# Cardy states as idempotents of fusion ring in string field theory

@article{Kishimoto2004CardySA, title={Cardy states as idempotents of fusion ring in string field theory}, author={I. Kishimoto and Y. Matsuo}, journal={Physics Letters B}, year={2004}, volume={590}, pages={303-308} }

With some assumptions, the algebra between Ishibashi states in string field theory can be reduced to a commutative ring. From this viewpoint, Cardy states can be identified with its idempotents. The algebra is identified with the fusion ring for the rational conformal field theory and the group ring for the orbifold. This observation supports our previous observation that the boundary states satisfy a universal idempotency relation under the closed string star product.

#### 8 Citations

Cardy states, factorization and idempotency in closed string field theory

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Abstract We show that boundary states in the generic on-shell background satisfy a universal nonlinear equation of closed string field theory. It generalizes our previous claim for the flat… Expand

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We generalize the idea of boundary states to open string channel. They describe the emission and absorption of the open string in the presence of intersecting D-branes. We study the algebra between… Expand

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We define BRST invariant observables in the OSp invariant closed string field theory for bosonic strings. We evaluate correlation functions of these observables and show that the S-matrix elements… Expand

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We construct solitonic states in the OSp invariant string field theory, which are BRST invariant in the leading order of regularization parameter. One can show that these solitonic states describe… Expand

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