Searching for Bispectrum of Stochastic Gravitational Waves with Pulsar
  Timing Arrays
  We study how to probe bispectra of stochastic gravitational waves with pulsar
timing arrays. The bispectrum is a key to probe the origin of stochastic
gravitational waves. In particular, the shape of the bispectrum carries
valuable information of inflation models. We show that an appropriate filter
function for three point correlations enables us to extract a specific
configuration of momentum triangles in bispectra. We also calculate the overlap
reduction functions and discuss strategy for detecting the bispectrum with
multiple pulsars.
