Goldstone bosons and solitons on the brane

Abstract

In this work we compute the effective action describing the low-energy brane Goldstone-boson dynamics. The Goldstone bosons or branons appear because the brane spontaneously breaks the translational invariance along the extra dimensions. We discuss the Higgs-like mechanism in which the Kaluza-Klein gauge fields absorb the Goldstone bosons and acquire mass. We also present the explicit form of the effective action describing the low-energy interactions between the three-brane Goldstone bosons and the Standard Model fields. In addition to the branons, two new kinds of states arise corresponding to Skyrmion-like solutions and wrapped states. We study the main properties of these states, their geometrical interpretation and the relations between them.