Clustering Fossils in Solid Inflation

TL;DR

The work investigates tensor fossils in solid inflation, where Maldacena's consistency condition is violated and long-wavelength tensor modes can imprint a quadrupole on the scalar power spectrum via the tensor-scalar-scalar bispectrum. By analyzing the full parameter space of F[X,Y,Z] under Planck non-Gaussianity bounds, the authors derive the scalar-scalar-scalar bispectrum with a generalized Q_eff and the tensor-scalar-scalar bispectrum B_{hζζ}, establishing how the squeezed-limit signals depend on independent parameters F_Y/F and F_Z/F. They map these BIS signals to a quadrupole in the late-time scalar power spectrum and evaluate detectability with minimum-variance estimators, finding that, despite Planck constraints, a sizable quadrupole could be accessible to future surveys like EUCLID or 21 cm experiments. Overall, the paper extends prior analyses by enabling independent F_Y and F_Z, clarifying the viable non-Gaussianity regime, and outlining concrete observational prospects for distinguishing solid inflation from standard slow-roll models.

Abstract

In solid inflation the single field non-Gaussianity consistency condition is violated. As a result, the long tensor perturbation induces observable clustering fossils in the form of quardupole anisotropy in large scale structure power spectrum. In this work we revisit the bispectrum analysis for the scalar-scalar-scalar and tensor-scalar-scalar for the general parameter space of solid. We consider the parameter space of the model in which the level of non-Gaussianity generated is consistent with Planck constraints. Specializing to this allowed range of model parameter, we calculate the quadrupole anisotropy induced from the long tensor perturbations on the power spectrum of scalar perturbations. We argue that imprints of clustering fossil from primordial gravitational waves on large scale structures can be detected from the future galaxy surveys.