Results 11 to 20 of about 59,420 (206)

No Intrinsic Decoherence of Inflationary Cosmological Perturbations

open access: yesUniverse, 2022
After a brief summary of the four main veins in the treatment of decoherence and quantum to classical transition in cosmology since the 1980s, we focus on one of these veins in the study of quantum decoherence of cosmological perturbations in ...
Jen-Tsung Hsiang, Bei-Lok Hu
doaj   +1 more source

Unravelling cosmological perturbations

open access: yesPhysics Letters B, 2018
We explain in detail the quantum-to-classical transition for the cosmological perturbations using only the standard rules of quantum mechanics: the Schrödinger equation and Born's rule applied to a subsystem. We show that the conditioned, i.e. intrinsic,
Timothy J. Hollowood
doaj   +1 more source

Cosmological perturbations [PDF]

open access: yes, 2009
We review the study of inhomogeneous perturbations about a homogeneous and isotropic background cosmology. We adopt a coordinate based approach, but give geometrical interpretations of metric perturbations in terms of the expansion, shear and curvature ...
Malik, Karim A., Wands, David
core   +2 more sources

Cosmological Perturbations [PDF]

open access: yes, 2002
The aim of these lecture notes is to familiarize graduate students and beginning postgraduates with the basic ideas of linear cosmological perturbation theory and of structure formation scenarios.
Tsagas, Christos G.
core   +2 more sources

Cosmological Perturbations in Double Field Theory

open access: yesJournal of High Energy Physics, 2023
We explore perturbative double field theory about time-dependent (cosmological) backgrounds to cubic order. To this order the theory is consistent in a weakly constrained sense, so that for a toroidal geometry it encodes both momentum and genuine winding
Olaf Hohm, Allison F. Pinto
doaj   +1 more source

Braneworld cosmological perturbations in teleparallel gravity

open access: yesPhysics Letters B, 2015
In this paper we find the fully gauge invariant cosmological perturbation equations in braneworld teleparallel gravity. In this theory, perturbations are the result of small fluctuations in the pentad field. We derive the gauge invariant 'potentials' for
A. Behboodi, K. Nozari
doaj   +1 more source

Configurational entropy and instability of tachyonic braneworld

open access: yesPhysics Letters B, 2020
We consider tachyonic braneworld with a bulk cosmological constant and investigate a configurational entropy of various magnitudes of scale factor. It is found that for a bulk negative/zero cosmological constant, the configurational entropy has a global ...
Chong Oh Lee
doaj   +1 more source

On the Back Reaction Problem for Gravitational Perturbations [PDF]

open access: yes, 1996
We derive the effective energy-momentum tensor for cosmological perturbations and prove its gauge-invariance. The result is applied to study the influence of perturbations on the behaviour of the Friedmann background in inflationary Universe scenarios ...
A. A. Starobinsky   +17 more
core   +2 more sources

Stabilizing homogeneous black strings in AdS

open access: yesJournal of High Energy Physics, 2020
It is known that homogenous black strings in flat spacetime are unstable under long wavelength perturbations. Recently, by including scalar fields that depend on the extended coordinates only, homogenous black strings have been constructed in the ...
Adolfo Cisterna   +2 more
doaj   +1 more source

The Osmium Isotope Signature of Phanerozoic Large Igneous Provinces

open access: yesGeophysical Monograph Series, Page 229-246., 2021

Exploring the links between Large Igneous Provinces and dramatic environmental impact

An emerging consensus suggests that Large Igneous Provinces (LIPs) and Silicic LIPs (SLIPs) are a significant driver of dramatic global environmental and biological changes, including mass extinctions.
Alexander J. Dickson   +2 more
wiley  

+1 more source

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