12 papers
Feynman Tree Theorem and the Gelfand--Yaglom Formula
Ipak Fadakar, Guilherme L. Pimentel, Behrang Tafreshi
The Gelfand--Yaglom formula equates the one-loop determinant of a Schrödinger operator with Dirichlet boundary conditions to the solution of an initial value problem. Following a…
The Cosmological Grassmannian
Mattia Arundine, Daniel Baumann, Mang Hei Gordon Lee +2
We introduce the orthogonal Grassmannian as a novel kinematic space for describing correlators of massless spinning fields in de Sitter space. By automatically encoding the constra…
Amplifying the Cosmological Collider with Ghost Spectators
Matheus Curado Ferreira, F. T. Falciano, Guilherme L. Pimentel
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 fo…
On Cosmological Correlators at One Loop
Guilherme L. Pimentel, Tom Westerdijk
We study equal-time in-in correlators of massless scalar fields in flat space at one loop. Using the time-ordered decomposition of correlators together with a cosmological analogue…
Cosmological Collider in the Grassmannian
Mattia Arundine, Guilherme L. Pimentel
We revisit the computation of four-point wavefunction coefficients and correlators for external conformally coupled scalars exchanging a particle of generic mass and spin. Much of…
Strongly Coupled Sectors in Inflation: Gapped Theories of Unparticles
Yikun Jiang, Guilherme L. Pimentel, Chen Yang
We consider a novel scenario for a strongly coupled spectator sector during inflation, that of a higher dimensional conformal field theory with large anomalous dimensions -- ``unpa…