Juan Fernando Angel Ramelli

, ágúst 22, 2019

PhD midway evaluation

Fyrirlesari: Juan Fernando Angel Ramelli, HÍ

Titill: Entanglement entropy of the quantum Lifshitz model

Staðsetning: A-050
Tími: Þriðjudag 27.ágúst kl. 09:00

Ágrip:

The quantum Lifshitz model (QLM) is a toy model used for studying scale invariant systems in which time and space scale on different footing. This type of behavior occurs, for example, in the context of critical phenomena. Entanglement entropy is a purely quantum measure of correlation between subsystems. It is a useful theoretical probe, as it encodes certain universal properties of critical models. I review the QLM as well as its generalization to higher dimensions, and show how to construct its excited states on compact manifolds. Through careful application of the replica method, I demonstrate that analytic results can be obtained for the entanglement entropy of both its ground state and its excited states.

Mohab Abou Zeid

, ágúst 20, 2019

Math Phys seminar

Fyrirlesari: Mohab Abou Zeid, Imperial College London

Titill: T-duality in (2,1) superspace and SKT geometry

Staðsetning: VR-II, V-156
Tími: Föstudag 23.ágúst kl. 14:00

Ágrip:

I will explain our recent derivation of the T-duality transformation rules for two-dimensional (2,1) supersymmetric sigma-models in (2,1) superspace. To this end I will first review the gauging of sigma-models in (2,1) superspace and present a new manifestly real and geometric expression for the gauged action. I will  also discuss the obstructions to gauging (2,1) sigma-models and show that the obstructions to (2,1) T-duality are considerably weaker than the obstructions to gauging. Our complexified T-duality transformations are equivalent to the usual Buscher duality transformations (including an important refinement) together with diffeomorphisms. Time permitting, I will mention some possible applications of our results.

Ro Jefferson

, ágúst 20, 2019

Math Phys seminar

Fyrirlesari: Ro Jefferson, Albert Einstein Institute Potsdam

Titill: Black hole interiors and modular inclusions

Staðsetning: VR-II, V-156
Tími: Fimmtudag 22.ágúst kl. 14:00

Ágrip:

We show how the traversable wormhole induced by a double-trace deformation of the thermofield double state can be understood as a modular inclusion of the algebras of exterior operators. The effect of this deformation is the creation of a new region of spacetime deep in the bulk, corresponding to a non-trivial center between the left and right algebras. This set-up provides a precise framework for investigating how black hole interiors are encoded in the CFT. In particular, we use modular theory to demonstrate that state dependence is an inevitable feature of any attempt to represent operators behind the horizon. Building on this geometrical structure, we propose that modular inclusions may provide a more precise means of investigating the nascent relationship between entanglement and geometry in the context of the emergent spacetime paradigm.