Looking for non-gaussianity in Pulsar Timing Arrays through the four point correlator
This work computes the complete four-point correlator for stochastic gravitational wave background Fourier coefficients to find non-Gaussian features missed by standard two-point analyses. The result shows a Gaussian component and a connected, non-Gaussian component whose angular structure generalizes the Hellings and Downs correlation to four pulsars, providing a tool to search for specific physical sources.