Amplifying the Cosmological Collider with Ghost Spectators
Abstract
Ghost inflation is a well-known framework in which cosmological fluctuations can generate enhanced primordial non-Gaussianity, typically of the equilateral type. In its original form, however, it is in tension with current observational constraints. Here we instead consider a setup in which a standard inflaton drives the background evolution, while excitations of a ghost condensate act as spectator fields that interact with the inflaton. This proposal fits naturally within the cosmological collider program: the exchanged particle has a modified dispersion relation, . We show that this ghost-inspired dynamics weakens the usual Boltzmann suppression, similarly to models with a very small effective sound speed, yielding an enhanced bispectrum signal relative to standard cosmological collider scenarios. At the same time, the horizon-crossing scale remains a free parameter of the theory. As a result, the model shares features of both the de Sitter bootstrap and boostless frameworks. Finally, we derive the differential equations governing cosmological correlators in the ghost-collider setup. Their structure reflects the quadratic momentum dependence of the dispersion relation and distinguishes this scenario from conventional relativistic cases.
Cite
@article{arxiv.2601.14413,
title = {Amplifying the Cosmological Collider with Ghost Spectators},
author = {Matheus Curado Ferreira and F. T. Falciano and Guilherme L. Pimentel},
journal= {arXiv preprint arXiv:2601.14413},
year = {2026}
}
Comments
27 pages, 8 figures