Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bulk Viscosity and Cavitation in Boost-Invariant Hydrodynamic Expansion   We solve second order relativistic hydrodynamics equations for a
boost-invariant 1+1-dimensional expanding fluid with an equation of state taken
from lattice calculations of the thermodynamics of strongly coupled quark-gluon
plasma. We investigate the dependence of the energy density as a function of
proper time on the values of the shear viscosity, the bulk viscosity, and
second order coefficients, confirming that large changes in the values of the
latter have negligible effects. Varying the shear viscosity between zero and a
few times s/(4 pi), with s the entropy density, has significant effects, as
expected based on other studies. Introducing a nonzero bulk viscosity also has
significant effects. In fact, if the bulk viscosity peaks near the crossover
temperature Tc to the degree indicated by recent lattice calculations in QCD
without quarks, it can make the fluid cavitate -- falling apart into droplets.
It is interesting to see a hydrodynamic calculation predicting its own
breakdown, via cavitation, at the temperatures where hadronization is thought
to occur in ultrarelativistic heavy ion collisions.

21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an