## Abstract

We study the mutual consistency of twisted boundary conditions in the coset conformal field theory G/H. We calculate the overlap of the twisted boundary states of G/H with the untwisted ones, and show that the twisted boundary states are consistently defined in the charge-conjugation modular invariant. The overlap of the twisted boundary states is expressed by the branching functions of a twisted affine Lie algebra. As a check of our argument, we study the diagonal coset theory so(2n)_{1}⊕so(2n)_{1}/so(2n) _{2}, which is equivalent to the orbifold S^{1}/ℤ _{2} at a particular radius. We construct the boundary states twisted by the automorphisms of the unextended Dynkin diagram of so(2n), and show their mutual consistency by identifying their counterpart in the orbifold. For the triality of so(8), the twisted states of the coset theory correspond to neither the Neumann nor the Dirichlet boundary states of the orbifold and yield conformal boundary states that preserve only the Virasoro algebra.

Original language | English |
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Pages (from-to) | 541-582 |

Number of pages | 42 |

Journal | Journal of High Energy Physics |

Volume | 7 |

Issue number | 4 |

DOIs | |

Publication status | Published - 2003 Apr 1 |

## Keywords

- Boundary Quantum Field Theory
- Conformal Field Models in String Theory
- Conformal and W Symmetry
- D-branes

## ASJC Scopus subject areas

- Nuclear and High Energy Physics