HEP Colloquia 2022

by Dr Roberta Angius (Instituto de Física Teórica, Madrid)

Monday 9 Jan 2023, 14:30 → 16:30 Europe/Rome

Aula C (Department of Physics)

Dynamical Cobordisms and the beginning of time

The main goal of Swampland Program is to study of the constraints on the Effective Field Theories (EFT) to be compatible with Quantum Gravity.
In this talk, I will focus on the Cobordism conjecture. At topological level it states that the whole set of different backgrounds in Quantum Gravity is completely networked through interpolating configura- tions. This includes end-of-the world configurations in which the theory space-time simply ends at a co-dimension 1 boundary, defining a Cobordism to Nothing.

I will describe dynamical realizations of such configurations following an effective field theory approach in String Theory. The Cobordism appears as space-time running solutions of a d-dimensional Einstein- gravity theory coupled to scalars and showing a Singularity at finite distance in space-time at which scalars go off to infinite. Following this approach, it seems natural to identify the source of the singu- larity with an extended object, an End of The World (ETW) brane, localized at the boundary of the running direction.

I will provide a Local Universal description of the theory in the regime near the ETW-brane, where the solutions simplify dramatically and the dynamics is controlled just by one critical exponent. Specializing this treatment to time-dependent solutions, I will consider a Timelike Linear Dilaton back- ground in Supercritical Bosonic string theory and I will express it as time-dependent Dynamical Cobor- dism with a space-like singularity at the beginning of time characterized by a precise critical exponent. Finally, I will propose a resolution for such singularity in terms of a Tachyon condensation phase.

 

Based on:

[1] R. Angius, J. Calderón-Infante, M. Delgado, J. Huertas and A.M. Uranga, At the end of the world: Local Dynamical Cobordism, JHEP 06 (2022) 142 [arXiv:2203.11240]
[2] R. Angius,M. Delgado and A.M. Uranga, Dynamical Cobordism and the beginning of time: supercritical strings and tachyon condensation, JHEP 08 (2022) 285 [arXiv:2207.13108]