Attractor Solutions in Lorentz Violating Scalar-Vector-Tensor Theory

TL;DR

This paper analyzes the stability and attractor solutions of scalar fields in a Lorentz violating scalar-vector-tensor gravity theory, identifying conditions for inflationary and scaling solutions and deriving parameter constraints.

Contribution

It introduces a specific model with quadratic effective coupling and inverse power-law potential, revealing new stable attractors and their parameter regions.

Findings

Two stable attractors in inflationary scenarios.

Absence of fluid-dominated solutions with barotropic fluid.

Constraints on coupling parameters from nucleosynthesis.

Abstract

We investigate properties of attractors for scalar field in the Lorentz violating scalar-vector-tensor theory of gravity. In this framework, both the effective coupling and potential functions determine the stabilities of the fixed points. In the model, we consider the constants of slope of the effective coupling and potential functions which lead to the quadratic effective coupling vector with the (inverse) power-law potential. For the case of purely scalar field, there are only two stable attractor solutions in the inflationary scenario. In the presence of a barotropic fluid, the fluid dominated solution is absent. We find two scaling solutions: the kinetic scaling solution and the scalar field scaling solutions. We show the stable attractors in regions of ($\gamma$, $\xi$) parameter space and in phase plane plot for different qualitative evolutions. From the standard nucleosynthesis, we derive the constraints for the value of the coupling parameter.