Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ricci-Flat Branes   Up to overall harmonic factors, the D8-brane solution of the massive type IIA
supergravity theory is the product of nine-dimensional Minkowski space (the
worldvolume) with the real line (the transverse space). We show that the
equations of motion allow for the worldvolume metric to be generalised to an
arbitrary Ricci-flat one. If this nine-dimensional Ricci-flat manifold admits
Killing spinors, then the resulting solutions are supersymmetric and satisfy
the usual Bogomol'nyi bound, although they preserve fewer than the usual one
half of the supersymmetries. We describe the possible choices of such
manifolds, elaborating on the connection between the existence of Killing
spinors and the self-duality condition on the curvature two-form. Since the
D8-brane is a domain wall in ten dimensions, we are led to consider the general
case: domain walls in any supergravity theory. Similar considerations hold here
also. Moreover, it is shown that the worldvolume of any magnetic brane --- of
which the domain walls are a specific example --- can be generalised in
precisely the same way. The general class of supersymmetric solutions have
gravitational instantons as their spatial sections. Some mention is made of the
worldvolume solitons of such branes.

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The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: chao-dyn
2
The categories of this paper are: math
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
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The categories of this paper are: quant-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-ex
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The categories of this paper are: solv-int