136 citations · 359 across the 17 of their papers we have counts for
17 papers · 1 filter
Power Spectrum Emulators from Neural Networks and Tree-Based Methods
Andrei Lazanu
We use two subsets of 2000 and 1000 Quijote simulations to build two power spectrum emulators, allowing for fast computations of the non-linear matter power spectrum. The first emu…
Primordial gravitational waves in DHOST inflation
Philippe Brax, Andrei Lazanu
We consider DHOST inflationary models with a shift symmetry leading to a de Sitter space-time at the background cosmological level. Deviations from scale invariance of the scalar a…
A DHOST model of inflation: CMB constraints from the power spectrum and the bispectrum
Andrei Lazanu
We build an inflationary model based on Degenerate Higher Order Scalar Tensor (DHOST) theories in a de Sitter background. We determine the scale-dependent power spectrum of curvatu…
CMB bispectrum constraints on DHOST inflation
Wuhyun Sohn, Andrei Lazanu, Philippe Brax +1
We present the first direct constraints on a Degenerate Higher Order Scalar Tensor (DHOST) inflation model using the Planck 2018 Cosmic Microwave Background (CMB) results on non-Ga…
Non-Gaussianity in DHOST inflation
Philippe Brax, Andrei Lazanu
DHOST inflation models where deviations from a pure de Sitter background are induced by an axion-like potential can lead to large non-Gaussianities. We investigate the nature of no…
The reach of next-to-leading-order perturbation theory for the matter bispectrum
Davit Alkhanishvili, Cristiano Porciani, Emiliano Sefusatti +4
We provide a comparison between the matter bispectrum derived with different flavours of perturbation theory at next-to-leading order and measurements from an unprecedentedly large…
Scale-dependence in DHOST inflation
Philippe Brax, Andrei Lazanu
We study the inflationary consequences of Degenerate Higher Order Scalar Tensor (DHOST) theories in a de Sitter background. We perturb the de Sitter background by operators breakin…
Extracting cosmological parameters from N-body simulations using machine learning techniques
Andrei Lazanu
We make use of snapshots taken from the Quijote suite of simulations, consisting of 2000 simulations where five cosmological parameters have been varied (, , , a…
K-mouflage Imprints on Cosmological Observables and Data Constraints
Giampaolo Benevento, Marco Raveri, Andrei Lazanu +4
We investigate cosmological constraints on K-mouflage models of modified gravity. We consider two scenarios: one where the background evolution is free to deviate from CDM (K-mo…
Modelling the matter bispectrum towards nonlinear scales - two and three loops in perturbation theories
Andrei Lazanu
I compute the matter bispectrum of large-scale structure up to two loops in the Standard Perturbation Theory and up to three loops in the MPTbreeze renormalised perturbation theory…
The two and three-loop matter bispectrum in perturbation theories
Andrei Lazanu, Michele Liguori
We evaluate for the first time the dark matter bispectrum of large-scale structure at two loops in the Standard Perturbation Theory and at three loops in the Renormalised Perturbat…
Constraining Primordial non-Gaussianity with Bispectrum and Power Spectum from Upcoming Optical and Radio Surveys
Dionysios Karagiannis, Andrei Lazanu, Michele Liguori +3
We forecast constraints on primordial non-Gaussianity (PNG) and bias parameters from measurements of galaxy power spectrum and bispectrum in future radio continuum and optical surv…
Bispectrum Modelling in Large Scale Structure - A Three Shape Model
Andrei Lazanu
We study the matter bispectrum of large structure by comparing theoretical models (perturbation theories and halo models) to numerical simulations using shape and amplitude correla…
Matter bispectrum of large-scale structure with Gaussian and non-Gaussian initial conditions: Halo models, perturbation theory, and a three-shape model
Andrei Lazanu, Tommaso Giannantonio, Marcel Schmittfull +1
We study the matter bispectrum of large-scale structure by comparing the predictions of different perturbative and phenomenological models with the full three-dimensional bispectru…
Matter bispectrum of large-scale structure: Three-dimensional comparison between theoretical models and numerical simulations
Andrei Lazanu, Tommaso Giannantonio, Marcel Schmittfull +1
We study the matter bispectrum of the large-scale structure by comparing different perturbative and phenomenological models with measurements from -body simulations obtained wit…
Constraints on the Nambu-Goto cosmic string contribution to the CMB power spectrum in light of new temperature and polarisation data
Andrei Lazanu, E. P. S. Shellard
Cosmic strings generate vector and tensor modes in the B-channel of polarization, as well as the usual temperature power spectrum and E-mode polarization spectrum. We use the power…
CMB power spectrum of Nambu-Goto cosmic strings
Andrei Lazanu, E. P. S. Shellard, Martin Landriau
We improve predictions of the cosmic microwave background (CMB) power spectrum induced by cosmic strings by using source terms obtained from Nambu-Goto network simulations in an ex…