Dynamical and static solutions to $R=0$-scalar-tensor theory

TL;DR

This paper explores new dynamical and static solutions in scalar-tensor theories with zero Ricci scalar, analyzing their behavior near singularities and identifying heteroclinic orbits connecting these singularities.

Contribution

It introduces novel normal and phantom solutions in scalar-tensor theory, including the characterization of Bianchi I Kasner exponents and the nature of heteroclinic orbits.

Findings

Dynamical solutions are heteroclinic orbits connecting singularities

Purely transverse expansion can occur near singularities

New static and dynamical solutions in scalar-tensor theory

Abstract

We consider the most cosmologically interesting and relevant case of scalar-tensor theory (STT) and derive new normal and phantom, dynamical and static, solutions. We determine the Bianchi I Kasner exponents and show that the dynamical solutions are heteroclinic orbits connecting two singularities. Approaching the singularities, a purely transverse expansion (no radial expansion or collapse) may occur.