Dynamical String Tension Theories with target space scale invariance, new braneworlds, modifying the swampland, explaining 4D and a new model for Dark Matter

by Eduardo Guendelman

BGU

at Particles and Fields Seminar

Mon, 19 May 2025, 14:00
Sacta-Rashi Building for Physics (54), room 207

Abstract

The string and brane tensions do not have to be put in by hand, they can be dynamically generated, as in the case when we formulate string and brane theories in the modified measure formalism. Then string and brane tensions appears, but as an additional dynamical degree of freedom. It can be seen however that these string or brane tensions are not universal, but rather each string and each brane generates its own tension, which can have a different value for each string or brane. We consider new background fields that can couple to these new types of extended objects, one of them, the “tension scalar” is capable of changing locally along the world sheet the value of the tension of the extended object. When many strings probing the same region of space are considered this tension scalar is constrained by the requirement of quantum conformal invariance. For the case of two strings probing the same region of space with different dynamically generated tensions, there are two different metrics, associated to the different strings, that have to satisfy vacuum Einstein’s equations and the consistency of these two Einstein’s equation determines the tension scalar. We discuss one of the examples where this solutions where the strings are confined by surfaces where the string tensions grow very big. The dynamical string tensions imply dynamical Planck scale and this can modify the swampland constraints. The demand that the effective low energy theory still respects the target space scale invariance, where gravity appears by integrating out the closed strings and open strings model matter leads to 4D. A new model of Dark Matter (DM), where DM appears as strings with tensions different to ours .

Created on 15-05-2025 by Palti, Eran (palti)
Updaded on 15-05-2025 by Palti, Eran (palti)