Miguel Angel Javaloyes

On the interplay between Lorentzian Causality and Finsler metrics of Randers type

We obtain some results in both Lorentz and Finsler geometries, by using a correspondence between the conformal structure (Causality) of standard stationary spacetimes on

On the energy functional on Finsler manifolds and applications to stationary spacetimes

M=\R\times S

A note on the existence of standard splittings for conformally stationary spacetimes

and Randers metrics on

Morse theory of causal geodesics in a stationary spacetime via Morse theory of geodesics of a Finsler metric

S

Finsler metrics and relativistic spacetimes

. In particular, for stationary spacetimes, we give a simple characterization of when they are causally continuous or globally hyperbolic (including in the latter case, when

PENROSE'S SINGULARITY THEOREM IN A FINSLER SPACETIME

S

Relativistic particles with rigidity and torsion in D =3 spacetimes

is a Cauchy hypersurface), in terms of an associated Randers metric. Consequences for the computability of Cauchy developments are also derived. Causality suggests that the role of completeness in many results of Riemannian Geometry (geodesic connectedness by minimizing geodesics, Bonnet-Myers, Synge theorems) is played, in Finslerian Geometry, by the compactness of symmetrized closed balls. Moreover, under this condition we show that for any Randers metric there exists another Randers metric with the same pregeodesics and geodesically complete. Even more, results on the differentiability of Cauchy horizons in spacetimes yield consequences for the differentiability of the Randers distance to a subset, and vice versa.

GEODESICS AND JACOBI FIELDS OF PSEUDO-FINSLER MANIFOLDS

In this paper we first study some global properties of the energy functional on a non-reversible Finsler manifold. In particular we present a fully detailed proof of the Palais–Smale condition under the completeness of the Finsler metric. Moreover, we define a Finsler metric of Randers type, which we call Fermat metric, associated to a conformally standard stationary spacetime. We shall study the influence of the Fermat metric on the causal properties of the spacetime, mainly the global hyperbolicity. Moreover, we study the relations between the energy functional of the Fermat metric and the Fermat principle for the light rays in the spacetime. This allows one to obtain existence and multiplicity results for light rays, using the Finsler theory. Finally the case of timelike geodesics with fixed energy is considered.

Chern connection of a pseudo-Finsler metric as a family of affine connections

Let (M, g) be a spacetime which admits a complete timelike conformal Killing vector field K. We prove that (M, g) splits globally as a standard conformastationary spacetime with respect to K if and only if (M, g) is distinguishing (and, thus causally continuous). Causal but non-distinguishing spacetimes with complete stationary vector fields are also exhibited. For the proof, the recently solved “folk problems” on smoothability of time functions (moreover, the existence of a temporal function) are used.

Corrigendum to ``Chern connection of a pseudo-Finsler metric as a family of affine connections"

We show that the index of a lightlike geodesic in a conformally standard stationary spacetime is equal to the index of its spatial projection as a geodesic of a Finsler metric associated to the spacetime. Moreover we obtain the Morse relations of lightlike geodesics connecting a point to an integral line of the standard timelike Killing vector field by using Morse theory on the associated Finsler manifold. To this end, we prove a splitting lemma for the energy functional of a Finsler metric. Finally, we show that the reduction to Morse theory of a Finsler manifold can be done also for timelike geodesics.