expands exponentially and the texture field decays in a finite time; this corresponds to a period of inflation followed naturally by a Friedmann expansion.
TL;DR: In this paper, a simple solution was derived from the momentum conservation under the effect of gravity and energy input for the explosion without a continuous energy-input, partition of energy between kinetic and gravitational energies is discussed.
Abstract: Shell motion in the expanding universe is investigated using a simple solution, which is derived from the momentum conservation under the effect of gravity and energy-input. A similarity solution is given for the constant energy-input case. For the explosion without a continuous energy-input, partition of energy between kinetic and gravitational energies is discussed. The blast wave expansion due to an activity of galactic objects in the early universe is discussed
TL;DR: In this paper, the most general semiclassical solution describing inhomogeneous universe is discussed, and all the big bang type universe is shown to end in a flat universe with a universally created matter, irrespective of arty irregularities initially present.
Abstract: Two dimensional dilaton gravity theories provide a class of cosmological toy models in which the semiclassical quantum correction is analytically solvable. The most general semiclassical solution describing inhomogeneous universe is discussed, and all the big bang type universe is shown to end in a flat universe with a universally created matter, irrespective of arty irregularities initially present. It is also pointed out that the same universal behavior towards the final stage of universe remains valid to the leading 'Ii order in the nonintegrable model.
01 Apr 1993
TL;DR: In this article, the effects of neutrinos on primordial nucleosynthesis and on the dynamics and large scale structure of the universe were discussed. And the complementary nature of the Astro-Particle Physics Connection was emphasized with particular attention paid to the 17 keV neutrino, light neutrines as hot dark matter and constraints on the mass and lifetime of the tau-neutrino.
Abstract: Although very weakly interacting, neutrinos are produced copiously in the early universe and may play a crucial role in establishing the contents and structure of the universe and its subsequent evolution. After reviewing the physics which influences the production and survival of neutrinos--massive as well as massless--in the early universe, I will outline their effects on primordial nucleosynthesis and on the dynamics and large scale structure of the universe. The complementary nature of the Astro-Particle Physics Connection will be emphasized with particular attention paid to the “17 keV neutrino”, light neutrinos as hot dark matter and constraints on the mass and lifetime of the tau-neutrino.