Remarks on brane and antibrane dynamics

bstract We develop the point of view that brane actions should be understood in the context of effective field theory, and that this is the correct way to treat classical as well as loop divergences. We illustrate this idea in a simple model. We then consider the implications for the dynamics of antibranes in flux backgrounds, focusing on the simplest case of a single antibrane. We argue that that effective field theory gives a valid description of the antibrane, and that there is no instability in this approximation. Further, conservation laws exclude possible nonperturbative decays, aside from the well-known NS5-brane instanton.