125 citations · 1.1k across the 32 of their papers we have counts for
32 papers
To USR or not to USR: An effective description of two-field dynamics
Samuel Sánchez López, Eemeli Tomberg
Single-field models of inflection point inflation experience a phase of ultra-slow roll (USR), leading to amplified curvature perturbations. Recently, Lorenzoni et al. modified the…
Compaction function in stochastic inflation: a \texttt{FOREST} of type I and II primordial black holes
Chiara Animali, Pierre Auclair, Baptiste Blachier +2
We show how to compute the compaction function within stochastic inflation, by solving the random field dynamics on stochastic binary trees. In this framework, the compaction funct…
Evading the BBN bound with a soft stiff period
Lucy Brissenden, Konstantinos Dimopoulos, Eemeli Tomberg
Cosmic inflation is the leading theory to explain early Universe history and structure formation. Non-oscillatory inflation is a class of models which can naturally introduce a pos…
Effect of stochastic kicks on primordial black hole abundance and mass via the compaction function
Sami Raatikainen, Syksy Rasanen, Eemeli Tomberg
We study stochastic effects in viable ultra-slow-roll inflation models that produce primordial black holes. We consider asteroid, solar, and supermassive black hole seed masses. In…
Eternal inflation near inflection points: a challenge to primordial black hole models
Eemeli Tomberg, Konstantinos Dimopoulos
Inflation with an inflection point potential is a popular model for producing primordial black holes. The potential near the inflection point is approximately flat, with a local ma…
How deep is the dip and how tall are the wiggles in inflationary power spectra?
Vadim Briaud, Alexandros Karam, Niko Koivunen +3
We study linear scalar perturbations in single-field models of inflation featuring a non-attractor phase. These models lead to a peak in the curvature power spectrum that may resul…
Itô, Stratonovich, and zoom-in schemes in stochastic inflation
Eemeli Tomberg
The Itô and Stratonovich approaches are two ways to integrate stochastic differential equations. Detailed knowledge of the origin of the stochastic noise is needed to determine whi…
Stochastic Axion-like Curvaton: Non-Gaussianity and Primordial Black Holes Without Large Power Spectrum
Chao Chen, Anish Ghoshal, Gianmassimo Tasinato +1
We discuss a mechanism of primordial black hole (PBH) formation that does not require specific features in the inflationary potential, revisiting previous literature. In this mecha…
Primordial black hole numbers: standard formulas and charts
Eemeli Tomberg
This brief note presents standard computations of primordial black hole mass given perturbations of scale , and their late-time abundance given their initial…
Primordial black hole compaction function from stochastic fluctuations in ultra-slow-roll inflation
Sami Raatikainen, Syksy Rasanen, Eemeli Tomberg
We study the formation of primordial black holes (PBH) with ultra-slow-roll inflation when stochastic effects are important. We use the formalism and simplify the stochastic e…
Observable Gravitational Waves from Hyperkination in Palatini Gravity and Beyond
Samuel Sánchez López, Konstantinos Dimopoulos, Alexandros Karam +1
We consider cosmology with an inflaton scalar field with an additional quartic kinetic term. Such a theory can be motivated by Palatini modified gravity. Assuming a runaway…
Stochastic constant-roll inflation and primordial black holes
Eemeli Tomberg
Stochastic inflation resolves primordial perturbations non-linearly, probing their probability distribution deep into its non-Gaussian tail. The strongest perturbations collapse in…
Implications of Palatini gravity for inflation and beyond
Ioannis D. Gialamas, Alexandros Karam, Thomas D. Pappas +1
We present an introduction to cosmic inflation in the framework of Palatini gravity, which provides an intriguing alternative to the conventional metric formulation of gravity. In…
Beyond (and back to) Palatini quadratic gravity and inflation
Christian Dioguardi, Antonio Racioppi, Eemeli Tomberg
We study single-field slow-roll inflation embedded in Palatini gravity where grows faster than . Surprisingly, the consistency of the theory requires the Jordan…
Numerical stochastic inflation constrained by frozen noise
Eemeli Tomberg
Stochastic inflation can resolve strong inflationary perturbations, which seed primordial black holes. I present a fast and accurate way to compute these perturbations in typical b…
Anatomy of single-field inflationary models for primordial black holes
Alexandros Karam, Niko Koivunen, Eemeli Tomberg +2
We construct an analytically solvable simplified model that captures the essential features for primordial black hole (PBH) production in most models of single-field inflation. The…
Palatini Quintessential Inflation
Konstantinos Dimopoulos, Alexandros Karam, Samuel Sánchez López +1
We construct a model of quintessential inflation in Palatini gravity employing a scalar field with a simple exponential potential and coupled to gravity with a running non-mi…
Modelling Quintessential Inflation in Palatini Modified Gravity
Konstantinos Dimopoulos, Alexandros Karam, Samuel Sánchez López +1
We study a model of quintessential inflation constructed in modified gravity with a non-minimally coupled scalar field, in the Palatini formalism. Our non-minimal inflaton fi…
The Linear Regime of Tachyonic Preheating
Niko Koivunen, Eemeli Tomberg, Hardi Veermäe
Tachyonic preheating is realized when the inflaton repeatedly returns to a convex region of the potential during the post-inflationary oscillating phase. This will induce a strong…
Slow-roll inflation in Palatini gravity
Christian Dioguardi, Antonio Racioppi, Eemeli Tomberg
We study single field slow-roll inflation in the presence of gravity in the Palatini formulation. In contrast to metric , when rewritten in terms of an auxiliary field…
Implications of stochastic effects for primordial black hole production in ultra-slow-roll inflation
Daniel G. Figueroa, Sami Raatikainen, Syksy Rasanen +1
We study the impact of stochastic noise on the generation of primordial black hole (PBH) seeds in ultra-slow-roll (USR) inflation with numerical simulations. We consider the non-li…
A numerical approach to stochastic inflation and primordial black holes
Eemeli Tomberg
Certain models of cosmic inflation produce strong cosmological perturbations at short length scales, which may later collapse into primordial black holes. To find the statistics of…
Unit conversions and collected numbers in cosmology
Eemeli Tomberg
This note collects together useful unit conversions and numerical values from early universe cosmology. It is a quick reference that can be used to make easy order-of-magnitude est…
Tachyonic Preheating in Plateau Inflation
Eemeli Tomberg, Hardi Veermäe
Plateau inflation is an experimentally consistent framework in which the scale of inflation can be kept relatively low. Close to the edge of the plateau, scalar perturbations are s…