Results 51 to 60 of about 13,985 (193)

A Re‐Examination of Foundational Elements of Cosmology

Fortschritte der Physik, Volume 74, Issue 3, March 2026.
ABSTRACT This paper undertakes a conceptual re‐examination of several foundational elements of cosmology through the lens of spacetime symmetries. A new derivation of the Friedmann–Lemaître–Robertson–Walker metric is obtained by a careful conceptual examination of rotations and translations on generic manifolds, followed by solving the rotational and ...
Lavinia Heisenberg
wiley   +1 more source

On Pseudospherical Smarandache Curves in Minkowski 3-Space

Journal of Applied Mathematics, 2014
In this paper we define nonnull and null pseudospherical Smarandache curves according to the Sabban frame of a spacelike curve lying on pseudosphere in Minkowski 3-space. We obtain the geodesic curvature and the expressions for the Sabban frame’s vectors
Esra Betul Koc Ozturk, Ufuk Ozturk, Kazim Ilarslan, Emilija Nešović   +3 more
doaj   +1 more source

A Morse-theoretical analysis of gravitational lensing by a Kerr-Newman black hole

, 2005
Consider, in the domain of outer communication of a Kerr-Newman black hole, a point (observation event) and a timelike curve (worldline of light source).
Abramowicz M. A., Chandrasekhar S., Frankel T., Giannoni F., Kozlowski M., Masiello A., Misner C., O’Neill B., Volker Perlick, Wolfgang Hasse   +9 more
core   +1 more source

Causal continuity in degenerate spacetimes [PDF]

, 1999
A change of spatial topology in a causal, compact spacetime cannot occur when the metric is globally Lorentzian. One can however construct a causal metric from a Riemannian metric and a Morse function on the background cobordism manifold, which is ...
, A Borde, Anderson A, Borde A, Carlip S, Carlip S, Dowker H F, Dowker H F, Dowker H F, Dowker H F, Geroch R P, Geroch R P, Gibbons G W, H F Dowker, Harris S G, Hawking S W, Hawking S W, Horowitz G T, Kronheimer E H, Louko J, Louko J, Louko J, Louko J, Manogue C A, Milnor J W, Milnor J W, Penrose R, R D Sorkin, R S Garcia, S Surya, Sorkin R D, Sorkin R D, Sorkin R D, Sorkin R D, Vilenkin A, Yodzis P   +35 more
core   +3 more sources

Axion Black Hole Solution in Non‐Metricity Gravity

Fortschritte der Physik, Volume 74, Issue 2, February 2026.
Abstract A static, spherically symmetric black hole solution in symmetric teleparallel (non‐metricity) gravity sourced by an axion field is constructed. Starting from the modified field equations, exact configurations are obtained characterized by the mass M$M$ and an axion–geometry coupling β$\beta$, with temporal metric function A(r)=1−2Mr+βr$A(r)=1-\
A. Eid, G.G.L. Nashed
wiley   +1 more source

Warp drives and closed timelike curves

Classical and Quantum Gravity
Abstract It is commonly accepted that superluminal travel may be used to facilitate time travel. This is a purely special-relativistic argument, using the fact that for observers in two frames of reference, separated by a spacelike interval, the non-causal (spacelike) future of one observer includes part of the causal past of the other ...
Barak Shoshany, Ben Snodgrass
openaire   +2 more sources

Relativity and Singularities - A Short Introduction for Mathematicians [PDF]

, 2005
We summarize the main ideas of General Relativity and Lorentzian geometry, leading to a proof of the simplest of the celebrated Hawking-Penrose singularity theorems.
Natario, Jose
core   +5 more sources

Rigidity of anti‐de Sitter (2+1)‐spacetimes with convex boundary near the Fuchsian locus

Journal of the London Mathematical Society, Volume 113, Issue 2, February 2026.
Abstract We prove that globally hyperbolic compact anti‐de Sitter (2+1)‐spacetimes with a strictly convex spacelike boundary that is either smooth or polyhedral and whose holonomy is close to Fuchsian are determined by the induced metric on the boundary.
Roman Prosanov, Jean‐Marc Schlenker
wiley   +1 more source

DUAL TIMELIKE NORMAL AND DUAL TIMELIKE SPHERICAL CURVES IN DUAL MINKOWSKI SPACE

Süleyman Demirel Üniversitesi Fen-Edebiyat Fakültesi Fen Dergisi, 2009
: In this paper, we give characterizations of dual timelike normal and dual timelike spherical curves in the dual Minkowski 3-space and we show that every dual timelike normal curve is also a dual timelike spherical curve.
Mehmet ÖNDER
doaj  

Chronology protection in stationary three-dimensional spacetimes

, 2011
We study chronology protection in stationary, rotationally symmetric spacetimes in 2+1 dimensional gravity, focusing especially on the case of negative cosmological constant.
A Campoleoni, A Dabholkar, BS Kay, C Herdeiro, D Freedman, EK Boyda, GS Hall, J Brown, J Raeymaekers, J Raeymaekers, Joris Raeymaekers, K Gödel, L Dyson, M Bañados, M Caldarelli, M Lubo, M Mars, M Rooman, MM Caldarelli, MS Costa, N Drukker, R Bousso, S Deser, S Hawking, V Balasubramanian, WJ Stockum van   +25 more
core   +2 more sources