Results 41 to 50 of about 973 (226)
Cosmological Perturbations via Quantum Corrections in M-Theory
Universe, 2021 In the early universe, it is important to take into account the quantum effect of gravity to explain the feature of inflation. In this paper, we consider the M-theory effective action which consists of 11-dimensional supergravity and (Weyl)4 terms.
Kazuho Hiraga, Yoshifumi Hyakutake
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Nonconservative unimodular gravity: a viable cosmological scenario?
European Physical Journal C: Particles and Fields, 2022 In this work we review the issue of imposing the conservation of the energy–momentum tensor as a necessary condition to recover the equivalence between the unimodular gravity and General Relativity (GR) equipped with a cosmological constant.
Júlio C. Fabris +3 more
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ONE-DIMENSIONAL SIMULATIONS OF INHOMOGENEITY GROWTH IN PRESSURELESS GRAVITATING MATTER
Odessa Astronomical Publications, 2013 We study a model of the inhomogeneity growth in the Universe filled with a pressureless matter. The standard hydrodynamical equations for the cosmological perturbations in the comoving frame are treated taking into account all nonlinear terms.
V. I. Zhdanov, V. M. Sliusar
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Cosmological perturbations in generalised dark Lagrangians
Journal of High Energy Physics, 2018 We describe a new method to parameterise dark energy theories including massive gravity, elastic dark energy and tensor-metric theories. We first examine the existing framework which describes any second order Lagrangian which depends on the variation of
James Edholm, Jonathan Pearson
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Guiding and Manipulating Light Fields in Microstructured Liquid Crystals
Advanced Physics Research, EarlyView.This review summarizes recent advances in guided‐wave optics enabled by microstructured liquid crystal (LC) devices, covering their fundamental material properties, key degree of freedom for dynamic light field manipulations. The advances of linear guided‐wave optics, nonlinear‐optics with spatial optical solitons, and microlasers in LC‐based devices ...
Shan‐shan Chang +2 more
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Evolution of Nonlinear Cosmological Perturbations
Physical Review Letters, 2005 We define fully non-perturbative generalizations of the uniform density and comoving curvature perturbations, which are known, in the linear theory, to be conserved on sufficiently large scales for adiabatic perturbations. Our non-linear generalizations are defined geometrically, independently of any coordinate system.
Langlois, David, Vernizzi, F.
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Appearances are deceptive: can graviton have a mass?
Journal of High Energy PhysicsWe study the dynamics of linear gravitational perturbations on cosmological backgrounds of massive fermionic fields. We observe that, when gravitational and matter action are expanded to quadratic order in gravitational perturbations on cosmological ...
Leihua Liu, Tomislav Prokopec
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Scalar perturbations in cosmological f(R) models: the cosmic screening approach
European Physical Journal C: Particles and Fields, 2018 We investigate cosmological perturbations for nonlinear f(R) models within the cosmic screening approach. Matter is considered both in the form of a set of discrete point-like massive bodies and in the form of a continuous pressureless perfect fluid.
Özgür Akarsu +4 more
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7000 Years of Aboriginal Mining at Sugarloaf Hill in the Riverland Region of South Australia
Archaeology in Oceania, EarlyView.ABSTRACT Silcrete and chert are commonly represented in Aboriginal archaeological lithic assemblages across large parts of the southwestern Murray‐Darling Basin (MDB). In South Australia (SA), these materials were sourced from a series of quarries located along the incised course of the Murray River through the upper Riverland region.
Craig Westell +8 more
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Cosmological Perturbations [PDF]
, 2002 Lecture notes. Proceedings of the 1st Aegean Summer School on Cosmology (Springer LNP).
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