Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.2/2336
Título: Orientation matters for NIMreps
Autor: Sousa, Nuno
Schellekens, Adrianus
Palavras-chave: Física
Teoria de cordas
Physics
String theory
Data: 2003
Editora: Elsevier Science B.V.
Citação: Sousa, Nuno; Schellekens, Adrianus - Orientation matters for NIMreps [Em linha]. "Nuclear Physics B". ISSN 0550-3213. Vol. 653, Nº 3 (March 2003), p. 339-368
Resumo: The problem of finding boundary states in CFT, often rephrased in terms of “NIMreps” of the fusion algebra, has a natural extension to CFT on non-orientable surfaces. This provides extra information that turns out to be quite useful to give the proper interpretation to a NIMrep. We illustrate this with several examples. This includes a rather detailed discussion of the interesting case of the simple current extension of A2 level 9, which is already known to have a rich structure. This structure can be disentangled completely using orientation information. In particular we find here and in other cases examples of diagonal modular invariants that do not admit a NIMrep, suggesting that there does not exist a corresponding CFT. We obtain the complete set of NIMreps (plus Moebius and Klein bottle coefficients) for many exceptional modular invariants of WZW models, and find an explanation for the occurrence of more than one NIMrep in certain cases. We also (re)consider the underlying formalism, emphasizing the distinction between oriented and unoriented string annulus amplitudes, and the origin of orientation-dependent degeneracy matrices in the latter.
Peer review: yes
URI: http://hdl.handle.net/10400.2/2336
ISSN: 0550-3213
Versão do Editor: http://dx.doi.org/10.1016/S0550-3213(02)01124-0
Aparece nas colecções:Ciências e Tecnologia - Artigos em revistas internacionais / Papers in international journals

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