Results 61 to 70 of about 17,519 (197)
In What Sense Is the Early Universe Fine-Tuned? [PDF]
, 2014 It is commonplace in discussions of modern cosmology to assert that the early universe began in a special state. Conventionally, cosmologists characterize this fine-tuning in terms of the horizon and flatness problems.
Carroll, Sean M.
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Cosmological models with flat spatial geometry [PDF]
Classical and Quantum Gravity, 2000 12 pages, LaTeX2e, IOP style.
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Scale Invariant Density Perturbations from Cyclic Cosmology
, 2015 It is shown how quantum fluctuations of the radiation during the contraction era of a CBE (Comes Back Empty) cyclic cosmology can provide density fluctuations which re-enter the horizon during the subsequent expansion era and at lowest order are scale ...
Frampton, Paul Howard
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Vector field mediated models of dynamical light velocity
, 2000 A vector-tensor theory of gravity that was introduced in an earlier publication is analyzed in detail and its consequences for early universe cosmology are examined.
Albrecht A. +4 more
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The Basics of Flat Space Cosmology
International Journal of Astronomy and Astrophysics, 2015 We present a new model of cosmology which appears to show great promise. Our flat space cosmology model, using only four basic and reasonable assumptions, derives highly accurate Hubble parameter H0, Hubble radius R0 and total mass M0 values for our observable universe.
Eugene Terry Tatum +2 more
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Implications of Cosmic Repulsion for Gravitational Theory
, 1998 In this paper we present a general, model independent analysis of a recently detected apparent cosmic repulsion, and discuss its potential implications for gravitational theory. In particular, we show that a negatively spatially curved universe acts like
A. Edery +26 more
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Thermodynamic solution of the homogeneity, isotropy and flatness puzzles (and a clue to the cosmological constant) [PDF]
, 2022 Latham Boyle, Neil Turok
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Higher Spin Resolution of a Toy Big Bang
, 2014 Diffeomorphisms preserve spacetime singularities, whereas higher spin symmetries need not. Since three dimensional de Sitter space has quotients that have big-bang/big-crunch singularities and since dS_3-gravity can be written as an SL(2,C) Chern-Simons ...
Krishnan, Chethan, Roy, Shubho
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Why Flat Space Cosmology Is Superior to Standard Inflationary Cosmology
Journal of Modern Physics, 2018 Following recent Cosmic Microwave Background (CMB) observations of global spatial flatness, only two types of viable cosmological models remain: inflationary models which almost instantaneously attain cosmic flatness following the Big Bang; and non-inflationary models which are spatially flat from inception.
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The flatness problem and $\Lambda$
, 2005 By way of a complete integration of the Friedmann equations, in terms of observables, it is shown that for the cosmological constant $\Lambda > 0$ there exist non-flat FLRW models for which the total density parameter $\Omega$ remains $\sim 1$ throughout
A. G. Riess +7 more
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