Relic gravitational wave spectrum, the trans-Planckian physics and Hořava–Lifshitz gravity

Abstract

We calculate the spectrum of the relic gravitational wave due to the trans-Planckian effect in which the standard linear dispersion relations may be modified. Of the modified dispersion relations suggested in the literature which has investigated the trans-Planckian effect, we especially use the Corley–Jacobson dispersion relations. The Corley–Jacobson-type modified dispersion relations can be obtained from Hořava–Lifshitz gravity which is non-relativistic and UV complete. Although it is not clear how the transitions from Hořava–Lifshitz gravity in the UV regime to Einstein gravity in the IR limit occur, we assume that the Hořava–Lifshitz gravity regime is followed by the inflationary phase in Einstein gravity.