Semi-local cosmic strings and the cosmological constant problem

• Autores: Edelstein Glaubach, José Daniel
• Año de publicación: 1997
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Física; Ciencias Exactas; Supersymmetry; Gauge group; Cosmic string; Higgs boson; Supergravity
• Institución: Universidad Nacional de La Plata

We study the cosmological constant problem in a three-dimensional N = 2 supergravity theory with gauge group SU (2)_global × U (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 solitonic 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 Bogomol'nyi bound, as a consequence of an Aharonov-Bohmlike 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.
Facultad de Ciencias Exactas