Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tunnelling with Bianchi IX Instantons   Within the context of finding the initial conditions of the universe we
consider gravitational instantons falling into the Bianchi IX classification.
That is, a Euclidean four-manifold with a metric that satisfies Einstein's
equations with an induced metric on S^3 submanifolds that is homogeneous but
anisotropic. As well as finding regular solutions to the field equations with a
tunnelling scalar field, we also look at the case of singular instantons with a
view to applying the results to generic potentials. The study is in agreement
with the prejudice that instantons with higher symmetry have a lower Euclidean
action, even when we consider the singular class of solutions. It is also found
that the Euclidean action can diverge for simple potentials, showing that the
Hawking Turok instanton had finite action owing to its symmetry.

11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ