Cosmic Microwave Background Observables of Small Field Models of
  Inflation
  We construct a class of single small field models of inflation that can
predict, contrary to popular wisdom, an observable gravitational wave signal in
the cosmic microwave background anisotropies. The spectral index, its running,
the tensor to scalar ratio and the number of e-folds can cover all the
parameter space currently allowed by cosmological observations. A unique
feature of models in this class is their ability to predict a negative spectral
index running in accordance with recent cosmic microwave background
observations. We discuss the new class of models from an effective field theory
perspective and show that if the dimensionless trilinear coupling is small, as
required for consistency, then the observed spectral index running implies a
high scale of inflation and hence an observable gravitational wave signal. All
the models share a distinct prediction of higher power at smaller scales,
making them easy targets for detection.
