New Type of Vector Gauge Theory from Noncommutative Geometry

Using the formalism of noncommutative geometric gauge theory based on the superconnection concept, we construct a new type of vector gauge theory possessing a shift-like symmetry and the usual gauge symmetry. The new shift-like symmetry is due to the matrix derivative of the noncommutative geometric gauge theory, and this gives rise to a mass term for the vector field without introducing the Higgs field. This construction becomes possible by using a constant one form even matrix for the matrix derivative, for which only constant zero form odd matrices have been used so far. The fermionic action in this formalism is also constructed and discussed.Comment: 12 pages, LaTeX file, to appear in Phys. Lett.

Geometrical Interpretation of BRST Symmetry in Topological Yang-Mills-Higgs Theory

We study topological Yang-Mills-Higgs theories in two and three dimensions and topological Yang-Mills theory in four dimensions in a unified framework of superconnections. In this framework, we first show that a classical action of topological Yang-Mills type can provide all three classical actions of these theories via appropriate projections. Then we obtain the BRST and anti-BRST transformation rules encompassing these three topological theories from an extended definition of curvature and a geometrical requirement of Bianchi identity. This is an extension of Perry and Teo's work in the topological Yang-Mills case. Finally, comparing this result with our previous treatment in which we used the ``modified horizontality condition", we provide a meaning of Bianchi identity from the BRST symmetry viewpoint and thus interpret the BRST symmetry in a geometrical setting.Comment: 16 pages, LaTeX fil