Nordita seminar

Gravity as constrained BF theory

by Remigiusz Durka (Wroclaw University)



In the late 70's MacDowell and Mansouri introduced a new approach to gravity based on broken symmetry of the gauge theory. Recent interest in his formalism has been renewed in the form of constrained topological BF theory. The equations of motion of this theory turn out to be the vacuum Einstein equations. By solving the B field equations one finds that the action of this theory contains not only the standard Einstein-Hilbert action with cosmological constant term, but also the Holst term proportional to the inverse of the Immirzi parameter, as well as a combination of topological invariants (Euler, Pontryagin, and Nieh-Yan). This model easily provides supersymmetric extension of the theory and offers other interesting features.