178 citations · 543 across the 28 of their papers we have counts for
29 papers
Strongly mixed cosmological collider at unequal sound speeds
Javier Huenupi, Gonzalo A. Palma, Spyros Sypsas
We derive the canonically normalized modes of a two-field inflationary system with arbitrary constant quadratic mixing and unequal sound speeds and for the curvature an…
Pushing the Primordial Frontier: Cosmological Collider Signatures at Strong Mixing
Javier Huenupi, Claudio Muñoz, Gonzalo A. Palma +1
We develop an analytic treatment of primordial non-Gaussianity in multifield inflation that is nonperturbative in the constant curvature--isocurvature mixing strength . Using ex…
Pushing the Primordial Frontier: Exact Linear Solutions in Multifield Inflation
Javier Huenupi, Claudio Muñoz, Gonzalo A. Palma +1
We present exact analytic solutions for the linear dynamics of a two-field inflationary system in which the primordial curvature perturbation is coupled to an isocurvature pert…
Confronting infrared divergences in de Sitter: loops, logarithms and the stochastic formalism
Gonzalo A. Palma, Spyros Sypsas, Danilo Tapia
A well-established result in quantum field theory in four-dimensional de Sitter space is that the vacuum state of a massless scalar field breaks the de Sitter isometry group, leadi…
A note on loop resummation in de Sitter spacetime with the wavefunction of the universe approach
Javier Huenupi, Ellie Hughes, Gonzalo A. Palma +1
We analyze the computation of -point correlation functions in de Sitter spacetime, including loop corrections, using the wavefunction of the universe approach. This method consi…
Particle creation from non-geodesic trajectories in multifield inflation
Nicolás Parra, Spyros Sypsas, Gonzalo A. Palma +1
Particle production in de Sitter spacetime arises from the exponential expansion of space, rendering the Bunch-Davies vacuum perceived as a particle-containing state by late-time o…
Regularizing infrared divergences in de Sitter spacetime: Loops, dimensional regularization, and cutoffs
Javier Huenupi, Ellie Hughes, Gonzalo A. Palma +1
Correlation functions of light scalar fields in de Sitter spacetime, computed via standard perturbation theory, often exhibit secular growth characterized by time-dependent diverge…
Nonlinear instability and solitons in a self-gravitating fluid
G. N. Koutsokostas, S. Sypsas, O. Evnin +2
We study a spherical, self-gravitating fluid model, which finds applications in cosmic structure formation. We argue that since the system features nonlinearity and gravity-induced…
Revisiting stochastic inflation with perturbation theory
Gonzalo A. Palma, Spyros Sypsas
A long-standing problem in primordial cosmology is to understand the precise relation between the stochastic formalism and standard perturbation theory for light scalar fields in i…
Non-Gaussian statistics of de Sitter spectators: A perturbative derivation of stochastic dynamics
Gonzalo A. Palma, Spyros Sypsas
Scalar fields interacting with the primordial curvature perturbation during inflation may communicate their statistics to the latter. This situation motivates the study of how the…
De Sitter bubbles from anti-de Sitter fluctuations
Anxo Biasi, Oleg Evnin, Spyros Sypsas
Cosmological acceleration is difficult to accommodate in theories of fundamental interactions involving supergravity and superstrings. An alternative is that the acceleration is no…
Primordial gravitational waves from excited states
Jacopo Fumagalli, Gonzalo A. Palma, Sébastien Renaux-Petel +3
We show that a scalar excited state with large occupation numbers during inflation leads to an enhancement of tensor modes and a characteristic pattern of order-one oscillations in…
Note on initial conditions for small-field inflation
Ignatios Antoniadis, Auttakit Chatrabhuti, Hiroshi Isono +1
We show that initial conditions for small-field inflation can be determined quantum mechanically by introducing a suitable flattened region in the scalar potential. The inflaton is…
Seeding primordial black holes in multifield inflation
Gonzalo A. Palma, Spyros Sypsas, Cristobal Zenteno
The inflationary origin of primordial black holes (PBHs) relies on a large enhancement of the power spectrum of the curvature fluctuation at wavelengths much shorter than…
Evaporating primordial black holes as varying dark energy
Savvas Nesseris, Domenico Sapone, Spyros Sypsas
If light enough primordial black holes (PBH) account for dark matter, then its density decreases with time as they lose mass via Hawking radiation. We show that this time-dependenc…
Non-Gaussian CMB and LSS statistics beyond polyspectra
Gonzalo A. Palma, Bruno Scheihing Hitschfeld, Spyros Sypsas
Cosmic inflation may have led to non-Gaussian initial conditions that cannot be fully parametrised by 3- and/or 4-point functions. In this work, we discuss various strategies to se…
Reconstructing the Inflationary Landscape with Cosmological Data
Xingang Chen, Gonzalo A. Palma, Bruno Scheihing Hitschfeld +1
We show that the shape of the inflationary landscape potential may be constrained by analyzing cosmological data. The quantum fluctuations of fields orthogonal to the inflationary…
Landscape tomography through primordial non-Gaussianity
Xingang Chen, Gonzalo A. Palma, Walter Riquelme +2
In this paper, we show how the structure of the landscape potential of the primordial Universe may be probed through the properties of the primordial density perturbations responsi…
Cross-tests of CMB features in the primordial spectra
Spyros Sypsas
The recent Planck data on the power spectrum of temperature anisotropies of the cosmic microwave background marginally support deviations from the CDM model at several multipole…
Constraints on inflation with LSS surveys: features in the primordial power spectrum
Gonzalo A. Palma, Domenico Sapone, Spyros Sypsas
We analyse the efficiency of future large scale structure surveys to unveil the presence of scale dependent features in the primordial spectrum --resulting from cosmic inflation--…
Shapes and features of the primordial bispectrum
Jinn-Ouk Gong, Gonzalo A. Palma, Spyros Sypsas
If time-dependent disruptions from slow-roll occur during inflation, the correlation functions of the primordial curvature perturbation should have scale-dependent features, a case…
Scale invariance of the primordial tensor power spectrum
Gonzalo A. Palma, Bastian Pradenas, Walter Riquelme +1
Future cosmic microwave background polarization experiments will search for evidence of primordial tensor modes at large angular scales, in the multipole range $4 \leq \ell \leq 50…
Direct search for features in the primordial bispectrum
Stephen Appleby, Jinn-Ouk Gong, Dhiraj Kumar Hazra +2
We study features in the bispectrum of the primordial curvature perturbation correlated with the reconstructed primordial power spectrum from the observed cosmic microwave backgrou…
Higher derivatives and power spectrum in effective single field inflation
Jinn-Ouk Gong, Min-Seok Seo, Spyros Sypsas
We study next-to-leading corrections to the effective action of the curvature perturbation obtained by integrating out the coupled heavy isocurvature perturbation. These correction…