Broken Ward Identities Research Articles

Holographic Projection of Electromagnetic Maxwell Theory

The 4D Maxwell theory with single-sided planar boundary is considered. As a consequence of the presence of the boundary, two broken Ward identities are recovered, which, on-shell, give rise to two conserved currents living on the edge. A Kaç-Moody algebra formed by a subset of the bulk fields is obtained with central charge proportional to the inverse of the Maxwell coupling constant, and the degrees of freedom of the boundary theory are identified as two vector fields, also suggesting that the 3D theory should be a gauge theory. Finally the holographic contact between bulk and boundary theory is reached in two inequivalent ways, both leading to a unique 3D action describing a new gauge theory of two coupled vector fields with a topological Chern-Simons term with massive coefficient. In order to check that the 3D projection of 4D Maxwell theory is well defined, we computed the energy-momentum tensor and the propagators. The role of discrete symmetries is briefly discussed.

Impressions on the algebraic renormalization of theN=2supersymmetric Yang-Mills field theories

We investigate the ultraviolet behavior of a class of N=2 supersymmetric Yang-Mills field theories which are built up in terms of N=1 superfields. Our results are obtained within the framework of the so-called algebraic renormalization technique of Becchi, Rouet, and Stora. Thanks to the algebraic renormalization setup, we have been able to write down the most general local counterterm functional which is compatible with all the classical symmetries of the model in the N=1 superspace. As a consequence of having parametrized both physical and unphysical renormalizations of the theory, we have also been able to present its corresponding Callan-Symanzik equation. In particular, due to the existence of a pair of linearly broken Ward identities, the nonrenormalization property of the gauge ghosts' wave functions is also proven to occur in this broad class of N=2 supersymmetric gauge field models.