Results 91 to 100 of about 74,681 (258)

What Is Temperature? Modern Outlook on the Concept of Temperature

Entropy, 2020
The meaning and evolution of the notion of “temperature” (which is a key concept for the condensed and gaseous matter theories) are addressed from different points of view.
Edward Bormashenko
doaj   +1 more source

Flat Cosmology with Coupled Matter and Dark Energies

, 2007
Three models of a flat universe of coupled matter and dark energies with different low-redshift parameterizations of the dark energy equation of state are considered.
A.-M. M. Abdel-Rahman, Abdel-Rahman A.-M. M., Baccigalupi C., Chiba T., Dabrowski Y., Frey S., Gurvits L. I., Ihab F. Riad, Jackson J. C., Jackson J. C., Lima J. A. S., Shklovskii I. S., Shklovskii I. S., Stepanas P. G., Ubachukwu A. A., Ubachukwu A. A., Wetterich C.   +16 more
core   +2 more sources

Global Anisotropies of ΩΛ

The Astrophysical Journal
An analysis of the cosmological constant Ω _Λ fitted to subsamples of the Pantheon+ Type Ia supernova sample spanning 2 π steradians for a grid of 432 pole positions covering the whole sky reveals two large-scale asymmetries.
Alejandro Clocchiatti, Ósmar Rodríguez, Ariel Órdenes Morales, Benjamin Cuevas-Tapia   +3 more
doaj   +1 more source

On the emergence of the $$\mathbf{\Lambda }$$ Λ CDM model from self-interacting Brans–Dicke theory in $$\mathbf{d= 5}$$ d=5

European Physical Journal C: Particles and Fields, 2018
We investigate whether a self-interacting Brans–Dicke theory in $$d=5$$ d=5 without matter and with a time-dependent metric can describe, after dimensional reduction to $$d=4$$ d=4 , the FLRW model with accelerated expansion and non-relativistic matter ...
Luz Marina Reyes, Santiago Esteban Perez Bergliaffa   +1 more
doaj   +1 more source

A theoretical prediction for the dipole in nearby distances using cosmography

The Open Journal of Astrophysics
Cosmography is a widely applied method to infer kinematics of the Universe at small cosmological scales while remaining agnostic about the theory of gravity at play.
Hayley J Macpherson, Asta Heinesen
doaj   +1 more source

The IXPE Science of Pulsars and Their Nebulae

Galaxies
Pulsars (PSRs) and Pulsar Wind Nebulae (PWNe) form some of the most interesting high-energy astrophysical systems. Their prominent synchrotron emission makes them ideal candidates for polarimetry.
Niccolò Bucciantini, Roger W. Romani, Fei Xie, Josephine Wong   +3 more
doaj   +1 more source

Cosmological comoving behavior of the configurational entropy

Physics Letters B, 2019
It has been shown that a functional dependence of the configurational entropy (CE) density exhibits a cosmological comoving behavior related to the scale parameter, a, of the FRW flat universe.
A.E. Bernardini, R. da Rocha
doaj   +1 more source

New accelerating cosmology without dark energy: the particle creation approach and the reduced relativistic gas

European Physical Journal C: Particles and Fields
The standard procedure to explain the accelerated expansion of the Universe is to assume the existence of an exotic component with negative pressure, generically called dark energy.
P. W. R. Lima, J. A. S. Lima, J. F. Jesus   +2 more
doaj   +1 more source

Spinning Systems in Quantum Mechanics: An Overview and New Trends

Universe
The study of spinning systems plays a question of interest in several research branches in physics. It allows the understanding of simple classical mechanical systems but also provides us with tools to investigate a wide range of phenomena, from ...
E. Brito, Júlio E. Brandão, Márcio M. Cunha   +2 more
doaj   +1 more source

On the Perturbed Friedmann Equations in Newtonian Gauge

Universe
Based on Newtonian mechanics, in this article, we present a heuristic derivation of the Friedmann equations, providing an intuitive foundation for these fundamental relations in cosmology.
Jaume de Haro, Emilio Elizalde, Supriya Pan   +2 more
doaj   +1 more source