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arXiv · hep-th/9610163

Semi-local Cosmic Strings and the Cosmological Constant Problem

Jose Daniel Edelstein
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Abstract

We study the cosmological constant problem in a three-dimensional N=2 supergravity theory with gauge group SU[2]_{global}xU[1]_{local}. The model we consider is known to admit string-like configurations, the so-called semi-local cosmic strings. We show that the stability of these solutions is provided by supersymmetry through the existence of a lower bound for the energy, even though the manifold of the Higgs vacuum does not contain non-contractible loops. Charged Killing spinors do exist over configurations that saturate the Bogomolnyi bound, as a consequence of an Aharonov-Bohm-like effect. Nevertheless, there are no physical fermionic zero modes on these backgrounds. The exact vanishing of the cosmological constant does not imply, then, Bose-Fermi degeneracy. This provides a non-trivial example of the recent claim made by Witten on the vanishing of the cosmological constant in three dimensions without unphysical degeneracies.

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Jose Daniel Edelstein. 1996-10-22. Semi-local Cosmic Strings and the Cosmological Constant Problem. https://doi.org/10.1016/s0370-2693(96)01385-8

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