Integrable string models in terms of chiral invariants of groups.
Integral formulas for closed spacelike hypersurfaces in anti-de Sitter space
In this paper, we study closed -maximal spacelike hypersurfaces in anti-de Sitter space with two distinct principal curvatures and give some integral formulas about these hypersurfaces.
Is the geodesic hypothesis in general relativity falsifiable?
Kaluza-Klein or fibre bundles?
Killing's equations in dimension two and systems of finite type
A PDE system is said to be of finite type if all possible derivatives at some order can be solved for in terms lower order derivatives. An algorithm for determining whether a system of finite type has solutions is outlined. The results are then applied to the problem of characterizing symmetric linear connections in two dimensions that possess homogeneous linear and quadratic integrals of motions, that is, solving Killing's equations of degree one and two.
Kinematic geometry of triangles and the study of the three-body problem.
Lepage forms theory applied
In the presented paper we apply the theory of Lepage forms on jet prolongations of fibred manifold with one-dimensional base to the relativistic mechanics. Using this geometrical theory, we obtain and discuss some well-known conservation laws in their general form and apply them to a concrete physical example.
Les équations de Maxwell
Les résonances d'un trou noir de Schwarzschild
Lorentz-invariant quantum fields in the space-time tangent bundle.
Natural affinors on time-dependent Weil bundles
Nature of the central singularity in Szekeres models
The occurrence and nature of the central naked singularity in aspherical Szekeres models is investigated here, and the strength of the singularity is discussed. The implications for the cosmic censorship hypothesis are considered.
New results on de Sitter quantum field theory
Newton transformations on null hypersurfaces
Any rigged null hypersurface is provided with two shape operators: with respect to the rigging and the rigged vector fields respectively. The present paper deals with the Newton transformations built on both of them and establishes related curvature properties. The laters are used to derive necessary and sufficient conditions for higher-order umbilicity and maximality we introduced in passing, and develop general Minkowski-type formulas for the null hypersurface, supported by some physical models...
Noncommutative Lagrange mechanics.
Nonexistence of axially symmetric, stationary solution of Einstein vacuum equation with disconnected symmetric event horizon.
Nonexistence of Petrov type III space-times on which Weyl's neutrino equation or Maxwell's equations satisfy Huygens' principle
Non-Hermitian quantum systems and time-optimal quantum evolution.
Non-Riemannian gravitational interactions
Recent developments in theories of non-Riemannian gravitational interactions are outlined. The question of the motion of a fluid in the presence of torsion and metric gradient fields is approached in terms of the divergence of the Einstein tensor associated with a general connection. In the absence of matter the variational equations associated with a broad class of actions involving non-Riemannian fields give rise to an Einstein-Proca system associated with the standard Levi-Civita connection.
Null geodesic congruences, asymptotically-flat spacetimes and their physical interpretation.