Download or read book Nonlocal Gravity written by Bahram Mashhoon and published by Oxford University Press. This book was released on 2017-05-05 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: Relativity theory is based on a postulate of locality, which means that the past history of the observer is not directly taken into account. This book argues that the past history should be taken into account. In this way, nonlocality—-in the sense of history dependence—-is introduced into relativity theory. The deep connection between inertia and gravitation suggests that gravity could be nonlocal, and in nonlocal gravity the fading gravitational memory of past events must then be taken into account. Along this line of thought, a classical nonlocal generalization of Einstein's theory of gravitation has recently been developed. A significant consequence of this theory is that the nonlocal aspect of gravity appears to simulate dark matter. According to nonlocal gravity theory, what astronomers attribute to dark matter should instead be due to the nonlocality of gravitation. Nonlocality dominates on the scale of galaxies and beyond. Memory fades with time; therefore, the nonlocal aspect of gravity becomes weaker as the universe expands. The implications of nonlocal gravity are explored in this book for gravitational lensing, gravitational radiation, the gravitational physics of the Solar System and the internal dynamics of nearby galaxies, as well as clusters of galaxies. This approach is extended to nonlocal Newtonian cosmology, where the attraction of gravity fades with the expansion of the universe. Thus far, scientists have only compared some of the consequences of nonlocal gravity with astronomical observations.
Download or read book Nonlocal Gravity and Structure in the Universe written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The observed acceleration of the Universe can be explained by modifying general relativity. One such attempt is the nonlocal model of Deser and Woodard. Here we fix the background cosmology using results from the Planck satellite and examine the predictions of nonlocal gravity for the evolution of structure in the universe, confronting the model with three tests: gravitational lensing, redshift space distortions, and the estimator of gravity $E_G$. Current data favor general relativity (GR) over nonlocal gravity: fixing primordial cosmology with the best fit parameters from Planck leads to weak lensing results favoring GR by 5.9 sigma; redshift space distortions measurements of the growth rate preferring GR by 7.8 sigma; and the single measurement of $E_G$ favoring GR, but by less than 1-sigma. The significance holds up even after the parameters are allowed to vary within Planck limits. The larger lesson is that a successful modified gravity model will likely have to suppress the growth of structure compared to general relativity.
Download or read book Lectures On Non perturbative Canonical Gravity written by Abhay Ashtekar and published by World Scientific. This book was released on 1991-07-03 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Notes prepared in Collaboration with Ranjeet S Tate It is now generally recognized that perturbative field theoretical methods that have been highly successful in the quantum description of non-gravitational interactions cannot be used as a means of constructing a quantum theory of gravity. The primary aim of the book is to present an up- to-date account of a non-perturbative, canonical quantization program for gravity. Many of the technical results obtained in the process are of interest also to differential geometry, classical general relativity and QCD. The program as a whole was highlighted in virtually every major conference in gravitational physics over the past three years.
Download or read book Effects of Non locality in Gravity and Quantum Theory written by Jens Boos and published by Springer Nature. This book was released on 2021-10-28 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is devoted to the systematic study of non-local theories that respect Lorentz invariance and are devoid of new, unphysical degrees of freedom. Such theories are attractive for phenomenological applications since they are mostly unconstrained by current experiments. Non-locality has played an increasingly important role in the physics of the last decades, appearing in effective actions in quantum field theory, and arising naturally in string theory and non-commutative geometry. It may even be a necessary ingredient for quantum theories of gravity. It is a feature of quantum entanglement, and may even solve the long-standing black hole information loss problem. “Non-locality” is a broad concept with many promising and fruitful applications in theoretical and mathematical physics. After a historical and pedagogical introduction into the concept of non-locality the author develops the notion of non-local Green functions to study various non-local weak-field problems in quantum mechanics, quantum field theory, gravity, and quantum field theory in curved spacetime. This thesis fills a gap in the literature by providing a self-contained exploration of weak-field effects in non-local theories, thereby establishing a “non-local intuition” which may serve as a stepping stone for studies of the full, non-linear problem of non-locality.
Download or read book Modified Gravity and Cosmology written by Emmanuel N. Saridakis and published by Springer Nature. This book was released on 2021-12-10 with total page 631 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Introduction to Modified Gravity written by Albert Petrov and published by Springer Nature. This book was released on 2023-11-16 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews various modified gravity models, including those with modifications in the pure gravitational sector; those involving extra fields, that is, scalar-tensor and vector-tensor gravity theories; gravity models with Lorentz symmetry breaking; and nonlocal gravity models. The authors discuss both classical and quantum aspects of these theories. The book is unique in bringing together all the current alternatives to Einstein gravity in one source and serves as an excellent starting point for graduate students and other newcomers seeking an overview. This second edition has been expanded with new results from a variety of approaches including f(R,Q,P) gravity, galileon gravity and massive gravity. Extended discussions of Lorentz-breaking terms and of non-local field theory have been added and a completely new chapter is devoted to models based on non-Riemannian geometry.
Download or read book Gravity and Quantum Non Linearity written by Timothy Reeves and published by Authors On Line Ltd. This book was released on 2004-10 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: For many years Maxwell's equations were mute testimony to the Lorentz coordinate transformations of special relativity, but the significance of this transformation was not fully understood until relativity itself had been discovered. The author of this book claims that an oversight has once again occurred in fundamental physics. A direct link between Quantum Mechanics and Gravity - perhaps the biggest scientific enigma of all time - has been overlooked. In an entirely novel approach to Quantum-Gravity, this book suggests that Gravity is the manifestation of a very weak non-linearity in Quantum Mechanics; a non-linearity only apparent in the presence of large quantities of matter or very condensed wave functions. The reader will discover how this non-linearity is a natural consequence of a particular interpretation of the Quantum Equations. This book however, does not share the same genre of totalising theories that emphatically and triumphantly declare a new dawn. Instead its thesis can only present itself as a fascinating hypothesis submitted for consideration. Should the theory presented here prove its mettle, then it would provide the key to opening up new vistas of theoretical and experimental research, thus helping to clear the conceptual log jam in which contemporary fundamental physics finds itself.
Download or read book Noether Symmetries in Theories of Gravity written by Francesco Bajardi and published by Cambridge University Press. This book was released on 2022-11-24 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume summarizes the many alternatives and extensions to Einstein's General Theory of Relativity, and shows how symmetry principles can be applied to identify physically viable models. The first part of the book establishes the foundations of classical field theory, providing an introduction to symmetry groups and the Noether theorems. A quick overview of general relativity is provided, including discussion of its successes and shortcomings, then several theories of gravity are presented and their main features are summarized. In the second part, the 'Noether Symmetry Approach' is applied to theories of gravity to identify those which contain symmetries. In the third part of the book these selected models are tested through comparison with the latest experiments and observations. This constrains the free parameters in the selected models to fit the current data, demonstrating a useful approach that will allow researchers to construct and constrain modified gravity models for further applications.
Download or read book 100 Years of Chronogeometrodynamics The Status of the Einstein s Theory of Gravitation in Its Centennial Year written by Lorenzo Iorio and published by MDPI. This book was released on 2018-07-10 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Download or read book The Search for Non Newtonian Gravity written by Ephraim Fischbach and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: A history of the attempts to test the predictions of Newtonian Gravity, describing in detail recent experimental efforts to verify both the inverse-square law and the Equivalence Principle. Interest in these questions has increased in recent years, as it has become recognised that deviations from Newtonian gravity could be a signal for a new fundamental force in nature. This is the first book devoted entirely to this subject, and will thus be useful to both graduate students and researchers interested in this field. It describes the ideas that underlie searches for such deviations, focusing on macroscopic tests. A comprehensive bibliography of some 450 entries supplements the text.
Download or read book Lie Theory and Its Applications in Physics written by Vladimir Dobrev and published by Springer. This book was released on 2016-12-10 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents modern trends in the area of symmetries and their applications based on contributions from the workshop "Lie Theory and Its Applications in Physics", held near Varna, Bulgaria, in June 2015. Traditionally, Lie theory is a tool to build mathematical models for physical systems.Recently, the trend has been towards geometrization of the mathematical description of physical systems and objects. A geometric approach to a system yields in general some notion of symmetry, which is very helpful in understanding its structure. Geometrization and symmetries are employed in their widest sense, embracing representation theory, algebraic geometry, number theory, infinite-dimensional Lie algebras and groups, superalgebras and supergroups, groups and quantum groups, noncommutative geometry, symmetries of linear and nonlinear partial differential operators (PDO), special functions, and others. Furthermore, the necessary tools from functional analysis are included.“div>This is a large interdisciplinary and interrelated field, and the present volume is suitable for a broad audience of mathematicians, mathematical physicists, and theoretical physicists, including researchers and graduate students interested in Lie Theory.
Download or read book Gravity and the Quantum written by Jasjeet Singh Bagla and published by Springer. This book was released on 2017-02-23 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a compilation of in-depth articles and reviews on key topics within gravitation, cosmology and related issues. It is a celebratory volume dedicated to Prof. Thanu Padmanabhan ("Paddy"), the renowned relativist and cosmologist from IUCAA, India, on the occasion of his 60th birthday. The authors, many of them leaders of their fields, are all colleagues, collaborators and former students of Paddy, who have worked with him over a research career spanning more than four decades. Paddy is a scientist of diverse interests, who attaches great importance to teaching. With this in mind, the aim of this compilation is to provide an accessible pedagogic introduction to, and overview of, various important topics in cosmology, gravitation and astrophysics. As such it will be an invaluable resource for scientists, graduate students and also advanced undergraduates seeking to broaden their horizons.
Download or read book Gravitational Theories Beyond General Relativity written by Iberê Kuntz and published by Springer. This book was released on 2020-08-14 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the success of general relativity in explaining classical gravitational phenomena, several problems at the interface between gravitation and high energy physics still remain open. The purpose of this thesis is to explore quantum gravity and its phenomenological consequences for dark matter, gravitational waves and inflation. A new formalism to classify gravitational theories based on their degrees of freedom is introduced and, in light of this classification, it is argued that dark matter is no different from modified gravity. Gravitational waves are shown to be damped due to quantum degrees of freedom. The consequences for gravitational wave events are also discussed. The non-minimal coupling of the Higgs boson to gravity is studied in connection with Starobinsky inflation and its implications for the vacuum instability problem is analyzed.
Download or read book Structure Formation in Modified Gravity Cosmologies written by Alexandre Barreira and published by Springer. This book was released on 2016-05-03 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique thesis covers all aspects of theories of gravity beyond Einstein’s General Relativity, from setting up the equations that describe the evolution of perturbations, to determining the best-fitting parameters using constraints like the microwave background radiation, and ultimately to the later stages of structure formation using state-of-the-art N-body simulations and comparing them to observations of galaxies, clusters and other large-scale structures. This truly ground-breaking work puts the study of modified gravity models on the same footing as the standard model of cosmology. Since the discovery of the accelerating expansion of the Universe, marked by the awarding of the 2011 Nobel Prize in Physics, there has been a growing interest in understanding what drives that acceleration. One possible explanation lies in theories of gravity beyond Einstein’s General Relativity. This thesis addresses all aspects of the problem, an approach that is crucial to avoiding potentially catastrophic biases in the interpretation of upcoming observational missions.
Download or read book Quantum Nonlocality and Reality written by Mary Bell and published by Cambridge University Press. This book was released on 2016-09-19 with total page 459 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combining twenty-six original essays written by an impressive line-up of distinguished physicists and philosophers of physics, this anthology reflects some of the latest thoughts by leading experts on the influence of Bell's theorem on quantum physics. Essays progress from John Bell's character and background, through studies of his main work, and on to more speculative ideas, addressing the controversies surrounding the theorem, and investigating the theorem's meaning and its deep implications for the nature of physical reality. Combined, they present a powerful comment on the undeniable significance of Bell's theorem for the development of ideas in quantum physics over the past 50 years. Questions surrounding the assumptions and significance of Bell's work still inspire discussion in the field of quantum physics. Adding to this with a theoretical and philosophical perspective, this balanced anthology is an indispensable volume for students and researchers interested in the philosophy of physics and the foundations of quantum mechanics.
Download or read book From Theory to Observational Constraints in Nonlocal Gravity written by Yves Dirian and published by . This book was released on 2018 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantum Theory and Symmetries with Lie Theory and Its Applications in Physics Volume 1 written by Vladimir Dobrev and published by Springer. This book was released on 2018-11-28 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the first volume of proceedings from the joint conference X International Symposium “Quantum Theory and Symmetries” (QTS-X) and XII International Workshop “Lie Theory and Its Applications in Physics” (LT-XII), held on 19–25 June 2017 in Varna, Bulgaria. The QTS series was founded on the core principle that symmetries underlie all descriptions of quantum systems. It has since evolved into a symposium at the forefront of theoretical and mathematical physics. The LT series covers the whole field of Lie theory in its widest sense, together with its applications in many areas of physics. As an interface between mathematics and physics, the workshop serves as a meeting place for mathematicians and theoretical and mathematical physicists. In dividing the material between the two volumes, the Editor has sought to select papers that are more oriented toward mathematics for the first volume, and those focusing more on physics for the second. However, this division is relative, since many papers are equally suitable for either volume. The topics addressed in this volume represent the latest trends in the fields covered by the joint conferences: representation theory, integrability, entanglement, quantum groups, number theory, conformal geometry, quantum affine superalgebras, noncommutative geometry. Further, they present various mathematical results: on minuscule modules, symmetry breaking operators, Kashiwara crystals, meta-conformal invariance, the superintegrable Zernike system.
