Showing papers on "Cosmology published in 1982"
TL;DR: A new inflationary universe scenario is suggested in this paper, which is free of the shortcomings of the previous one and provides a possible solution of the horizon, flatness, homogeneity and isotropy problems in cosmology.
5,291 citations
TL;DR: In this article, the authors introduce a small Z(N) breaking interaction into axion models without upsetting the Peccei-Quinn mechanism, which leads to galaxy formation.
Abstract: Axion models have a spontaneously broken Z{A) symmetry. The resulting discretely degenerate vacua and domain-wall solitons are incompatible with the standard cosmology. It is possible, however, to introduce a small Z(N) breaking interaction into axion models without upsetting the Peccei-Quinn mechanism. In that case the domain walls disappear a certain time after their formation in the early universe. Their. presence for a limited time period might lead to galaxy formation.
556 citations
TL;DR: In this paper, position angles and polarization of high luminosity classical-double radio sources are studied and it is shown that the difference between position angles of elongation and of polarization are highly organized, being generally positive in one half of the sky and negative in the other.
Abstract: From the study of the position angles and polarization of high luminosity classical-double radio sources, it appears that the difference between the position angles of elongation and of polarization are highly organized, being generally positive in one half of the sky and negative in the other. The effect was first noticed amongst a sample of 94 3CR sources and later confirmed in three independent samples. Such a phenomenon can only have a physical explanation on a cosmic scale; an attractive theory is that it demonstrates the existence of a universal vorticity, that is, that the Universe is rotating with an angular velocity ∼10−13 rad yr−1. This would have drastic cosmological consequences, since it would violate Mach's principle1,2 and the widely held assumption of large-scale isotropy.
213 citations
TL;DR: In this article, a mechanism for the spontaneous creation of density perturbations during the transition in the early Universe from unconfined quark matter to hadronic matter is presented.
Abstract: A long-standing problem in cosmology has been to understand the origins of density inhomogeneities in the Universe. Calculations involving inhomogeneities have for the most part required the assumption of some initial spectrum of perturbations, which is inserted ‘by hand’. We present here a mechanism for the spontaneous creation of density perturbations during the transition in the early Universe from unconfined quark matter to hadronic matter. The subsequent evolution of these perturbations remains a problem for further study.
201 citations
TL;DR: In this article, the authors estimate the abundance of primordial black holes and their effects on cosmology and show that they play several important roles in the subsequent evolution of the universe and that the observational information of the present universe, conversely, yields constraints on the phenomenological parameters in grand unified theories.
Abstract: One important prediction of a cosmological model based on grand unified theories is the production of primordial black holes and wormholes through a first· order phase transition. In this paper we estimate the abundance of these holes and their effects on cosmology. We show that they play several important roles in the subsequent evolution of the universe and that the observational information of the present universe, conversely, yields constraints on the phenomenological parameters in grand unified theories. Especially we find that both the thermal and quantum nucleations of vacuum bubbles are the necessary ingredients in construct· ing a cosmological model consistent with the present observations.
172 citations
TL;DR: In this paper, the density perturbation spectrum of gravitinos is shown to be relatively flat between galactic and cluster scales, unlike the massive neutrino case, and it is shown that gravitines form the dark matter, initial adiabatic fluctuations lead to a hierarchical picture of clustering.
Abstract: If gravitinos of mass 1 keV (or similar particles) dominate the mass of the universe, a critical scale of galactic size arises due to their collisionless phase mixing. It is shown that density perturbation spectrum of gravitinos is relatively flat between galactic and cluster scales, unlike the massive neutrino case. If gravitinos form the dark matter, initial adiabatic fluctuations lead to a hierarchical picture of clustering. Galaxies form first, but dissipation is necessary for their survival.
141 citations
135 citations
TL;DR: In this paper, it was shown that the gravitino dominated universe can produce galaxies by gravitational instability while avoiding several observational difficulties associated with the neutrino-dominated universe, and it was also shown that in a baryon dominated universe there is no scale length corresponding to the masses of galaxies.
Abstract: In a baryon dominated universe, there is no scale length corresponding to the masses of galaxies. If neutrinos with mass 50 eV without exceeding the observational mass density limit. A candidate particle is the gravitino, the spin 3/2 supersymmetric partner of the graviton, which has been shown1 to have a mass ≲1 keV if stable2. The Jeans mass for a 1-keV noninteracting particle is ∼1012 M⊙, about the mass of a typical spiral galaxy including the nonluminous halo. We suggest here that the gravitino dominated universe can produce galaxies by gravitational instability while avoiding several observational difficulties associated with the neutrino dominated universe.
124 citations
TL;DR: In this article, the gravitational lens effects of a cosmological density of compact objects with masses in the range 0.01 to 0.1 were investigated. But the results were limited to the case where the density of the objects was unknown.
Abstract: The gravitational lens effects of a cosmological density of compact objects with masses in the range 0.01
78 citations
TL;DR: In this article, it is shown that the lifetime of a metastable vacuum can be very long, even when compared with the age of the universe, and the energy densities available in present laboratory or astrophysical environments are much less than the barriers which exist in field space between the different local minima, and so we have no direct sensitivity to the presence of a possibly lower vacuum state.
Abstract: In spontaneously broken gauge theories of particle interactions there are sometimes several local minima of the effective potential. Any of these minima can serve as a vacuum in the sense that we can expand the fields around their values at the minimum, interpret the quantized fluctuations around the minimum as particles, and compare the properties of these particles with experiment. One might think that only the state with absolutely minimum energy could be what we ordinarily call our vacuum, as the other local minima will inevitably decay into this lowest one. However, this is not necessarily the case, because it is possible for the lifetime of a metastable vacuum to be very long, even when compared with the age of the Universe. Furthermore, the energy densities available in present laboratory or astrophysical environments are much less than the barriers which exist in field space between the different local minima, and so we have no direct sensitivity to the presence of a possibly lower vacuum state. (A possible exception to this are magnetic monopoles which do probe the large field region.) If it is not the absolute minimization of the effective potential, what does determine the present vacuum state of the Universe? We argue here that it is determined cosmologically by the dynamical evolution of the Universe from the hot, dense phase which existed shortly after the big bang to the present1,2.
67 citations
TL;DR: In this article, the experimental information on p 4 He annihilation may impose limits on the possible amount of anti-matter in the early universe and other important cosmological topics, predicted by some variants of GUT cosmology.
TL;DR: An exact formalism for describing cosmological models with strong, long wavelength gravitational waves of general polarization, propagating over backgrounds corresponding to Bianchi types I through VII was developed in this article.
Abstract: An exact formalism is developed for describing cosmological models with strong, long wavelength gravitational waves of general polarization, propagating over backgrounds corresponding to Bianchi types I through VII. A new metric which exhibits the appropriate symmetries of two equivalent independent polarizations of gravitational waves is introduced and discussed. The formalism is applied to an empty type I cosmology, and it is shown how the original z-dependent chaotic singularity structure transforms itself into gravitational radiation propagating along the z-axis in a Bianchi I background.
TL;DR: In this article, it was shown that even if the intrinsic probability of a lensing event is very low, the effect becomes important if the background density of faint sources rises sufficiently quickly.
Abstract: Empirical descriptions of cosmological evolution rely on an assumed relation between luminosity distance and redshift in order to derive the luminosity function and its epoch dependence. This relation is usually taken to be that of an idealised Friedmann cosmology, despite the obvious abundance of small-scale structure in the Universe. However, the assumption that the probability of a lensing event is negligible is now made less tenable with the discovery of the double and triple QSO’s, both of which appear to have been magnified by factors of 10–15. With at least two events of this amplification in 1500 known quasars, it may be that a large fraction of observed QSO’s have been magnified by significant amounts. Turner (1980) suggests that all evolutionary statistics (e.g. V/Vmax) may thus be misleading, although he considers only an illustrative model of the effect. The problem is that, even if the intrinsic probability of a lensing event is very low, the effect becomes important if the background density of faint sources rises sufficiently quickly. We must therefore calculate not only the intrinsic probability of a given amplification, but incorporate this with the luminosity function to see if lensing could be made dominant by selection effects.
TL;DR: In this article, the existence of antimatter in the universe and its possible astrophysical observational effects are discussed. And the authors show that unique information on the possible presence of the antimatter at the stage of radiation dominance in the Universe (t <10/sup 18/ s) may be obtained from the study of anti p/sup 4/He annihilation.
Abstract: The review is organized as follows. We start with a brief description of the modern views on the evolution of the Universe. After that we discuss the problem of the existence of antimatter in the Universe and its possible astrophysical observational effects. We show that unique information on the possible presence of antimatter at the stage of radiation dominance in the Universe (t<10/sup 18/ s) may be obtained from the study of anti p/sup 4/He annihilation. We consider the physics of primordial black holes (theor formation and evaporation), the formation and annihilation of antimatter domains, the relationship between these sources of antimatter and the phase transitions in the early Universe as well as heavy metastable particles predicted by GUTs. The observed abundances of light elements and their possible changes due to annihilation are discussed. In conclusion the necessary measurements and the restrictions on the parameters of GUT models which may be obtained from these measurements are considered.
TL;DR: The nuclear species of cosmological interest are 1H, D, 3He, 4He and 7Li (Schramm & Wagoner I977) and in this paper the authors try to explain what we know about their present abundances in the interstellar medium and what estimates of their primordial abundances we can make when the effects of nuclear synthesis and destruction in stars are allowed for.
Abstract: The nuclear species of cosmological interest are 1H, D, 3He, 4He and 7Li (Schramm & Wagoner I977) and m this paper I shall try to explain what we know about their present abundances in the interstellar medium and what estimates of their primordial abundances we can make when the effects of nuclear synthesis and destruction in stars are allowed for. The interpretation of the resulting constraints on Big-Bang cosmology will largely be left to other papers in this symposium, apart from a small final excursion designed to discuss the mutual consistency of the constraints imposed by the various abundances within the framework of conventional Big-Bang models (Yang et al . 1979; Olive et al. 1981).
TL;DR: In this article, the cosmic connections between physics on the very largest and very smallest scales are reviewed with an emphasis on the symbiotic relation between elementary particle physics and cosmology, and various cosmological and astrophysical constraints on models of particle physics are outlined.
Abstract: The cosmic connections between physics on the very largest and very smallest scales are reviewed with an emphasis on the symbiotic relation between elementary particle physics and cosmology. After a review of the early Universe as a cosmic accelerator, various cosmological and astrophysical constraints on models of particle physics are outlined. To illustrate this approach to particle physics via cosmology, reference is made to several areas of current research: baryon non-conservation and baryon asymmetry; free quarks, heavy hadrons and other exotic relics; primordial nucleosynthesis and neutrino masses. In the last few years we have witnessed the birth and growth to healthy adolescence of a new collaboration between astrophysicists and particle physicists. The most notable success of this cooperative effort has been to provide the framework for understanding, within the context of GUTs and the hot big-bang cosmology, the universal baryon asymmetry. The most exciting new predictions this effort has spawned are that exotic relics may exist in detectable abundances. In particular, we may live in a neutrino-dominated Universe. In the next few years, accummulating laboratory data (for example proton decay, neutrino masses and oscillations) coupled with theoritical work in particle physics and cosmology will ensure the growth to maturity of this joint effort.
TL;DR: In this article, it is argued that the false vacuumis is destabilized at T ∼ 109 GeV for SU(5) phase transition with Coleman-Weinberg type of symmetry breaking.
TL;DR: In this article, the gross parameters characterizing the Universe such as the overall size and mass can be arrived at from microphysical considerations involving the fundamental interactions of elementary particle physics, and interesting relations for the Hubble radius and closure density are obtained in terms of the coupling constants underlying these interactions.
Abstract: It is pointed out that the gross parameters characterizing the Universe such as the overall size and mass can be arrived at from microphysical considerations involving the fundamental interactions of elementary particle physics. Interesting relations for the Hubble radius and closure density are obtained in terms of the coupling constants underlying these interactions.
TL;DR: In this paper, the existence of double layers in magnetized plasmas and in the low magnetosphere, and energy transfer by electric current in the auroral circuit are discussed.
Abstract: New discoveries in cosmic plasma physics are described, and their applications to solar, interstellar, galactic, and cosmological problems are discussed The new discoveries include the existence of double layers in magnetized plasmas and in the low magnetosphere, and energy transfer by electric current in the auroral circuit It is argued that solar flares and the solar wind-magnetosphere interaction should not be interpreted in terms of magnetic merging theories, and that electric current needs to be explicitly taken account of in understanding these phenomena The filamentary structure of cosmic plasmas may be caused by electric currents in space, and the pinch effect may have a central role to play in the evolutionary history of interstellar clouds, stars, and solar systems Space may have a cellular structure, with the cell walls formed by thin electric current layers Annihilation may be the source of energy for quasars and the Hubble expansion, and the big bang cosmology may well be wrong
TL;DR: In this paper, it was shown that a cold expanding universe naturally produces stars at high redshift, and these stars must also be held accountable for the production of the microwave background, galaxies, and, probably, helium.
Abstract: This paper shows that a cold expanding universe naturally produces stars at high redshift. A homogeneous universe composed of low-entropy matter (S or approx. =2 M/sub sun/, none would be burning now, but their remnants may form the darkmore » matter in galactic halos and clusters. These stars must also be held accountable for the production of the microwave background, galaxies, and, probably, helium. The model makes simple predictions about the expected large-scale anisotropy in the microwave background which differ from standard theories postulating fluctuations in the initial state and/or a primordial origin for the entropy. Other less direct tests are also proposed.« less
01 Jul 1982
TL;DR: In this article, the authors consider the early universe and show that existing observational constraints on the PBH spectrum may be compatible with small-scale inhomogeneity in early universe, and they place limits on the fraction of matter incorporated in primordial black holes.
Abstract: When allowance is made for possible dustlike (p = 0) eras in the early universe, the constraints on the fraction of matter incorporated in primordial black holes become less stringent. Corresponding limits are placed on the parameters of unified gauge theories. Existing observational constraints on the PBH spectrum may be compatible with small-scale inhomogeneity in the early universe.
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01 Jan 1982
TL;DR: In this paper, the evolution of inhomogeneous density perturbations in a model of the very early universe that is dominated for a time by a constant energy density of a false quantum-mechanical vacuum is analyzed.
Abstract: The evolution of inhomogeneous density perturbations in a model of the very early universe that is dominated for a time by a constant energy density of a false quantum-mechanical vacuum is analyzed. During this period, the universe inflates exponentially and supercools exponentially, until a phase transition back to the true vacuum reheats the matter and radiation. Focus is on the physically measurable, coordinate-independent modes of inhomogeneous perturbations of this model and it is found that all modes either are constant or are exponentially damped during the inflationary era.
TL;DR: In this paper, the effect of the expansion of the universe upon the rate of decay of a massive scalar particle is investigated. But in general this process is not CPT invariant, and the application of the results to the early universe is discussed.