Cosmic String in Scalar-Tensor Gravity

Abstract

The gravitational properties of a local cosmic string in the framework of scalar-tensor gravity are examined. We find the metric in the weak-field approximation and we show that, contrary to the General Relativity case, the cosmic string in scalar-tensor gravitation exerces a force on non-relativistic, neutral test particle. This force is proportional to the derivative of the conformal factor $A^{2}(ϕ)$ and it is always attractive. Moreover, this force could have played an important role at the Early Universe, although nowadays it can be neglegible. It is also shown that the angular separation $δφ$ remains unaltered for scalar-tensor cosmic strings.