Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Critical Collapse of Collisionless Matter in Spherical Symmetry   We perform a numerical study of the critical regime for the general
relativistic collapse of collisionless matter in spherical symmetry. The
evolution of the matter is given by the Vlasov equation (or Boltzmann equation)
and the geometry by Einstein's equations. This system of coupled differential
equations is solved using a particle-mesh (PM) method. This method approximates
the distribution function which describes the matter in phase space with a set
of particles moving along the characteristics of the Vlasov equation. The
individual particles are allowed to have angular momentum different from zero
but the total angular momentum has to be zero to retain spherical symmetry.
  In accord wih previous work by Rein, Rendall and Schaeffer, our results give
some indications that the critical behaviour in this model is of Type I (the
smallest black hole in each family has a finite mass). For the families of
initial data that we have studied it seems that in the critical regime the
solution is a static spacetime with non-zero radial momentum for the individual
particles. We have also found evidence for scaling laws for the time that the
critical solutions spend in the critical regime.

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The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics