Results 111 to 120 of about 400,960 (288)

Third-order cosmological perturbations of zero-pressure multi-component fluids: Pure general relativistic nonlinear effects

, 2007
Present expansion stage of the universe is believed to be mainly governed by the cosmological constant, collisionless dark matter and baryonic matter. The latter two components are often modeled as zero-pressure fluids. In our previous work we have shown
Arnowitt R, Bardeen J M, Bernstein J, Bernstein J, Bonnor W B, Ehlers J, Ellis G F R, Ellis G F R, Hwang J, Hwang J, Hyerim Noh, Jai-chan Hwang, Lifshitz E M, Noh H, Peebles P J E, Vishniac E T   +15 more
core   +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

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

Sum-over-histories origin of the composition laws of relativistic quantum mechanics and quantum cosmology

, 1993
The scope of the paper has been broadened to include a more complete discussion of the following topics: The derivation of composition laws in quantum cosmology. The connection between the existence of a composition law in the sum over histories approach
A. Auerbach, C. Teitelboim, E. S. Fradkin, H. Ikemori, I. A. Batalin, J. A. Wheeler, J. B. Hartle, J. B. Hartle, J. B. Hartle, J. Govaerts, J. J. Halliwell, J. J. Halliwell, J. J. Halliwell, Jonathan J. Halliwell, K. Kuchař, L. I. Schiff, L. S. Schulman, L. Schulman, M. Henneaux, M. Kac, Miguel E. Ortiz, N. Yamada, R. H. Cameron, S. Coleman, S. Giddings   +24 more
core   +1 more source

GRAMSES: a new route to general relativistic N-body simulations in cosmology. Part II. Initial conditions [PDF]

, 2020
Cristian Barrera-Hinojosa, Baojiu Li
openalex   +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

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

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