1212.1871 (Yuan Zhong et al.)

The linearization of thick K-branes    [PDF]

Yuan Zhong, Yu-Xiao Liu

In this paper, thick $K$-branes refer to four-dimensional domain walls generated by a scalar field with non-standard kinetic term. We first give a gauge independent description of the linear perturbations of a wide class of thick $K$-brane models. Then we decompose the original metric perturbation into 4 scalars, 2 transverse vectors and a transverse-traceless (TT) tensor. We show that each type of these perturbation modes evolves independently. As compared to the standard case, equations of both vector and tensor perturbations are not modified. On the contrary, the non-standard kinetic terms usually cause modifications to the mass spectrum and effective potential of the scalar perturbation. In order to reduce the scalar perturbation equations into a Schr\"odinger like equation, a constraint on the matter Lagrangian is needed. This constraint might be useful in modeling $K$-branes.

View original: http://arxiv.org/abs/1212.1871