27 research outputs found
Isotropization of non-diagonal Bianchi I spacetimes with collisionless matter at late times assuming small data
Assuming that the space-time is close to isotropic in the sense that the
shear parameter is small and that the maximal velocity of the particles is
bounded, we have been able to show that for non-diagonal Bianchi I-symmetric
spacetimes with collisionless matter the asymptotic behaviour at late times is
close to the special case of dust. We also have been able to show that all the
Kasner exponents converge to 1/3 and an asymptotic expression for the induced
metric has been obtained. The key was a bootstrap argument.Comment: V3 18 p. 3 fig. typos corrected, conclusions part extended,
references added. To appear in Classical and Quantum Gravit
Future non-linear stability for solutions of the Einstein-Vlasov system of Bianchi types II and VI
In a recent paper arXiv:1208.4231 we have treated the future non-linear
stability for reflection symmetric solutions of the Einstein-Vlasov system of
Bianchi types II and VI. We have been able now to remove the reflection
symmetry assumption, thus treating the non-diagonal case. Apart from the
increasing complexity the methods have been essentially the same as in the
diagonal case, showing that they are thus quite powerful.
Here the challenge was to put the equations in a form that permits the use of
the previous results. We are able to conclude that after a possible basis
change the future of the non-diagonal spacetimes in consideration is
asymptotically diagonal.Comment: 18 page
Polarized Electrogowdy spacetimes censored
A sketch of the proof of strong cosmic censorship is presented for a class of
solutions of the Einstein-Maxwell equations, those with polarized Gowdy
symmetry. A key element of the argument is the observation that by means of a
suitable choice of variables the central equations in this problem can be
written in a form where they are identical to the central equations for general
(i.e. non-polarized) vacuum Gowdy spacetimes. Using this it is seen that the
results of Ringstr\"{o}m on strong cosmic censorship in the vacuum case have
implications for the Einstein-Maxwell case. Working out the geometrical meaning
of these analytical results leads to the main conclusion.Comment: 6 pages, submitted to the conference proceedings of "Spanish
relativity meeting 2009
The electromagnetic spike solutions
The aim of this paper is to use the existing relation between polarized
electromagnetic Gowdy spacetimes and vacuum Gowdy spacetimes to find explicit
solutions for electromagnetic spikes by a procedure which has been developed by
one of the authors for gravitational spikes. We present new inhomogeneous
solutions which we call the EME and MEM electromagnetic spike solutions.Comment: V3: 13 pages and 4 figures. No change in main result. Title and names
of the solutions changed to make their physical interpretation more clea
Isotropization of solutions of the Einstein-Vlasov system with Bianchi V symmetry
Using the methods developed for different Bianchi class A cosmological models
we treat the simplest Bianchi class B model, namely Bianchi type V. The future
non-linear stability for solutions of the Einstein-Vlasov system is
demonstrated and it is shown that these solutions are asymptotically stable to
the Milne solution. Within the isotropic solutions of the Einstein-Vlasov
system the spatially flat Friedmann solution is unstable within this class, and
expanding models tend also to the Milne solution.Comment: V3: 18 pages. Typos fixed. Matches published version. arXiv admin
note: substantial text overlap with arXiv:1208.4231, arXiv:1208.615