Semi-local cosmic strings and the cosmological constant problem
We study the cosmological constant problem in a three-dimensional N = 2 supergravity theory with gauge group SU (2)<sub>global</sub> × U (1)<sub>local</sub>. The model we consider is known to admit string-like configurations, the so-called semi-local cosmic strings. We show t...
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 1997 |
| País: | Argentina |
| Institución: | Universidad Nacional de La Plata |
| Repositorio: | SEDICI (UNLP) |
| Idioma: | inglés |
| OAI Identifier: | oai:sedici.unlp.edu.ar:10915/122981 |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/122981 |
| Access Level: | acceso abierto |
| Palabra clave: | Física Ciencias Exactas Supersymmetry Gauge group Cosmic string Higgs boson Supergravity |
| Sumario: | We study the cosmological constant problem in a three-dimensional N = 2 supergravity theory with gauge group SU (2)<sub>global</sub> × U (1)<sub>local</sub>. 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. |
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