Zobrazeno 1 - 10
of 63
pro vyhledávání: '"Wylleman, Lode"'
An IDEAL characterization of a particular spacetime metric, $g_0$, consists of a set of tensorial equations $T[g] = 0$ arising from expressions constructed from the metric, $g$, its curvature tensor and its covariant derivatives and which are satisfi
Externí odkaz:
http://arxiv.org/abs/2407.18410
Autor:
Aadne, Matthew, Wylleman, Lode
The Kundt conjecture states that a Lorentzian manifold of arbitrary dimension which is not characterized by its scalar polynomial curvature invariants (SPIs) allows for a non-twisting, non-shearing and non-expanding (in short, Kundt) null congruence
Externí odkaz:
http://arxiv.org/abs/2202.00608
Publikováno v:
2019 Class. Quantum Grav. 36 235018
We consider the equivalence problem for cosmological models in four-dimensional gravity theories. A cosmological model is considered as a triple $(M, {\bf g},{\bf u})$ consisting of a spacetime $(M, {\bf g})$ and a preferred normalized time-like vect
Externí odkaz:
http://arxiv.org/abs/2007.15915
Publikováno v:
Class. Quantum Grav. 38 (2021) 165009
In electromagnetism, the concept of Poynting vector as measured by an observer is well known. A mathematical analogue in general relativity is the super-Poynting vector of the Weyl tensor. Observers for which the (super-)Poynting vector vanishes are
Externí odkaz:
http://arxiv.org/abs/2007.15384
Publikováno v:
Phys. Rev. D 104, 084081 (2021)
The curvature invariants have been subject of interest due to the debate concerning the notions of intrinsic/extrinsic frame-dragging, the use of the electromagnetic analogy in such classification, and the question of whether there is a fundamental d
Externí odkaz:
http://arxiv.org/abs/1603.03143
Autor:
Wylleman, Lode
Einstein spacetimes in 5d that are of genuine type II in the null alignment classification are considered. It is shown that the unique geodesic multiple Weyl aligned null direction (mWAND) cannot have an optical matrix of rank 1 or 3. This finalizes
Externí odkaz:
http://arxiv.org/abs/1511.02824
Autor:
Aeyels, Dirk, Wylleman, Lode
We consider networks of weakly pulse-coupled identical oscillators. In an effort to resolve a long-standing problem, we develop an analytic condition on the infinitesimal phase response curve (iPRC) for synchronized dynamic behaviour, extending the w
Externí odkaz:
http://arxiv.org/abs/1409.3515
Publikováno v:
Springer Proc.Phys. 157 (2014) 287-290
Recent results on purely electric (PE) or magnetic (PM) spacetimes in n dimensions are summarized. These include: Weyl types; diagonalizability; conditions under which direct (or warped) products are PE/PM.
Comment: 4 pages; short summary of (pa
Comment: 4 pages; short summary of (pa
Externí odkaz:
http://arxiv.org/abs/1301.3691
Autor:
Milson, Robert, Wylleman, Lode
Publikováno v:
CQG vol 30, 2013, 095004
We show that the equivalence problem for three-dimensional Lorentzian manifolds requires at most the fifth covariant derivative of the curvature tensor. We prove that this bound is sharp by exhibiting a class of 3D Lorentzian manifolds which realize
Externí odkaz:
http://arxiv.org/abs/1210.6920
Autor:
Wylleman, Lode
Publikováno v:
J. Phys.: Conf. Ser. 229 (2010) 012073
It is pointed out that physically meaningful aligned Petrov type D perfect fluid space-times with constant zero-order Riemann invariants are either the homogeneous solutions found by G\"{o}del (isotropic case) and Farnsworth and Kerr (anisotropic cas
Externí odkaz:
http://arxiv.org/abs/1204.1362