Results 31 to 40 of about 6,479 (312)
Journal of High Energy Physics, 2020 We study a host of spacetimes where the Weyl curvature may be expressed algebraically in terms of an Abelian field strength. These include Type D spacetimes in four and higher dimensions which obey a simple quadratic relation between the field strength ...
Rashid Alawadhi +2 more
doaj +1 more source
Quantum Gravity: Motivations and Alternatives [PDF]
, 2009 The mutual conceptual incompatibility between General Relativity and Quantum Mechanics / Quantum Field Theory is generally seen as the most essential motivation for the development of a theory of Quantum Gravity.
Hedrich, Reiner
core +1 more source
4D spin-2 fields from 5D Chern-Simons theory
Journal of High Energy Physics, 2018 We consider a 5-dimensional Chern-Simons gauge theory for the isometry group of Anti-de-Sitter spacetime, AdS4+1 ≃ SO(4, 2), and invoke different dimensional reduction schemes in order to relate it to 4-dimensional spin-2 theories.
N. L. González Albornoz +3 more
doaj +1 more source
Journal of High Energy Physics, 2021 Primordial perturbations in our universe are believed to have a quantum origin, and can be described by the wavefunction of the universe (or equivalently, cosmological correlators). It follows that these observables must carry the imprint of the founding
Scott Melville, Enrico Pajer
doaj +1 more source
Teleparallel Theories of Gravity: Illuminating a Fully Invariant Approach [PDF]
, 2019 Teleparallel gravity and its popular generalization $f(T)$ gravity can be formulated as fully invariant (under both coordinate transformations and local Lorentz transformations) theories of gravity.
Coley, A. A. +9 more
core +1 more source
Spin effects in the effective field theory approach to Post-Minkowskian conservative dynamics
Journal of High Energy Physics, 2021 Building upon the worldline effective field theory (EFT) formalism for spinning bodies developed for the Post-Newtonian regime, we generalize the EFT approach to Post-Minkowskian (PM) dynamics to include rotational degrees of freedom in a manifestly ...
Zhengwen Liu +2 more
doaj +1 more source
Doomsdays in a modified theory of gravity: A classical and a quantum approach
Physics Letters B, 2017 By far cosmology is one of the most exciting subject to study, even more so with the current bulk of observations we have at hand. These observations might indicate different kinds of doomsdays, if dark energy follows certain patterns. Two of these doomsdays are the Little Rip (LR) and Little Sibling of the Big Rip (LSBR).
Imanol Albarran +3 more
openaire +5 more sources
Journal of High Energy Physics, 2020 A massive, nonrelativistic scalar field in an expanding spacetime is usually approximated by a pressureless perfect fluid, which leads to the standard conclusion that such a field can play the role of cold dark matter.
Borna Salehian +2 more
doaj +1 more source
Causality bounds on scalar-tensor EFTs
Journal of High Energy Physics, 2023 We compute the causality/positivity bounds on the Wilson coefficients of scalar-tensor effective field theories. Two-sided bounds are obtained by extracting IR information from UV physics via dispersion relations of scattering amplitudes, making use of ...
Dong-Yu Hong +2 more
doaj +1 more source
The philosophy behind quantum gravity [PDF]
, 2006 This paper investigates some of the philosophical and conceptual issues raised by the search for a quantum theory of gravity. It is critically discussed whether such a theory is necessary in the first place, and how much would be accomplished if it is ...
Zinkernagel, Henrik +2 more
core +1 more source