Inflation with a Planck-scale frequency cutoff - art. no. 123502

The implementation of a Planck-scale high frequency and short wavelength cu toff in quantum theories on expanding backgrounds may have potentially nont rivial implications, such as the breaking of local Lorentz invariance and t he existence of a yet unknown mechanism for the creation of vacuum modes. I n scenarios where inflation begins close to the cutoff scale, these effects could have observable consequences as trans-Planckian modes are redshifted to cosmological scales. In close analogy with similar studies of Hawking r adiation, st simple theory of a minimally coupled scalar field in de Sitter space is studied, with a high frequency cutoff imposed by a nonlinear disp ersion relation. Under certain conditions the model predicts deviations fro m the standard inflationary scenario. We also comment on the difficulties i n generalizing fluid models of Hawking radiation to cosmological space-time s.