Note about leptogenesis from gravity waves in models of inflation

We show how the mechanism recently proposed by Alexander, Peskin, and Sheikh-Jabbari, in which the observed cosmic matter-antimatter asymmetry comes from the contribution of the cosmological tensor perturbations to the gravitational anomaly in the Standard Model, does not work. This holds when taking into account the commutation relations for the creation-annihilation operators associated to the gravitational waves and the geometrical properties of the polarization tensors.