Extended matter coupled to BF theory

Abstract

Recently, a topological field theory of membrane matter coupled to BF theory in arbitrary spacetime dimensions was proposed [J. C. Baez and A. Perez, Adv. Theor. Math. Phys. 11, 3 (2007).]. In this paper, we discuss various aspects of the four-dimensional theory. First, we study classical solutions leading to an interpretation of the theory in terms of strings propagating on a flat spacetime. We also show that the general classical solutions of the theory are in one-to-one correspondence with solutions of Einstein's equations in the presence of distributional matter (cosmic strings). Second, we quantize the theory and present, in particular, a prescription to regularize the physical inner product of the canonical theory. We show how the resulting transition amplitudes are dual to evaluations of Feynman diagrams coupled to three-dimensional quantum gravity. Finally, we remove the regulator by proving the topological invariance of the transition amplitudes.