منابع مشابه
Discrete Torsion and WZW Orbifolds
We propose a geometrical interpretation for the discrete torsion appearing in the algebraic formulation of quotients of WZW models by discrete abelian subgroups. Part of the discrete torsion corresponds to the choice of action of the subgroup, yielding different quotient spaces. Another part corresponds to the set of different choices of connection for the H field in each of these spaces. The f...
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In this paper we make two observations related to discrete torsion. First, we observe that an old obscure degree of freedom (momentum/translation shifts) in (symmetric) string orbifolds is related to discrete torsion. We point out how our previous derivation of discrete torsion from orbifold group actions on B fields includes these momentum lattice shift phases, and discuss how they are realize...
متن کاملOn Orbifolds with Discrete Torsion
We consider the interpretation in classical geometry of conformal field theories constructed from orbifolds with discrete torsion. In examples we can analyze, these spacetimes contain " stringy regions " that from a classical point of view are singularities that are to be neither resolved nor blown up. Some of these models also give particularly simple and clear examples of mirror symmetry.
متن کاملBPS branes in discrete torsion orbifolds
We investigate D-branes in a Z3 × Z3 orbifold with discrete torsion. For this class of orbifolds the only known objects which couple to twisted RR potentials have been non-BPS branes. By using more general gluing conditions we construct here a D-brane which is BPS and couples to RR potentials in the twisted and in the untwisted sectors. ∗ [email protected]
متن کاملD-branes on Orbifolds with Discrete Torsion And Topological Obstruction
We find the orbifold analog of the topological relation recently found by Freed and Witten which restricts the allowed D-brane configurations of Type II vacua with a topologically non-trivial flat B-field. The result relies in Douglas proposal – which we derive from worldsheet consistency conditions – of embedding projective representations on open string Chan-Paton factors when considering orb...
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ژورنال
عنوان ژورنال: Physics Letters B
سال: 1989
ISSN: 0370-2693
DOI: 10.1016/0370-2693(89)90864-2