Novel thick brane solutions with U(1) symmetry breaking

Abstract

In this work, using two scalar fields ($\varphi$, $\psi$) coupled to 4 + 1 dimensional gravity, we construct novel topological brane solutions through an explicit U(1) symmetry breaking term. The potential of this model is constructed so that two distinct degenerate vacua in the $\varphi$ field exist, in analogy to the ${\varphi }^4$ potential. Therefore, brane solutions appear due to the vacuum structure of the $\varphi$ field. However, the topology and vacuum structure in the $\psi$ direction depends on the symmetry breaking parameter ${\beta }^2$, which leads to different types of branes. As a result, one can interpret the present model as a combination of a ${\varphi }^4$ brane with an auxiliary field, which leads to deviations from the ${\varphi }^4$ system with the brane achieving a richer internal structure. Furthermore, we analyse in detail the behaviour of the superpotentials, the warp factors, the Ricci and Kretschmann scalars and the Einstein tensor components. In addition to this, we explore the stability of the brane in terms of the free parameters of the model. The analysis presented here complements previous work and is sufficiently novel to be interesting.