Primordial stochastic gravitational wave background anisotropies: in-in formalization and applications

Abstract Primordial non-Gaussianities of the scalar(tensor)-tensor-tensor type supporting a non-trivial squeezed component are known to induce anisotropies in stochastic gravitational wave background. We derive explicit form such by making use, for first time this context, in-in formalism cosmological correlation functions. After illustrating general method and using it minimal single-field slow-roll case, we apply multi-field models, providing both tree-level one-loop example. First, make contact with previous results on due presence an extra spin-2 field during inflation. Secondly, calculate 1-loop scalar-tensor-tensor three-point function context so-called supersolid The corresponding anisotropy is induced atop signal that may be sufficiently large detection.