Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Collisionless relaxation in gravitational systems: From violent
  relaxation to gravothermal collapse   Theory and simulations are used to study collisionless relaxation of a
gravitational $N$-body system. It is shown that when the initial one particle
distribution function satisfies the virial condition -- potential energy is
minus twice the kinetic energy -- the system quickly relaxes to a metastable
state described {\it quantitatively} by the Lynden-Bell distribution with a
cutoff. If the initial distribution function does not meet the virial
requirement, the system undergoes violent oscillations, resulting in a partial
evaporation of mass. The leftover particles phase separate into a core-halo
structure. The theory presented allows us to quantitatively predict the amount
and the distribution of mass left in the central core, without any adjustable
parameters. On a longer time scale $\tau_G \sim N$ collisionless relaxation
leads to a gravothermal collapse.

7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys