4 papers
Kinematic Flow for Banana Loops and Unparticles
Tom Westerdijk, Chen Yang
We extend kinematic flow to momentum-integrated loop-level cosmological correlators, focusing on banana loops of conformally coupled scalars in power-law cosmologies and, in de Sit…
Dark Walker in the Early Universe: A Strongly Coupled Sector Model
Chen Yang
We explore the phenomenology of the ``Dark Walker'' -- an theory with eight flavors of massless fundamental fermions in the dark sector. During inflation, its walkin…
Strongly Coupled Sectors in Inflation: Gapless Theories and Unparticles
Guilherme L. Pimentel, Chen Yang
We compute correlation functions of the primordial density perturbations when they couple to a gapless, strongly coupled sector of spectator fields -- ``unparticles" -- during infl…
Bananas are Unparticles: Differential Equations and Cosmological Bootstrap
Tom Westerdijk, Chen Yang
We establish an exact correspondence between tree-level cosmological correlators with unparticle exchange (at integer scaling dimensions) and banana diagrams of conformally coupled…