Modifications of Einstein's Theory of Gravity at Large Distances PDF Download

Author: Eleftherios Papantonopoulos
Publisher: Springer
ISBN: 331910070X
Category : Science
Languages : en
Pages : 426

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Book Description
In the last few years modified gravity theories have been proposed as extensions of Einstein's theory of gravity. Their main motivation is to explain the latest cosmological and astrophysical data on dark energy and dark matter. The study of general relativity at small scales has already produced important results (cf e.g. LNP 863 Quantum Gravity and Quantum Cosmology) while its study at large scales is challenging because recent and upcoming observational results will provide important information on the validity of these modified theories. In this volume, various aspects of modified gravity at large scales will be discussed: high-curvature gravity theories; general scalar-tensor theories; Galileon theories and their cosmological applications; F(R) gravity theories; massive, new massive and topologically massive gravity; Chern-Simons modifications of general relativity (including holographic variants) and higher-spin gravity theories, to name but a few of the most important recent developments. Edited and authored by leading researchers in the field and cast into the form of a multi-author textbook at postgraduate level, this volume will be of benefit to all postgraduate students and newcomers from neighboring disciplines wishing to find a comprehensive guide for their future research.

Author: Lorenzo Iorio
Publisher: MDPI
ISBN: 303842482X
Category : Electronic book
Languages : en
Pages : 469

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Book Description
This book is a printed edition of the Special Issue "100 Years of Chronogeometrodynamics: the Status of the Einstein's Theory of Gravitation in Its Centennial Year" that was published in Universe

Author: John W. Moffat
Publisher: Harper Collins
ISBN: 0061982180
Category : Technology & Engineering
Languages : en
Pages : 506

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Book Description
Einstein's gravity theory—his general theory of relativity—has served as the basis for a series of astonishing cosmological discoveries. But what if, nonetheless, Einstein got it wrong? Since the 1930s, physicists have noticed an alarming discrepancy between the universe as we see it and the universe that Einstein's theory of relativity predicts. There just doesn't seem to be enough stuff out there for everything to hang together. Galaxies spin so fast that, based on the amount of visible matter in them, they ought to be flung to pieces, the same way a spinning yo-yo can break its string. Cosmologists tried to solve the problem by positing dark matter—a mysterious, invisible substance that surrounds galaxies, holding the visible matter in place—and particle physicists, attempting to identify the nature of the stuff, have undertaken a slew of experiments to detect it. So far, none have. Now, John W. Moffat, a physicist at the Perimeter Institute for Theoretical Physics in Waterloo, Canada, offers a different solution to the problem. The cap­stone to a storybook career—one that began with a correspondence with Einstein and a conversation with Niels Bohr—Moffat's modified gravity theory, or MOG, can model the movements of the universe without recourse to dark matter, and his work chal­lenging the constancy of the speed of light raises a stark challenge to the usual models of the first half-million years of the universe's existence. This bold new work, presenting the entirety of Moffat's hypothesis to a general readership for the first time, promises to overturn everything we thought we knew about the origins and evolution of the universe.

Author: Cesar Augusto Zen Vasconcellos
Publisher: World Scientific
ISBN: 9813277351
Category : Science
Languages : en
Pages : 299

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Book Description
'The book concentrates attention on extended alternative theories of gravity and on the best astrophysical laboratories to probe the strong gravity-field regime: black holes, pulsars and neutron stars … Readers will likely share the satisfaction the editor and contributors say they experienced as they organized the book.'SirReadaLotFor more than a century, our understanding of gravitational physics was based on Albert Einstein's theory of General Relativity, which fundamentally changed our understanding of the Universe, its origin, and its evolutionary process. General Relativity accurately describes a large number of phenomena on very different scales. As such, it has been very well tested and its remarkable predictions are compatible with most experimental and observational data. However, the observational and experimental results compatible with General Relativity fall in its vast majority under the weak gravitational field regime. In recent years, discrepancies between the data and the corresponding predictions of General Relativity have been observed and have generated intense research activity. One of the most critical aspects of General Relativity is the presence of singularities in extreme physical situations. These discrepancies indicate that either the parameters of the theory must be modified in the regime of strong field gravity/high energy and large space-time curvature, or the theory itself should be modified. In this book, we focus our attention on extended alternative gravity theories and the best astrophysical laboratories to probe the strong field regime: black holes, pulsars, and neutron stars.

Author: Subhajit Saha
Publisher: Springer
ISBN: 3319747061
Category : Science
Languages : en
Pages : 79

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Book Description
Based on the author’s own work and results obtained by renowned cosmologists, this short book provides a concise introduction to the relatively new research field of cosmological thermodynamics. Starting with a brief overview of basic cosmology and thermodynamics, the text gives an interesting account of the application of horizon thermodynamics to the homogeneous and isotropic Friedmann-Lemaitre-Robertson-Walker (FLRW) model, the inhomogeneous (Lemaitre-Tolman-Bondi) LTB model, and the gravitationally induced adiabatic particle creation scenario which is considered to be a viable alternative to the concordance Lambda-CDM model of the Universe. Both seasoned and new researchers in this field will appreciate the lucid presentation and the rich bibliography.

Author: Science News
Publisher: Diversion Books
ISBN: 1682304698
Category : Science
Languages : en
Pages : 242

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Book Description
From Science News comes a captivating anthology of articles exploring the concept of gravity and Albert Einstein’s enduring influence on the way humans understand it. From the ancient Greeks to Galileo to Sir Isaac Newton, gravity has long fascinated scientists and laypeople alike. One of the most mysterious forces in the universe, gravity as a theory has developed and changed over the centuries, but no single person has had as much to do with its evolution, and our understanding, as Albert Einstein. This collection of articles from the Science News archive looks at Einstein’s development of the general theory of relativity and considers its impact. Thanks to his revisions of Newton's theories, we have come to predict and understand phenomena such as gravitational waves, black holes, and the expansion of the universe. But Einstein did not just provide explanations—his work has raised new questions that scientists continue to investigate today. Since 1921, Society for Science & the Public has facilitated global understanding of important scientific discoveries and issues. Since the first publication of the Science News-Letter in 1922, they have grown their audience to millions of readers each year. Now, Science News exposes new readers to thrilling concepts and innovative theories in Einstein’s Gravity.

Author: Hess Peter O
Publisher: World Scientific
ISBN: 9813234296
Category : Science
Languages : en
Pages : 388

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Book Description
Walter Greiner (1935-2016) was a German physicist of the Goethe University, Frankfurt, well-known for his many contributions in scientific research and developments, in particular the field of nuclear physics. He was a well-respected science leader and a teacher who had supervised batches of young collaborators and students, many of whom are now leaders in both academics and industry worldwide. Greiner had a wide interest of science which covered atomic physics, heavy-ion physics, and nuclear astrophysics. Greiner co-founded GSI, the Helmholtz Centre for Heavy Ion Research, and the multi-disciplinary research center, FIAS (Frankfurt Institute for Advanced Studies). Besides numerous professorship with universities worldwide, including the University of Maryland, Greiner received many prestigious prizes in honor of his outstanding contributions, among others are the Otto Hahn Prize and the Max Born Prize. This memorial volume is a special tribute by Greiner's former colleagues, students, and friends honoring his contributions and passion in science. The volume begins with a writing by Greiner about his early days in science. The subsequent articles, comprising personal and scientific reminiscences of Walter Greiner, serve as timely reviews on various topics of current interest. Contents: Preface Reflections on My Youth and Early Years in Science (Walter Greiner) The Early Work of Walter Greiner (1960-1968) (Şerban Mişicu) Photon Scattering off Nuclei (Hartmuth Arenhövel) The QCD Phase Diagram from Statistical Model Analysis (Marcus Bleicher, Jan Steinheimer and Reinhard Stock) Why May Hydrodynamics Work for Classical Radiation Field? (Tamás S Biró) Chiral Symmetry Restoration and Deconfinement in Heavy-Ion Collisions (E L Bratkovskaya, W Cassing, P Moreau and A Palmese) The Physics Case for the √SNN ≈ 10 GeV Energy Region (J Cleymans) Untangling Simple Patterns in Intricate Atomic Nuclei (Jerry P Draayer, Kristina D Launey, Tomás Dytrych, Alison C Dreyfuss, Grigor H Sargsyan and Robert B Baker) Can One Determine the Neutrino Mass by Electron Capture? (Amand Faessler) Open and Hidden Charm in My Collaboration with Walter Greiner (Mark I Gorenstein) Dark Mater Compact Stars in Pseudo-Complex General Relativity (D Hadjimichef, G L Volkmer, R O Gomes and C A Zen Vasconcellos) Some Aspects of Nuclear Structure (J H Hamilton, A V Ramayya and E H Wang) The Power of the Geometrical Model of the Nucleus (Peter O Hess) Pseudo-Complex General Relativity: Theory (Peter O Hess and Thomas Boller) Observational Tests of the Pseudo-Complex Theory with Black Hole Imaging (Thomas Boller and Peter O Hess) From Strangeness Enhancement to Quark-Gluon Plasma Discovery (Peter Koch, Berndt Müller and Johann Rafelski) Time-Dependent Perturbation Theory as a Basis for Combined Many-Body-Perturbation and QED (Ingvar Lindgren) The Fullerene-Like Structure of Superheavy Element Z = 120 (Greinerium) -- A Tribute to Walter Greiner (Ş Mişicu and I N Mishustin) Cluster Radioactivity -- Past and Future (D N Poenaru and R A Gherghescu) Nuclear Mean-Field Models and Super-Heavy Elements (P-G Reinhard) The Octupole Collective Hamiltonian. Does It Follow the Example of the Quadrupole Case? (Stanislaw G Rohozinski and Leszek Próchniak) Modeling Hybrid Stars (S Schramm) Elliptic Flow and the Nuclear Equation of State (W Trautmann and H H Wolter) Black Holes and High Energy Physics: From Astrophysics to Lar

Author: Emmanuel N. Saridakis
Publisher: Springer Nature
ISBN: 3030837157
Category : Science
Languages : en
Pages : 631

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Book Description
With a focus on modified gravity this book presents a review of the recent developments in the fields of gravity and cosmology, presenting the state of the art, high-lighting the open problems, and outlining the directions of future research. General Relativity and the ΛCDM framework are currently the standard lore and constitute the concordance paradigm of cosmology. Nevertheless, long-standing open theoretical issues, as well as possible new observational ones arising from the explosive development of cosmology in the last two decades, offer the motivation and lead a large amount of research to be devoted in constructing various extensions and modifications. In this review all extended theories and scenarios are first examined under the light of theoretical consistency, and are then applied in various geometrical backgrounds, such as the cosmological and the spherical symmetric ones. Their predictions at both the background and perturbation levels, and concerning cosmology at early, intermediate and late times, are then confronted with the huge amount of observational data that astrophysics and cosmology has been able to offer in the last two decades. Theories, scenarios and models that successfully and efficiently pass the above steps are classified as viable and are candidates for the description of Nature, allowing readers to get a clear overview of the state of the art and where the field of modified gravity is likely to go. This work was performed in the framework of the COST European Action “Cosmology and Astrophysics Network for Theoretical Advances and Training Actions” - CANTATA.

Author: Gianluca Calcagni
Publisher: Springer
ISBN: 3642330363
Category : Science
Languages : en
Pages : 402

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Book Description
Quantum gravity has developed into a fast-growing subject in physics and it is expected that probing the high-energy and high-curvature regimes of gravitating systems will shed some light on how to eventually achieve an ultraviolet complete quantum theory of gravity. Such a theory would provide the much needed information about fundamental problems of classical gravity, such as the initial big-bang singularity, the cosmological constant problem, Planck scale physics and the early-time inflationary evolution of our Universe. While in the first part of this book concepts of quantum gravity are introduced and approached from different angles, the second part discusses these theories in connection with cosmological models and observations, thereby exploring which types of signatures of modern and mathematically rigorous frameworks can be detected by experiments. The third and final part briefly reviews the observational status of dark matter and dark energy, and introduces alternative cosmological models. Edited and authored by leading researchers in the field and cast into the form of a multi-author textbook at postgraduate level, this volume will be of benefit to all postgraduate students and newcomers from neighboring disciplines wishing to find a comprehensive guide for their future research.

Author: Stephen Webb
Publisher: Springer Science & Business Media
ISBN: 1461421942
Category : Science
Languages : en
Pages : 371

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Book Description
“New Eyes on the Universe – Twelve Cosmic Mysteries and the Tools We Need to Solve Them” gives an up-to-date broad overview of some of the key issues in modern astronomy and cosmology. It describes the vast amount of observational data that the new generation of observatories and telescopes are currently producing, and how that data might solve some of the outstanding puzzles inherent in our emerging world view. Included are questions such as: What is causing the Universe to blow itself apart? What could be powering the luminous gamma-ray bursters? Where is all the matter in the Universe? Do other Earths exist? Is there intelligent life out there? The renowned author explains clearly, without recourse to mathematics, why each question is puzzling and worthy of research. Included in the study of the wide range of sensitive and powerful instruments used by scientists to try and solve these problems are ones which capture electromagnetic radiation and ‘telescopes’ for cosmic rays, neutrinos, gravitational waves, and dark matter. This book discusses twelve areas of active astronomical research, ranging from the nature of dark energy to the existence or otherwise of extraterrestrial civilizations, and devotes one chapter to each topic. Although astronomers tackle each of these questions using information gleaned from all possible wavelengths and sources (and this is emphasized throughout the book), in this work the author dedicates each chapter to a particular observational method. One chapter covers X-ray telescopes for investigating black holes, while another uses infrared telescopes to learn more about planetary information.