T-duality across non-extremal horizons

After the paper discussion, Andriana Makridou will present the paper "T-duality across non-extremal horizons" (arXiV: 2401.00296) by M. Medevielle and T. Mohaupt.

"When applying T-duality to a generic, non-extreme Killing horizon, T-duality is spacelike on one side and timelike on the other. We show, using simple examples from four-dimensional Einstein-Maxwell theory, that the image of the horizon is a singularity which can be understood as an interface between two different T-dual theories and their solutions. Using an embedding into type-II string theory, we show that the singularity occurs when scalars reach the boundary of moduli space, resulting in a breakdown of the effective field theory due to the presence of tensionless strings."