Kantowski-Sachs Einstein-aether scalar field cosmological models

A class of positive curvature spatially homogeneous but anisotropic cosmological models within an Einstein-aether gravitational framework are investigated. The matter source is assumed to be a scalar field which is coupled to the expansion of the aether field through a generalized exponential potential. The evolution equations are expressed in terms of expansion-normalized variables to produce an autonomous system of ordinary differential equations suitable for a numerical and qualitative analysis. An analysis of the local stability of the equilibrium points indicates that there exists a range of values of the parameters in which there exists an accelerating expansionary future attractor. In general relativity, scalar field models with an exponential potential V = V 0 e −2 k ϕ have a late-time inflationary attractor for k 2 <1/2; however, it is found that the existence of the coupling between the aether and scalar fields allows for arbitrarily large values of the parameter k .