Non-geometric backgrounds based on topological interfaces

Abstract

Abstract:We study simple models of the world-sheet CFTs describing non-geometric backgrounds based on the topological interfaces, the 'gluing condition' of which imposes T-duality-or analogous twists. To be more specific, we start with the torus partition function on a target spacewith rather general values of radii. The fiber CFT is defined by inserting the twist operators consisting of the topological interfaces which lie along the cycles of the world-sheet torus according to the winding numbers of the base circle. We construct the partition functions involving such duality twists. The modular invariance is achieved straightforwardly, whereas 'unitarization' is generically necessary to maintain the unitarity. We demonstrate it in the case of the equal fiber radii. The resultant models are closely related to the CFTs with the discrete torsion. The unitarization is also physically interpreted as multiple insertions of the twist/interface operators along various directions.

Non-supersymmetric asymmetric orbifolds with vanishing cosmological constant

“…[12]. A challenging direction in this respect, and along [15], would be to construct such vacua based on the generalized orbifolds through the topological interfaces, which are wrapped around the cycles of the world-sheet torus in correlation JHEP02 (2016)184 with the shift operators. 13 The point here would be how to organize the world-sheet chiral sectors depending on the winding numbers along the Scherk-Schwarz like circle, so that the bose-fermi cancellation does occur.…”

“…These types of string vacua have been studied based on the world-sheet CFT e.g. in [9][10][11][12][13][14][15][16]. 1 In this paper, we study type II string vacua defined by torus compactifications twisted by T-duality transformations in the above sense.…”

“…We refer to such CFTs as "generalized orbifold" CFTs, according to [37][38][39] where such CFTs are studied in the context of the topological conformal interfaces [40][41][42][43]. An application to non-geometric backgrounds has been discussed in [15]. Even though the twists are not necessarily by the full symmetries, the transformations may need to commute with the Hamiltonian, since the position of the twist operators matters otherwise.…”

“…The lightest excitations appear in the sectors of w = ±2, the conformal weights of which read 15) with the KK momenta n ∈ Z + …”

More on non-supersymmetric asymmetric orbifolds with vanishing cosmological constant

“…These types of non-geometric backgrounds have been studied by the approach of world-sheet CFT e.g. in [25][26][27][28][29][30][31][32]. Now, in this paper, we would like to explore a variety of non-SUSY string vacua of this type.…”