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A hypothetical dark energy component may have an equation of state that is different from a cosmological constant and possibly even changing in time. The spacing of the cosmic microwave background peaks is sensitive to the ratio of the…

Astrophysics · Physics 2007-05-23 Michael Doran , Matthew Lilley , Jan Schwindt , Christof Wetterich

We calculate the power spectrum of cosmological perturbations originated from quantum vacuum fluctuations in bouncing scenarios proposed in Ref.~\cite{chamseddine2014cosmology} in the framework of mimetic cosmology. We show that all…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-02 Idaiane L. Machado , Dêivid R. da Silva , Nelson Pinto-Neto

We discuss the gauge parameter dependence of particle spectra in statistical quantum electrodynamics and conclude that the electron spectrum is gauge-parameter dependent. The physical spectrum being obtained in the Landau gauge, which leads…

High Energy Physics - Phenomenology · Physics 2016-08-15 D. Oliva Agüero , H. Pérez Rojas , A. Pérez Martínez , A. Amézaga Hechavarría

We investigate the cosmological dependence and the constraining power of large-scale galaxy correlations, including all redshift-distortions, wide-angle, lensing and gravitational potential effects on linear scales. We analyze the…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-25 Alvise Raccanelli , Francesco Montanari , Daniele Bertacca , Olivier Doré , Ruth Durrer

The existence of cosmic fields made from yet unknown light bosons is predicted in many extensions to the Standard Model. They are especially of interest as possible constituents of dark matter. To detect such light and weakly interacting…

High Energy Physics - Phenomenology · Physics 2026-01-30 Sebastian Lahs , Daniel Comparat , Fiona Kirk , Benjamin Roberts

We show that the standard Lorentz transformations admit an invariant mass (length) scale, such as the Planck scale. In other words, the frame independence of such scale is built-in within those transformations, and one does not need to…

General Relativity and Quantum Cosmology · Physics 2019-04-17 Pasquale Bosso , Saurya Das

The conventional cosmological perturbation theory has been performed under the assumption that we know the whole spatial region of the universe with infinite volume. This is, however, not the case in the actual observations because…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Takahiro Tanaka , Yuko Urakawa

An artificial scale of observable cosmological constant is dynamically related to its natural bare value due to an installation of relevant coherent state for the inflationary field in a finite volume of early Universe, because of…

General Relativity and Quantum Cosmology · Physics 2014-01-15 V. V. Kiselev

We are at a specific period of modern cosmology, during which the large increase of the amount of data leads to the idea that the determination of cosmological parameters has been achieved with a rather good precision. There is a large…

Astrophysics · Physics 2017-08-23 A. Blanchard

We propose a new approach for modeling the quantum ring single particle energy spectrum. The approach is based on separation of variables in the Schr\"odinger equation in oblate spheroidal coordinates. We consider a model of a spheroidal…

Mesoscale and Nanoscale Physics · Physics 2015-09-17 V. A. Roudnev A. M. Puchkov , A. V. Kozhedub

The quantum field theoretic prediction for the vacuum energy density leads to a value for the effective cosmological constant that is incorrect by between 60 to 120 orders of magnitude. We review an old proposal of replacing Einstein's…

General Relativity and Quantum Cosmology · Physics 2011-10-24 George F. R. Ellis , Henk van Elst , Jeff Murugan , Jean-Philippe Uzan

Duality transformations within the quantum mechanics of a finite number of degrees of freedom can be regarded as the dependence of the notion of a quantum, i.e., an elementary excitation of the vacuum, on the observer on classical phase…

High Energy Physics - Theory · Physics 2015-06-26 J. M. Isidro

The effect of the cosmological constant on the curvature of light due to an isolated spherical mass is recalculated without using the lens equation and compared to a lensing cluster.

Astrophysics · Physics 2009-06-23 Thomas Schucker

High precision cosmological observations in last decade suggest that about 70% of our universe's energy density is in so called "Dark Energy" (DE). Observations show that DE has negative effective pressure and therefore unlike conventional…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-01 Lado Samushia

We present here the transformations required to recast the Robertson-Walker metric and Friedmann-Robertson-Walker equations in terms of observer-dependent coordinates for several commonly assumed cosmologies. The overriding motivation is…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-26 Fulvio Melia , Majd Abdelqader

The possibility that the universe may have a fundamental and positive cosmological constant has motivated an interesting cosmological model, in which initially the universe is in a cosmological constant sea, then the local quantum…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Yun-Song Piao

We study the consequences of the $f(R/\Box)$ gravity models for the Solar system and the large scale structure of the universe. The spherically symmetric solutions can be used to obtain bounds on the constant and the linear parts of the…

General Relativity and Quantum Cosmology · Physics 2008-12-18 Tomi S. Koivisto

A local observer can measure only the values of fields at the point of his own position. By exploring the coordinate transformation between two Fermi frames, it is shown that two observers, having the same instantaneous position and…

General Relativity and Quantum Cosmology · Physics 2007-05-23 H. Nikolic

It was recently suggested that the gravitational action could contain a scale-dependent cosmological term, depending on the length or momentum scale characteristic of the processes under consideration. In this work we explore a simple…

General Relativity and Quantum Cosmology · Physics 2009-10-31 G. Modanese

The canonical cosmological model to explain the recent acceleration of the universe relies on a cosmological constant, and most dynamical dark energy and modified gravity model alternatives are based on scalar fields. Still, further…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-10 C. S. C. M. Coelho , A. -L. Y. Gschrey , C. J. A. P. Martins