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Showing 1 to 20 of 32 for “"modified gravity"”.

  1. Modified Gravity with Torsion

    Negreanu, Carina SuzanaUniversity of Cambridge2019

    … thesis focuses on applications of a particular modified gravity theory, the extended Weyl Gauge Theory (eWGT), that was recently developed by Prof. Lasenby and Prof. Hobson. The applications corresponds to subsets of the full theory that are applicable to different cosmological and astrophysical …

    cambridge Repository record

  2. Topics in modified gravity

    Abdelwahab, Mohamed Elshazli SirelakhatimDepartment of Mathematics and Applied Mathematics2012

    … gravitation. It replaced the Newtonian theory of gravity which was presented in the Principia in 1687. The fundamental idea in GR is that gravity is a manifestation of the curvature of the spacetime, while in Newton’s theory gravity acts directly as a force between bodies. Many of the predictions …

    cape-town Repository record

  3. Astrophysical tests of modified gravity

    Sakstein, Jeremy AaronUniversity of Cambridge2014

    … relativity has been the accepted theory of gravity for nearly a century but how well have we really tested it? The laws of gravity have been probed in our solar system to extremely high precision using several different tests and general relativity has passed each one with flying colours. …

    cambridge Repository record

  4. Aspects of Screened Modified Gravity

    Procter, NathanUniversity of Cambridge2020

    … and these have motivated various theories of modified gravity that challenge general relativity. In order to pass the stringent observational tests on a solar system level, the deviation of modified gravities from general relativity must be suppressed. This is known as screening, and different …

    cambridge Repository record

  5. Exotic spherically symmetric objects in modified gravity

    Karanasou, Vasiliki2026

    tartu

  6. Cosmological And Astrophysical Tests Of Modified Gravity

    Gao, Caixia2019

    … cmb are found. The second one is drgt massive gravity. In this theory a charged black hole solution is found and compared to those in gr, folloby constraints on the parameter space. The third one is a general massive gravity theory which shares the same background equation with the massless …

    mississippi Repository record

  7. Modified Gravity and Cosmology on the Largest Scales

    Terrana, Alexandra Eileen2018

    … particularly dark energy, cosmic acceleration, modified gravity, and cosmic variance. Following an overview of the current understanding of the standard cosmological model in chapter 1, three pertinent topics are discussed in detail. A common theme among all chapters is the desire to explain the …

    york Repository record

  8. Constrained dynamics and higher derivative systems in modified gravity

    Chen, Tai-junUniversity of Cambridge2015

    … formalism to the most general higher derivative gravity theory where the action is not only linearly dependent on the Ricci scalar but also the quadratic curvature invariants in four-dimensional spacetime. We find that the instabilities can be removed by the judicious addition of constraints at …

    cambridge Repository record

  9. Causality and the initial value problem in Modified Gravity

    Papallo, GiuseppeUniversity of Cambridge2019

    … symmetric spacetimes in Einstein–Gauss–Bonnet gravity (a Lovelock theory). In Lovelock theories, gravitons can propagate faster or slower than light. We show that, thanks to this property, it is possible for them to experience a negative time delay. It was recently argued that this feature …

    cambridge Repository record

  10. Vibrations and instabilities of a disk galaxy with modified gravity.

    Erickson, Stanley ArvindMassachusetts Institute of Technology1974

    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1974.

    mit Repository record

  11. The Effective Field Theory Approach to Fluid Dynamics, Modified Gravity Theories, and Cosmology

    Wang, Junpu2013

    … be built by naturally coupling the fluid EFT to gravity. From the EFT point of view, GR is the unique low energy theory for the spin-2 graviton field and any infrared modification corresponds to adding new degrees of freedom. We focus on two popular classes of modified gravity models, --- the …

    columbia-diss Repository record

  12. Gravitational collapse, compact objects and gravitational waves in General Relativity and modified gravity

    Rosca-Mead, RoxanaUniversity of Cambridge2019

    … us with a window into the dynamics of strong gravity as well as the opportunity to test modified gravity and alternative theories in the strong regime, by confirming deviations from GR or constraining such theories. Why is General Relativity not enough though? It has passed all the tests so …

    cambridge Repository record

  13. A f(R)esh take on gravity

    Worsley, JessDepartment of Astronomy2025

    This thesis explores perturbations in f(R) modified gravity theories, with a focus on understanding the growth of large-scale structures in the Universe. Modified gravity models, particularly f(R) theories, offer an alternative explanation for cosmic acceleration without invoking dark energy. The …

    cape-town Repository record

  14. Galaxy-Scale Signatures of Screened Modified Gravities

    Naik, AneeshUniversity of Cambridge2020

    In recent years, theories of gravity incorporating a scalar field coupled to gravity---'scalar-tensor' theories---have been subject to increased attention. In these theories, the scalar field mediates gravitational-strength 'fifth forces'. For such scalar fields to retain cosmological relevance …

    cambridge Repository record

  15. Crowded Out: The Effect of Sex Ratios on the Sex Worker Labor Market and Migration in India

    Dickerson, Michael2016

    … effects the migration of sex workers. By using a modified gravity model of migration the results in this paper indicates that an over supply of sex workers in a local market leads to a crowding out effect, and pushes the women to migrate to districts with more men than women. This paper …

    usfca Repository record

  16. On aspects of infinite derivatives field theories & infinite derivative gravity

    Teimouri, Ilia, Gratus, JonathanLancaster University2018

    Infinite derivative theory of gravity is a modification to the general theory of relativity. Such modification maintains the massless graviton as the only true physical degree of freedom and avoids ghosts. Moreover, this class of modified gravity can address classical singularities. In this thesis …

    lancaster Repository record

  17. Cosmological constraints using 2- and 3-point correlations with meerkat, the ska and other surveys

    Randrianjanahary, Liantsoa FinaritraUniversty of the Western Cape2024

    … and what they mean for dynamical dark energy and modified gravity. We account for telescope beam effects, instrumental noise, foreground avoidance, the Alcock-Paczynski effect, and theoretical modeling errors in the correlators. The investigation also includes assessments of 21-cm clustering bias …

    western-cape Repository record

  18. NEW GRAVITATIONAL INTERACTIONS IN COSMOLOGY —- FROM EFFECTIVE FIELD THEORY TO OBSERVATION

    Liang, Qiuyue2023

    … suggests an interaction between neutrinos and gravity could help alleviate this tension. I then turn to more formal considerations of Effective Field Theories (EFTs) in cosmology. In particular, I show how to generalize the EFT of the binary black hole system to extended objects, constructing …

    penn Repository record

  19. Topics in Theoretical Gravity

    Lundgren, Andrew2008

    … of such observatories. Chapter 5 explores a modified theory of gravity called F(R) gravity which was proposed to solve the dark energy problem. We consider forms of F(R) that are intended to mimic standard General Relativity at high densities, but have low-density behavior that can explain …

    cornell Repository record

  20. Potential impacts of hard infrastructure development on agricultural trade

    Al-Maamari, Aaisha, author, Countryman, Amanda, advisor, Thilmany, Dawn, committee member, Pena, Anita, committee memberColorado State University. Libraries2017

    … prevalence and patterns of agricultural trade. A modified gravity model of trade has been used to measure the impact of different trade barriers on the trade of food, animal, vegetable and aggregated agricultural products. Results show that the distance between countries and hard infrastructure …

    colostate Repository record

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