Results 61 to 70 of about 58,187 (222)

Geometric inequivalence of metric and Palatini formulations of General Relativity

Physics Letters B, 2020
Projective invariance is a symmetry of the Palatini version of General Relativity which is not present in the metric formulation. The fact that the Riemann tensor changes nontrivially under projective transformations implies that, unlike in the usual ...
Cecilia Bejarano, Adria Delhom, Alejandro Jiménez-Cano, Gonzalo J. Olmo, Diego Rubiera-Garcia   +4 more
doaj   +1 more source

Generalized Chemical Model for Warm Dense Hydrogen: Ionization Potential Depression and Molecular Dissociation Shifts

Contributions to Plasma Physics, EarlyView.
ABSTRACT Warm dense matter (WDM) is a complex state, where quantum effects, thermal excitations, and strong interparticle correlations coexist. Understanding its microscopic composition and medium‐induced modifications of atomic and molecular properties is essential for planetary modeling, fusion research, and high‐energy‐density experiments.
L. T. Yerimbetova, Yu. V. Arkhipov, Ye. S. Mukhametkarimov, A. E. Davletov, I. M. Tkachenko   +4 more
wiley   +1 more source

Geodesic motion in the Kundt spacetimes and the character of envelope singularity

, 2004
We investigate geodesics in specific Kundt type N (or conformally flat) solutions to Einstein's equations. Components of the curvature tensor in parallelly transported tetrads are then explicitly evaluated and analyzed.
Baldwin O R, Barnes A, Belá? M Podolský J, Bi?ák J, Bi?ák J, Bi?ák J, Bondi H, Brdi?ka M, Brinkmann H W, Edgar S B, Edgar S B, Edgar S B, Ehlers J, Ellis G F R, García Díaz A, Griffiths J B, Griffiths J B, J Podolský, Koutras A, Kundt W, Kundt W, Levi-Civita T, M Belán, Nariai H, Ozsváth I, Podolský J, Podolský J, Podolský J, Podolský J, Pravda V, Robinson I, Siklos S, Skea J E F, Stephani H, Urbantke H, Van den Bergh N, Wils P   +36 more
core   +1 more source

Creep properties and constitutive model of diabase in deep water conveyance tunnels

Deep Underground Science and Engineering, EarlyView.
The axial and lateral creep characteristics of diabase were analyzed based on compression creep tests. The nonlinear viscoelastic‐plastic model capable of describing the whole creep process was established based on the fractional derivative and damage theories.
Zhigang Tao, Pengxiao Guan, Xiaojie Yang, Keyuan Liu, Mingjiu Cai, Hong Yang   +5 more
wiley   +1 more source

Maxwell-modified metric affine gravity

European Physical Journal C: Particles and Fields, 2021
We present a gauge formulation of the special affine algebra extended to include an antisymmetric tensorial generator belonging to the tensor representation of the special linear group.
Oktay Cebecioğlu, Salih Kibaroğlu
doaj   +1 more source

Riemann-Christoffel flows

, 2007
A geometric flow based in the Riemann-Christoffel curvature tensor that in two dimensions has some common features with the usual Ricci flow is presented.
Letelier, Patricio S.
core   +1 more source

Application of High‐Order Direct Flux Reconstruction and Stiffness‐Resilient Time Integration to Simulations of Idealized Atmospheric Flows

International Journal for Numerical Methods in Fluids, EarlyView.
The proposed work implements a direct flux reconstruction method for spatial discretization and a stiffness‐resilient exponential time integration method for temporal discretization on the cube‐sphere grid. A space‐time tensor formalism is employed to provide a general representation in any curvilinear coordinate system. This combination enables highly
Stéphane Gaudreault, Christopher Subich, Shoyon Panday, Martin Charron, Vincent Magnoux, Valentin Dallerit, Mayya Tokman   +6 more
wiley   +1 more source

On Almost C(α)-Manifold Satisfying Certain Curvature Conditions

Cumhuriyet Science Journal
This research article is about the geometry of the almost C(α)- manifold. Some important properties of the almost C(α)- manifold with respect to the W_3- curvature tensor, such as W_3-flat and W_3- semi-symmetry, are investigated.
Pakize Uygun, Tuğba Mert, Mehmet Atçeken   +2 more
doaj   +1 more source

Riemann curvature of a boosted spacetime geometry [PDF]

, 2014
The ultrarelativistic boosting procedure had been applied in the literature to map the metric of Schwarzschild-de Sitter spacetime into a metric describing de Sitter spacetime plus a shock-wave singularity located on a null hypersurface.
E. Battista, G. Esposito, P. Scudellaro, F. Tramontano   +3 more
semanticscholar   +1 more source

Revisiting PSF models: Unifying framework and high‐performance implementation

Journal of Microscopy, EarlyView.
Abstract Localisation microscopy often relies on detailed models of point‐spread functions. For applications such as deconvolution or PSF engineering, accurate models for light propagation in imaging systems with a high numerical aperture are required. Different models have been proposed based on 2D Fourier transforms or 1D Bessel integrals.
Yan Liu, Vasiliki Stergiopoulou, Jonathan Chuah, Eric Bezzam, Gert‐Jan Both, Michael Unser, Daniel Sage, Jonathan Dong   +7 more
wiley   +1 more source