Results 41 to 50 of about 77,425 (318)

Perturbative solutions of the f(R)-theory of gravity in a central gravitational field and some applications

European Physical Journal C: Particles and Fields, 2018
Exact solutions of an f(R) -theory (of gravity) in a static central (gravitational) field have been studied in the literature quite well, but, to find and study exact solutions in the case of a non-static central field are not easy at all.
Nguyen Anh Ky, Pham Van Ky, Nguyen Thi Hong Van   +2 more
doaj   +1 more source

Exploring the solitary wave solutions of Einstein's vacuum field equation in the context of ambitious experiments and space missions

Alexandria Engineering Journal, 2023
In the present work, Einstein's vacuum field equation is investigated analytically to explore the solitary wave solutions. This equation arises in mathematical physics, having meaningful applications in the general theory of relativity.
Mustafa Inc, Muhammad S. Iqbal, Muhammad Z. Baber, Muhammad Qasim, Zafar Iqbal, Muhammad Akhtar Tarar, Ali Hasan Ali   +6 more
doaj   +1 more source

Clouds of strings in third-order Lovelock gravity

, 2014
Lovelock theory is a natural extension of the Einstein theory of general relativity to higher dimensions in which the first and second orders correspond, respectively, to general relativity and Einstein-Gauss-Bonnet gravity.
Ghosh, Sushant G., Maharaj, Sunil D., Papnoi, Uma   +2 more
core   +1 more source

Universe Models with a Variable Cosmological "Constant" and a "Big Bounce" [PDF]

, 2001
We present a rich class of exact solutions which contains radiation-dominated and matter-dominated models for the early and late universe. They include a variable cosmological ``constant'' which is derived from a higher dimension and manifests itself in ...
Hongya Liu, Liu H., Paul S. Wesson
core   +2 more sources

Planar solutions of higher-spin theory. Part I. Free field level

Journal of High Energy Physics, 2021
Many black hole solutions of General Relativity are known to be linearly exact. This opens a way to study them in gauge theories that apart from gravity contain fields of higher spin s > 2.
V. E. Didenko, A. V. Korybut
doaj   +1 more source

The physical meaning of the "boost-rotation symmetric" solutions within the general interpretation of Einstein's theory of gravitation

, 2005
The answer to the question, what physical meaning should be attributed to the so-called boost-rotation symmetric exact solutions to the field equations of general relativity, is provided within the general interpretation scheme for the ``theories of ...
A. Einstein, A. Einstein, Dierck-Ekkehard Liebscher, E. Kretschmann, G. Beck, G. Ricci, G. Szekeres, H. Bondi, H. Weyl, H. Weyl, J. Bičák, J. Bičák, J. Bičák, J.L. Synge, Luigi Mihich, M.D. Kruskal, Ph. Frank, R. Bach, Salvatore Antoci, T. Levi-Civita, W. Israel, W.B. Bonnor, W.B. Bonnor, W.B. Bonnor, W.B. Bonnor   +24 more
core   +1 more source

Exact Static Cylindrical Solution to Conformal Weyl Gravity [PDF]

, 2012
We present the exact exterior solution for a static and neutral cylindrically symmetric source in locally conformal invariant Weyl gravity. As a special case the general relativity analogue still can be attained, however only as a sub-family of solutions.
B. S. DeWitt, Jackson Levi Said, Joseph Sultana, Kristian Zarb Adami   +3 more
core   +2 more sources

Axially symmetric solutions in f(R)-gravity

, 2010
Axially symmetric solutions for f (R)-gravity can be derived starting from exact spherically sym- metric solutions achieved by Noether symmetries. The method takes advantage of a complex coordi- nate transformation previously developed by Newman and ...
Arnold V I, Arturo Stabile, Barrow J D, Capozziello S, Capozziello S, Capozziello S, Capozziello S, Capozziello S, Carloni S, Chandrasekhar S, D'Inverno R, Faraoni V, Ince E L, Mariafelicia De Laurentis, Marmo G, McManus D, Misner Ch W, Olmo G J, Salvatore Capozziello   +18 more
core   +2 more sources

Infection Models for Pine Wilt Disease on the Basis of Vector Behaviors

Population Ecology, EarlyView.
Infection models for pine wilt disease without vector density were built to estimate the transmission coefficient of the pathogenic nematode. The models successfully simulated the annual change in the density of infected trees for four pine stands. ABSTRACT Pine wilt disease is caused by the pinewood nematode (Bursaphelenchus xylophilus Steiner et ...
Katsumi Togashi
wiley   +1 more source

Minisuperspace Examples of Quantization Using Canonical Variables of the Ashtekar Type: Structure and Solutions

, 1995
The Ashtekar variables have been use to find a number of exact solutions in quantum gravity and quantum cosmology. We investigate the origin of these solutions in the context of a number of canonical transformations (both complex and real) of the basic ...
A. Ashtekar, A. Lafiti, A. Taub, C. Misner, H. Kodama, H. Kodama, I. E. Segal, J. F. Barbero, J. Fernando Barbero, J. Hartle, K. Kuchař, M. Ryan, Michael P. Ryan, O. Obregon, P. D'Eath, R. Graham, V. Bargmann, V. Belinskii, V. Moncrief   +18 more
core   +1 more source