Chamblin, A.Emparan García de Salazar, Roberto A.2010-05-062010-05-0619970556-2821https://hdl.handle.net/2445/12360region to the other. We also present a C-type solution that describes neutral bubbles in uniform acceleration, and we use it to construct an instanton that mediates the breaking of a cosmic string by forming bubbles at its ends. The rate for this process is also calculated. Finally, we argue that a similar solution can be constructed for magnetic bubbles, and that it can be used to describe a semiclassical instability of the two-timing vacuum against production of massless monopole pairs.12 p.application/pdfeng(c) The American Physical Society, 1997GravitacióGravitationinfo:eu-repo/semantics/article510690info:eu-repo/semantics/openAccess