Search Results - "cosmological constant"
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The cosmological constant problem and gravity in the infrared
Published 2016“…We will discuss the cosmological constant problem in detail, paying special attention to how it affects the global structure of a space-time whose dynamics are dictated by GR. …”
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Self-tuning and the cosmological constant problem
Published 2023Subjects: “…Self-tuning; Cosmological Constant Problem; Scalar Fields; Fab Four; Massive Gravity; Cosmology; Gravity; General Relativity Vacuum Energy Quantum Field Theory Anti-de Sitter Space Exchange Amplitudes…”
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Dynamics of early & late universe cosmology
Published 2018Subjects: “…cosmological constant problem…”
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An étude on global vacuum energy sequester
Published 2017“…Recently two of the authors proposed a mechanism of vacuum energy sequester as a means of protecting the observable cosmological constant from quantum radiative corrections. …”
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The cosmology of the Fab-Four
Published 2012“…We have recently proposed a novel self tuning mechanism to alleviate the famous cosmological constant problem, based on the general scalar tensor theory proposed by Horndeski. …”
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General relativity from three-forms in seven dimensions
Published 2017“…Possibly the most interesting point of this construction is that the dimensionally reduced theory is GR with a non-zero cosmological constant, and the value of the cosmological constant is directly related to the size of . …”
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Sequestering effects on and of vacuum decay
Published 2016“…This means that the cosmological constant in de Sitter descendant vacua remains insensitive to phase transitions which may have occurred in the course of its cosmic history.…”
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Self-tuning and the derivation of a class of scalar-tensor theories
Published 2012“…These arose from attempts to analyse the cosmological constant problem within the context of Horndeski's most general scalar tensor theory. …”
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Geometrical measurements in three-dimensional quantum gravity
Published 2002“…A set of observables is described for the topological quantum field theory which describes quantum gravity in three space-time dimensions with positive signature and positive cosmological constant. The simplest examples measure the distances between points, giving spectra and probabilities which have a geometrical interpretation. …”
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Classical and quantum modifications of gravity
Published 2013“…We go on to demonstrate sufficient conditions for a theory in this class to share a solution space equal to that of Einstein’s equations plus a cosmological constant, before determining the cosmology these extra solutions may have when present.…”
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Disformally self-tuning gravity
Published 2016“…Through allowing a disformal coupling to matter we are able to extend the Fab Four model and construct a new class of theories that are able to tune away the cosmological constant on Friedmann-Lemaitre-Robertson-Walker backgrounds.…”
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Dark energy: EFTs and supergravity
Published 2022“…We conclude that quintessence faces more challenges than a true cosmological constant, to the point that quintessence is very unattractive for model building modulo a ruling out of the cosmological constant by observations. …”
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Reducing heterotic M-theory to five dimensional supergravity on a manifold with boundary
Published 2011“…The effect of gaugino condensation on the fermion boundary conditions leads to a `twist' in the chirality of the gravitino which can provide an uplifting mechanism in the vacuum energy to cancel the cosmological constant after moduli stabilisation.…”
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Aspects of de Sitter Vacua in Theoretical Cosmology
Published 2025“…We propose a “probabilistic” argument to explain the small cosmological constant instead of the dominant anthropic principle. …”
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General second-order scalar-tensor theory and self-tuning
Published 2012“…Spacetime curvature can be screened from the net cosmological constant at any given moment because we allow the scalar field to break Poincar\'e invariance on the self-tuning vacua, thereby evading the Weinberg no-go theorem. …”
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A proposed experimental search for chameleons using asymmetric parallel plates
Published 2016“…Light scalar fields coupled to matter are a common consequence of theories of dark energy and attempts to solve the cosmological constant problem. The chameleon screening mechanism is commonly invoked in order to suppress the fifth forces mediated by these scalars, sufficiently to avoid current experimental constraints, without fine tuning. …”
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An interacting scenario for dark energy in a Bianchi type-I universe
Published 2014“…However, in both cases, the DE EoS parameter ωde ultimately (i.e. at z = −1) tends to the cosmological constant (ωde = −1). Moreover, we fix the cosmological bound on the anisotropy parameter K by using recent observational data about the Hubble parameter.…”
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A new class of inhomogeneous cosmological models with electromagnetic field in normal gauge for Lyra's manifold.
Published 2011“…It has been found that the displacement vector β(t) behaves like the cosmological constant Λ in the normal gauge treatment and the solutions are consistent with the recent observations of Type Ia supernovae. …”
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Topics in 2 + 1 gravity and conformal field theory
Published 2009“…We study the Hamiltonian dynamics for a system of two colliding point particles coupled to (2+1)-dimensional gravity with a negative cosmological constant by anchoring the dynamics of the system to its spatial infinity. …”
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