On gravitational waves generated during inflation

We study cosmological gravitational waves generated during inflation under the influence of a decaying cosmological ''constant''. A non-perturbative contribution of the dynamical cosmological ''constant'' to the tensor modes is considered. As applications of the model we study the well-known cases Λ(t) = σH² and Λ(t) = θH. The spectrum of gravitational waves results scale invariant only for the first case, leaving this to new proposals of the form: Λ(t) = f(H,H²), in order to include inflation in some Λ(t)CDM models. We also found that the non-perturbative contributions of Λ(t), accelerate the decreasing of the amplitude of gravitational waves during a power-law inflationary stage, by an exponential factor