20 citations · 44 across the 17 of their papers we have counts for
24 papers
The Devil Went Down to de Sitter: Divergent Effective Field Theory Expansions in Cosmology
Daniele Dorigoni, Laura Engelbrecht, Nadine Nussbaumer +1
Effective field theories (EFTs) in de Sitter space, and in accelerating cosmologies more generally, must capture phenomena absent in flat space, most notably long-range correlation…
Quantum Popcorn: the shape of a phase transition bubble
Kfir Blum, Ipak Fadakar, Omri Rosner +1
A quantum tunneling event in field theory is usually depicted as the materialization of a spherical bubble of true vacuum. The bubble appears at rest, and its profile is the time-s…
The Disordered Universe 2025: Analytic Properties of Amplitudes and Correlators
Mattia Capuano, Chandramouli Chowdhury, Chantelle Esper +6
These lectures provide an introduction to modern techniques for studying the analytic properties of loop-level scattering amplitudes and correlation functions in perturbative quant…
Local Measures in Odd de Sitter
Guilherme L. Pimentel, Nicole Righi, Behrang Tafreshi
We show that massless theories in odd-dimensional de Sitter space have very simple measures---the modulus squared of the late-time wavefunctional---at tree level. They are local fu…
de Sitter Gluon Correlators in Momentum Space
Melvyn Nabavi, Guilherme L. Pimentel, Facundo Rost +2
We show a new diagrammatic representation of tree-level wavefunction coefficients for gluons in four-dimensional de Sitter space at any multiplicity. Its ``disc diagrams" make the…
Recursion Relations, Double Copy and Ward Identities
Grégoire Mathys, Guilherme L. Pimentel, Facundo Rost
We consider correlation functions of massless fields in three-dimensional Anti-de Sitter spacetime. Using embedding-space spinors akin to spinor helicity variables, we show that ma…
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 s…
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…
Searching for Unparticles with the Cosmic Microwave Background
Oliver H. E. Philcox, Guilherme L. Pimentel, Chen Yang
Multi-field models of inflation typically assume that interactions between particles can be treated perturbatively. Strongly-coupled models provide an intriguing alternative and ma…
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…
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…
Unraveling the Spectrum of the Open String
Bruno Bucciotti, Felipe Figueroa, Guilherme L. Pimentel
We construct a large portion of the massive spectrum of the open bosonic string using light-cone quantization, providing explicit oscillator realizations for individual single-part…
Geometry of Kinematic Flow
Daniel Baumann, Harry Goodhew, Austin Joyce +3
We uncover a geometric organization of the differential equations for the wavefunction coefficients of conformally coupled scalars in power-law cosmologies. To do this, we introduc…
Black Hole Critical Collapse in Infinite Dimensions: Continuous Self-Similar Solutions
Craig R. Clark, Guilherme L. Pimentel
We investigate the dynamics of black hole critical collapse in the limit of a large number of spacetime dimensions, . In particular, we study the spherical gravitational collaps…
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…
Algebraic Approaches to Cosmological Integrals
Claudia Fevola, Guilherme L. Pimentel, Anna-Laura Sattelberger +1
Cosmological correlators encode statistical properties of the initial conditions of our universe. Mathematically, they can often be written as Mellin integrals of a certain rationa…
A New Twist on Spinning (A)dS Correlators
Daniel Baumann, Grégoire Mathys, Guilherme L. Pimentel +1
Massless spinning correlators in cosmology are extremely complicated. In contrast, the scattering amplitudes of massless particles with spin are very simple. We propose that the re…
A de Sitter S-matrix from amputated cosmological correlators
Scott Melville, Guilherme L. Pimentel
Extending scattering to states with unphysical mass values (particles ``off their mass shell'') has been instrumental in developing modern amplitude technology for Minkowski spacet…
Kinematic Flow and the Emergence of Time
Nima Arkani-Hamed, Daniel Baumann, Aaron Hillman +3
Perhaps the most basic question we can ask about cosmological correlations is how their strength changes as we smoothly vary kinematic parameters. The answer is encoded in differen…
Differential Equations for Cosmological Correlators
Nima Arkani-Hamed, Daniel Baumann, Aaron Hillman +3
Cosmological fluctuations retain a memory of the physics that generated them in their spatial correlations. The strength of correlations varies smoothly as a function of external k…
A de Sitter -matrix for the masses
Scott Melville, Guilherme L. Pimentel
We define an -matrix for massive scalar fields on a fixed de Sitter spacetime, in the expanding patch co-ordinates relevant for early Universe cosmology. It enjoys many of the s…
Snowmass White Paper: The Cosmological Bootstrap
Daniel Baumann, Daniel Green, Austin Joyce +4
This white paper summarizes recent progress in the cosmological bootstrap, an approach to the study of the statistics of primordial fluctuations from consistency with unitarity, lo…