Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Black-hole threshold solutions in stiff fluid collapse   Numerical studies of the gravitational collapse of a stiff (P=rho) fluid have
found the now familiar critical phenomena, namely scaling of the black hole
mass with a critical exponent and continuous self-similarity at the threshold
of black hole formation. Using the equivalence of an irrotational stiff fluid
to a massless scalar field, we construct the critical solution as a scalar
field solution by making a self-similarity ansatz. We find evidence that this
solution has exactly one growing perturbation mode; both the mode and the
critical exponent, gamma ~ 0.94, derived from its eigenvalue agree with those
measured in perfect fluid collapse simulations. We explain why this solution is
seen as a critical solution in stiff fluid collapse but not in scalar field
collapse, and conversely why the scalar field critical solution is not seen in
stiff fluid collapse, even though the two systems are locally equivalent.

23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th