2000 character limit reached
Blue running of the primordial tensor spectrum (1403.5163v2)
Published 20 Mar 2014 in astro-ph.CO, gr-qc, hep-ph, and hep-th
Abstract: We examine the possibility of positive spectral index of the power spectrum of the primordial tensor perturbation produced during inflation in the light of the detection of the B-mode polarization by the BICEP2 collaboration. We find a blue tilt is in general possible when the slow-roll parameter decays rapidly. We present two known examples in which a positive spectral index for the tensor power spectrum can be obtained. We also briefly discuss other consistency tests for further studies on inflationary dynamics.