Blue-tilted Primordial Gravitational Waves from Massive Gravity
  We study a theory of massive tensor gravitons which predicts blue-tilted and
largely amplified primordial gravitational waves. After inflation, while their
mass is significant until it diminishes to a small value, gravitons are diluted
as non-relativistic matter and hence their amplitude can be substantially
amplified compared to the massless gravitons which decay as radiation. We show
that such gravitational waves can be detected by interferometer experiments,
even if their signal is not observed on the CMB scales.
