Lorentz violating inflation

We explore the impact of Lorentz violation on the inflationary scenario. More precisely, we study the inflationary scenario in the scalar-vector-tensor theory where the Lorentz violating vector is constrained to be unit and timelike. It turns out that the Lorentz violating vector affects the dynamics of the chaotic inflationary model and divides the inflationary stage into two parts: the Lorentz violating stage and the standard slow roll stage. We show that the universe is expanding as a de Sitter space-time in the Lorentz violating stage although the inflaton field is rolling down the potential. More interestingly, we find the exact Lorentz violating inflationary solutions in the absence of the inflaton potential. In this case, the inflation is completely associated with the Lorentz violation.