Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Vacuum bubble collisions: from microphysics to gravitational waves   We comprehensively study the effects of bubble wall thickness and speed on
the gravitational wave emission spectrum of collisions of two vacuum bubbles.
We numerically simulate a large dynamical range, making use of symmetry to
reduce the dimensionality. The high-frequency slope of the gravitational wave
spectrum is shown to depend on the thickness of the bubble wall, becoming
steeper for thick-wall bubbles, in agreement with recent fully 3+1 dimensional
lattice simulations of many-bubble collisions. This dependence is present, even
for highly relativistic bubble wall collisions. We use the reduced
dimensionality as an opportunity to investigate dynamical phenomena which may
underlie the observed differences in the gravitational wave spectra. These
phenomena include `trapping', which occurs most for thin-wall bubbles, and
oscillations behind the bubble wall, which occur for thick-wall bubbles.

22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph