Results 71 to 80 of about 108,791 (169)

Numerical Approaches to Spacetime Singularities

Living Reviews in Relativity, 2002
This Living Review updates a previous version which is itself an update of a review article. Numerical exploration of the properties of singularities could, in principle, yield detailed understanding of their nature in physically realistic cases ...
Berger Beverly K.
doaj  

Rigorous reconstruction of gluon propagator in the presence of complex singularities

SciPost Physics Proceedings, 2022
It has been suggested that the Landau-gauge gluon propagator has complex singularities, which invalidates the K\"all\'en-Lehmann spectral representation.
Yui Hayashi, Kei-Ichi Kondo
doaj   +1 more source

A Persisting Equivalence

Noûs, EarlyView.
ABSTRACT In several articles, McCall and Lowe have claimed that endurantism and perdurantism are “equivalent.” From this, they conclude that there is no fact of the matter as to whether we live in an endurantist world or in a perdurantist world. In this paper, I use the notion of Morita equivalence to show in which precise sense, McCall and Lowe's ...
Joshua Babic
wiley   +1 more source

Singular sources in Demiański–Newman spacetimes [PDF]

Classical and Quantum Gravity, 2006
The analysis of singular regions in the NUT solutions carried out in the recent paper (Manko and Ruiz, 2005 Class. Quantum Grav. 22, p.3555) is now extended to the Demianski-Newman vacuum and electrovacuum spacetimes. We show that the effect which produces the NUT parameter in a more general situation remains essentially the same as in the purely NUT ...
Manko, V. S., Martin, J., Ruiz, E.
openaire   +2 more sources

Covariant singularities in quantum field theory and quantum gravity

Nuclear Physics B, 2021
It is rather well-known that spacetime singularities are not covariant under field redefinitions. A manifestly covariant approach to singularities in classical gravity was proposed in [1].
Roberto Casadio, Alexander Kamenshchik, Iberê Kuntz   +2 more
doaj   +1 more source

What in the World Are 4D Shapes?

Noûs, EarlyView.
ABSTRACT It is often said that in special relativity, 4D shapes can be used to explain 3D shape projections onto frames of reference. Perdurantists have frequently used this as a motivation for their view of persistence. Despite this, philosophers never clearly state what 4D shapes are.
Jack Himelright, Sebastián Murgueitio Ramírez   +1 more
wiley   +1 more source

Complex Riemannian Spacetime and Singularity-Free Black Holes and Cosmology

Axioms
An approach is presented to address singularities in general relativity using a complex Riemannian spacetime extension. We demonstrate how this method can be applied to both black hole and cosmological singularities, specifically focusing on the ...
John W. Moffat
doaj   +1 more source

A Theory of the A‐Theory

Noûs, EarlyView.
ABSTRACT There is no precise characterization of the A‐ and B‐theories that has won a consensus in the literature. In this paper, we set out to provide clear formulations of these theories in the setting of higher‐order logic in what we call the operational framework.
Minjun Kang
wiley   +1 more source

Singularities and conjugate points in FLRW spacetimes [PDF]

General Relativity and Gravitation, 2017
Conjugate points play an important role in the proofs of the singularity theorems of Hawking and Penrose. We examine the relation between singularities and conjugate points in FLRW spacetimes with a singularity. In particular we prove a theorem that when a non-comoving, non-spacelike geodesic in a singular FLRW spacetime obeys conditions (39) and (40),
Huibert het Lam, Tomislav Prokopec
openaire   +4 more sources

Is science without spacetime possible? [PDF]

, 2012
Numerous approaches to a quantum theory of gravity posit fundamental ontologies that exclude spacetime, either partially or wholly. This situation raises deep questions about how such theories could relate to the empirical realm, since arguably only ...
Wuthrich, Christian, Huggett, Nick
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