Душан Ђорђевић

13. априла 2022.

У оквиру семинара Групе за гравитацију, честице и поља Института за физику у Београду, у петак, 15. априла 2022. године у 11 часова путем BigBlueButton платформе, Душан Ђорђевић (Физички факултет у Београду), одржаће предавање:

Noncommutative D=5 Chern-Simons Gravity: Kaluza-Klein Reduction and Chiral Gravitational Anomaly


Chern-Simons (CS) theory has greatly influenced physics and physicists during the past half-century. In this seminar, we will review some basic facts about Chern-Simons Lagrangians defined on some (2n-1)-dimensional manifold. We will then show how CS theory can be connected with gravity. Our focus will be on an SO(4,2) CS gravity in five dimensions and its connections with four-dimensional gravitation. Furthermore, we will analyse the noncommutative deformation of SO(4,2) CS gravity using the geometric Siberg-Witten map. This theory has a nontrivial first-order correction in \theta. By performing Kalutza-Klein dimensional reduction and suitable symmetry breaking, we obtain an effective, four-dimensional gravity theory that has Einstein-Hilbert action with (negative) cosmological constant as its classical (commutative) limit. We then proceed to analyse some concrete solutions of the field equations. We show that AdS space-time remains a solution after including the first-order corrections. On the other hand, AdS-Schwarzschild black hole solution develops a torsion that we explicitly compute. Moreover, we will see that this modified solution implies the existence of a chiral gravitational anomaly if one couples massless Dirac fermions to this NC background.

This seminar is based on arXiv:2203.05020

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