Non-SUSY p-branes, bubbles and tubular branes

We consider non-supersymmetric p-brane solutions of type II string theories characterized by three parameters. When the charge parameter vanishes and one of the other two takes a specific value, the corresponding chargeless solutions can be regular and describe "bubbles" in static (unstable) equilibrium when lifted to d=11. In appropriate coordinates, they represent D6-branes with a tubular topology R-1.P x S6-p when reduced to d=10, called the tubular D6-branes, held in static equilibrium by a fixed magnetic flux (fluxbrane). Moreover, a 'rotation parameter' can be introduced to either of the above two eleven-dimensional configurations, giving rise to a generalized configuration labelling by the parameter. As such, it brings out the relations among non-supersymmetric p-branes, bubbles and tubular D6-branes. Given our understanding on tubular D6-branes, we are able to reinforce the interpretation of the chargeless non-supersymmetric p-branes as representing p-brane-anti-p-brane (or non-BPS p-brane) systems, and understand the static nature and various singularities of these systems in a classical supergravity approximation. (C) 2006 Elsevier B.V. All rights reserved.