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**Time: ** 22. February 2019, 11:00h

**Place: ** Institute of Physics, room 360 (ex-room 300)

**Speaker: ** Raju Roychowdhury

**Title: ** Poisson Lie symmetry and Yang-Baxter sigma model

**Abstract:**

In this talk we will explain how Poisson-Lie T-duality helped us to solve an old problem in the theory of integrable models. We will see how one can deform a sigma model to give rise to what is known as epsilon-deformed principal chiral model or Yang-Baxter sigma model. The deformed model is Poisson-Lie symmetric and still integrable with respect to the same Lax pair as that of the original model and have the same system of equations describing their dynamics. This is due to the fact that the deformed target of the string and the non-deformed target of the string can be expressed by the same first order dynamics.

**Time: ** 20. February 2019, 11:00h

**Place: ** Institute of Physics, room 360 (ex-room 300)

**Speaker: ** Raju Roychowdhury

**Title: ** Emergent gravity and brane correspondence between topological T-duals via generalised complex geometry

**Abstract:**

During past few years, I started developing the formalism of emergent gravity which naturally admits an in-built generalized geometric structure and hence in quite similar to the DFT formalism of Hull and Zwiebach in spirit. We are trying to use the generalized geometric point of view to study topological T-duality that arises in emergent gravity. The approach aims to build a Courant isomorphism between T-duals and thus transport generalized complex structures between them. We are trying to use the machinery developed by Gualtieri and Cavalcanti to transport generalized complex brane between T-duals. We want to study various explicit example of this phenomenon of geometric T-duality and explore its manifestation in Stringy geometry.

**Time: ** 18. February 2019, 12:00h

**Place: ** Institute of Physics, library room "Dragan PopoviÄ‡"

**Speaker: ** Raju Roychowdhury

**Title: ** Emergent spacetime, topology change and resolution of singularity

**Abstract:**

The contemporary physics has revealed growing evidences that the emergence can be applied to not only biology and condensed matter systems but also to gravity and spacetime. We observe that noncommutativity necessarily implies emergent spacetime. In Emergent Gravity approach the spacetime geometry is defined by U(1) gauge fields on noncommutative (NC) spacetime. Accordingly the topology of spacetime is determined by the topology of NC U(1) gauge fields. We show that topology change of spacetime is ample in emergent gravity and the subsequent resolution of singularity is possible in NC spacetime. Thus emergent gravity provides a well-defined mechanism for topology change of spacetime which does not suffer from any singularity in sharp contrast to general relativity.

**Seminars for the year:**
2019
2018
2017
2016
2015
2014
2013
2012
2011
2010
2009
2008
2007