126 research outputs found
A new perspective on steady-state cosmology: from Einstein to Hoyle
We recently reported the discovery of an unpublished manuscript by Albert
Einstein in which he attempted a 'steady-state' model of the universe, i.e., a
cosmic model in which the expanding universe remains essentially unchanged due
to a continuous formation of matter from empty space. The manuscript was
apparently written in early 1931, many years before the steady-state models of
Fred Hoyle, Hermann Bondi and Thomas Gold. We compare Einstein's steady-state
cosmology with that of Hoyle, Bondi and Gold and consider the reasons Einstein
abandoned his model. The relevance of steady-state models for today's cosmology
is briefly reviewed.Comment: To be published in the 'Proceedings of the 2014 Institute of Physics
International Conference on the History of Physics', Cambridge University
Press. arXiv admin note: substantial text overlap with arXiv:1504.02873,
arXiv:1402.013
Cronyism and Capital Controls: Evidence from Malaysia
The initial impact of the Asian financial crisis in Malaysia reduced the expected value of government subsidies to politically favored firms. Of the estimated 5 billion gain in market value for Mahathir-connected firms during September 1998, approximately 32% was due to the increase in the value of their connections. The evidence suggests Malaysian capital controls provided a screen behind which favored firms could be supported.
Propping and Tunneling
In countries with weak legal systems, there is a great deal of tunnelling by the entrepreneurs who control publicly traded firms. However, under some conditions entrepreneurs prop up their firms, i.e., they use their private funds to benefit minority shareholders. We provide evidence and a model that explains propping. In particular, we suggest that issuing debt can credibly commit an entrepreneur to propping, even though creditors can never take possession of any underlying collateral. This helps to explain why emerging markets with weak institutions sometimes grow rapidly and why they are also subject to frequent economic and financial crises.
Determinants of Vertical Integration: Finance, Contracts, and Regulation
We study the determinants of vertical integration in a new dataset of over 750,000 firms from 93 countries. Existing evidence suggests the presence of large cross-country differences in the organization of firms, which may be related to differences in financial development, contracting costs or regulation. We find cross-country correlations between vertical integration on the one hand and financial development, contracting costs, and entry barriers on the other that are consistent with these "priors". Nevertheless, we also show that these correlations are almost entirely driven by industrial composition; countries with more limited financial development, higher contracting costs or greater entry barriers are concentrated in industries with a high propensity for vertical integration. Once we control for differences in industrial composition, none of these factors are correlated with average vertical integration. However, we also find a relatively robust differential effect of financial development across industries; countries with less-developed financial markets are significantly more integrated in industries that are more human capital or technology intensive.
One Hundred Years of the Cosmological Constant: from 'Superfluous Stunt' to Dark Energy
We present a centennial review of the history of the term known as the
cosmological constant. First introduced to the general theory of relativity by
Einstein in 1917 in order to describe a universe that was assumed to be static,
the term fell from favour in the wake of the discovery of the expanding
universe, only to make a dramatic return in recent times. We consider
historical and philosophical aspects of the cosmological constant over four
main epochs: (i) the use of the term in static cosmologies (both Newtonian and
relativistic); (ii) the marginalization of the term following the discovery of
cosmic expansion; (iii) the use of the term to address specific cosmic puzzles
such as the timespan of expansion, the formation of galaxies and the redshifts
of the quasars; (iv) the re-emergence of the term in today's Lamda-CDM
cosmology. We find that the cosmological constant was never truly banished from
theoretical models of the universe, but was sidelined by astronomers for
reasons of convenience. We also find that the return of the term to the
forefront of modern cosmology did not occur as an abrupt paradigm shift due to
one particular set of observations, but as the result of a number of empirical
advances such as the measurement of present cosmic expansion using the Hubble
Space Telescope, the measurement of past expansion using type SN 1a supernovae
as standard candles, and the measurement of perturbations in the cosmic
microwave background by balloon and satellite. We give a brief overview of
contemporary interpretations of the physics underlying the cosmic constant and
conclude with a synopsis of the famous cosmological constant problem.Comment: 60 pages, 6 figures. Some corrections, additions and extra
references. Accepted for publication the European Physical Journal (H
Einstein's cosmology review of 1933: a new perspective on the Einstein-de Sitter model of the cosmos
We present a first English translation and analysis of a little-known review
of relativistic cosmology written by Albert Einstein in late 1932. The article,
which was published in 1933 in a book of Einstein papers translated into
French, contains a substantial review of static and dynamic relativistic models
of the cosmos, culminating in a discussion of the Einstein-de Sitter model. The
article offers a valuable contemporaneous insight into Einstein's cosmology in
the 1930s and confirms that his interest lay in the development of the simplest
model of the cosmos that could account for observation, rather than an
exploration of all possible cosmic models. The article also confirms that
Einstein did not believe that simplistic relativistic models could give an
accurate description of the early universe.Comment: Accepted for publication in the European Physical Journal (H).
Includes an English translation of a little-known review of cosmology written
by Albert Einstein in 1933. 20 pages, 4 figure
Historical and philosophical reflections on the Einstein-de Sitter model
We present some historical and philosophical reflections on the paper "On the
Relation Between the Expansion and the Mean Density of the Universe", published
by Albert Einstein and Willem de Sitter in 1932. In this famous work, Einstein
and de Sitter considered a relativistic model of the expanding universe with
both the cosmological constant and the curvature of space set to zero. Although
the Einstein-deSitter model went on to serve as a standard model in 'big bang'
cosmology for many years, we note that the authors do not explicitly consider
the evolution of the cosmos in the paper. Indeed, the mathematics of the
article are quite puzzling to modern eyes. We consider claims that the paper
was neither original nor important; we find that, by providing the first
specific analysis of the case of a dynamic cosmology without a cosmological
constant or spatial curvature, the authors delivered a unique, simple model
with a straightforward relation between cosmic expansion and the mean density
of matter that set an important benchmark for both theorists and observers. We
consider some philosophical aspects of the model and provide a brief review of
its use as a prototype 'big bang' model over much of the 20th century.Comment: Some revisions and corrections to original MS. Accepted for
publication in the European Physical Journal (H
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