Primeval symmetries

A detailed examination of the Killing equations in Robertson-Walker coordinates shows how the addition of matter and/or radiation to a de Sitter Universe breaks the symmetry generated by four of its Killing fields. The product U = (a^2)(dH/dt) of the squared scale parameter by the time-derivative of the Hubble function encapsulates the relationship between the two cases: the symmetry is maximal when U is a constant, and reduces to the six-parameter symmetry of a generic Friedmann-Robertson-Walker model when it is not. As the fields physical interpretation is not clear in these coordinates, comparison is made with the Killing fields in static coordinates, whose interpretation is made clearer by their direct relationship to the Poincare group generators via Wigner-Inonu contractions.Comment: 16 pages, 2 tables; published versio

Externalities and Compensation: Primeval Games and Solutions

The classical literature (Pigou (1920), Coase (1960), Arrow (1970)) and the relatively recent studies (cf.Varian (1994)) associate the externality problem with efficiency.This paper focuses explicitly on the compensation problem in the context of externalities.To capture the features of inter-individual externalities, this paper constructs a new game-theoretic framework: primeval games.These games are used to design normative compensation rules for the underlying compensation problems: the marginalistic rule, the concession rule, and the primeval rule.Characterizations of the marginalistic rule and the concession rule are provided and specific properties of the primeval rule are studied.externality;compensation;primeval games;marginalistic rule;concession rule;primeval rule

A Non-cooperative Approach to the Compensation Rules for Primeval Games

AMS Classifications: 91A06; 91A10; 91A12externality;compensation;primeval games;marginalistic rule;concession rule;primeval rule;bidding mechanism;implementation

Searches For Primeval Galaxies

A primeval galaxy represents the earliest stages of a galaxy's life and as such provides clues to the early history of the Universe and the evolution of stars and galaxies. Over the last 20 years astronomers have been engaged in the quest to detect the faint signals from these objects, believed to lie at a distance comparable with the size of the Universe. A wide variety of observational techniques have been employed in this search, with astronomers eagerly awaiting each new generation of astronomical telescope or detector in the hope of finally solving the mystery to the origin of galaxies -- or at least placing new and interesting constraints. Until recently, primeval galaxies have eluded detection in these searches, however experiments over the last couple of years which use either 10m-class optical telescopes or state-of-the-art submillimetre array detectors, may hold the clue to the origin of structure as they have finally uncovered what appears to be a widespread population of young galaxies.Comment: 17 pages, 5 figures. Paper to be published in Contemporary Physic

Externalities and compensation: Primeval games and solutions

The classical literature [Pigou, A.C., 1920. The Economics of Welfare. Macmillan, London; Coase, R.H., 1960. The problem of social cost. Journal of Law and Economics 3, 1-44; Arrow, K., 1970. The organization of economic activity: issues pertinent to the choice of market versus non-market allocation. In: Haveman, R.H., Margolis, J. (Eds.), Public Expenditures and Policy Analysis. Markham, Chicago, pp. 59-73] and the relatively recent studies [cf. Varian, H.R., 1994. A solution to the problem of externalities when agents are well-informed. American Economic Review 84, 1278-1293] associate the externality problem with efficiency. This paper focuses explicitly on the compensation problem in the context of externalities. To capture the features of inter-individual externalities, this paper constructs a new game-theoretic framework: primeval games. These games are used to design normative compensation rules for the underlying compensation problems: the marginalistic rule, the concession rule, and the primeval rule. Characterizations of the marginalistic rule and the concession rule are provided and specific properties of the primeval rule are studied. (C) 2007 Elsevier B.V. All rights reserved

A Primeval Magellanic Stream and Others

The Magellanic Stream might have grown out of tidal interactions at high redshift, when the young galaxies were close together, rather than from later interactions among the Magellanic Clouds and Milky Way. This is illustrated in solutions for the orbits of Local Group galaxies under the cosmological condition of growing peculiar velocities at high redshift. Massless test particles initially near and moving with the Large Magellanic Cloud in these solutions end up with distributions in angular position and redshift similar to the Magellanic Stream, though with the usual overly prominent leading component that the Milky Way corona might have suppressed. Another possible example of the effect of conditions at high redshift is a model primeval stream around the Local Group galaxy NGC 6822. Depending on the solution for Local Group dynamics this primeval stream can end up with position angle similar to the HI around this galaxy, and a redshift gradient in the observed direction. The gradient is much smaller than observed, but might have been increased by dissipative contraction. Presented also is an even more speculative illustration of the possible effect of initial conditions, primeval stellar streams around M31.Comment: 23 pages, 7 figure

Constraints on primordial black holes and primeval density perturbations from the epoch of reionization

We investigate the constraint on the abundance of primordial black holes (PBHs) and the spectral index $n$ of primeval density perturbations given by the ionizing photon background at the epoch of reionization. Within the standard inflationary cosmogony, we show that the spectral index $n$ of the power-law power spectrum of primeval density perturbations should be $n<$1.27. Since the universe is still optical thick at the reionization redshift $z\sim 6$ - 8, this constraint is independent of the unknown parameter of reheating temperature of the inflation. The ionizing photon background from the PBHs can be well approximated by a power law spectrum $J(\nu)\propto{\nu}^3$, which is greatly different from those given by models of massive stars and quasars.Comment: 4 pages, 3 eps figues, to be published in ApJ Letter