129 citations · 854 across the 31 of their papers we have counts for
32 papers
Effective Field Theory of Large Scale Structure and Newtonian Motion Gauges
Christian Fidler, Julien Lesgourgues, Antonia Mattes +2
The simplest flavor of the Effective Field Theory of Large Scale Structure is based on Newtonian equations and describes the nonlinear matter density and velocity using Einstein-de…
GW_CLASS: Cosmological Gravitational Wave Background in the Cosmic Linear Anisotropy Solving System
Florian Schulze, Lorenzo Valbusa Dall'Armi, Julien Lesgourgues +5
The anisotropies of the Cosmological Gravitational Wave Background (CGWB) retain information about the primordial mechanisms that source the gravitational waves and about the geome…
Fast and robust Bayesian Inference using Gaussian Processes with GPry
Jonas El Gammal, Nils Schöneberg, Jesús Torrado +1
We present the GPry algorithm for fast Bayesian inference of general (non-Gaussian) posteriors with a moderate number of parameters. GPry does not need any pre-training, special ha…
Euclid: Modelling massive neutrinos in cosmology -- a code comparison
J. Adamek, R. E. Angulo, C. Arnold +133
The measurement of the absolute neutrino mass scale from cosmological large-scale clustering data is one of the key science goals of the Euclid mission. Such a measurement relies o…
CosmicNet II: Emulating extended cosmologies with efficient and accurate neural networks
Sven Günther, Julien Lesgourgues, Georgios Samaras +4
In modern analysis pipelines, Einstein-Boltzmann Solvers (EBSs) are an invaluable tool for obtaining CMB and matter power spectra. To accelerate the computation of these observable…
A Minimal Model for Massive Neutrinos in Newtonian N-body Simulations
Pol Heuschling, Christian Partmann, Christian Fidler
We present a novel method for including the impact of massive neutrinos in cold dark matter N-body simulations. Our approach is compatible with widely employed Newtonian N-body cod…
Fast simulations of cosmic large-scale structure with massive neutrinos
Christian Partmann, Christian Fidler, Cornelius Rampf +1
Accurate cosmological simulations that include the effect of non-linear matter clustering as well as of massive neutrinos are essential for measuring the neutrino mass scale from u…
CosmicNet I: Physics-driven implementation of neural networks within Boltzmann-Einstein solvers
Jasper Albers, Christian Fidler, Julien Lesgourgues +2
Einstein-Boltzmann Solvers (EBSs) are run on a massive scale by the cosmology community when fitting cosmological models to data. We present a new concept for speeding up such code…
Lensing anomalies from the epoch of reionisation
Christian Fidler, Julien Lesgourgues, Christophe Ringeval
Reionisation blurring is a non-linear correction to the cosmic microwave background that acts similar to weak gravitational lensing and that can be computed from linear perturbatio…
The large-scale general-relativistic correction for Newtonian mocks
Julian Adamek, Christian Fidler
We clarify the subtle issue of finding the correct mapping of Newtonian simulations to light-cone observables at very large distance scales. A faithful general-relativistic interpr…
Relativistic bias in neutrino cosmologies
Christian Fidler, Nils Sujata, Maria Archidiacono
Halos and galaxies are tracers of the underlying dark matter structures. While their bias is well understood in the case of a simple Universe composed dominantly of dark matter, th…
Suitable Initial Conditions for Newtonian Simulations with Massive Neutrinos
Christian Fidler, Alexander Kleinjohann
Initial conditions for cosmological N-body simulations are usually calculated by rescaling the present day linear power spectrum obtained from an Einstein-Boltzmann solver to the i…
A Relativistic Interpretation of Bias in Newtonian Simulations
Christian Fidler, Nils Sujata, Cornelius Rampf
Observables of cosmic structures are usually not the underlying matter field but biased tracers of matter, such as galaxies or halos. We show how the bias found in Newtonian N-body…
A new approach to cosmological structure formation with massive neutrinos
Christian Fidler, Alexander Kleinjohann, Thomas Tram +2
We show how Newtonian cosmological simulations can be employed to investigate the non-linear evolution of two particle species in a relativistic context. We discuss the application…
CMB anisotropies from patchy reionisation and diffuse Sunyaev-Zel'dovich effects
Christian Fidler, Christophe Ringeval
Anisotropies in the Cosmic Microwave Background (CMB) can be induced during the later stages of cosmic evolution, and in particular during and after the Epoch of Reionisation. Inho…
General relativistic weak-field limit and Newtonian N-body simulations
Christian Fidler, Thomas Tram, Cornelius Rampf +3
We show how standard Newtonian N-body simulations can be interpreted in terms of the weak-field limit of general relativity by employing the recently developed Newtonian motion gau…
The effect of early radiation in N-body simulations of cosmic structure formation
Julian Adamek, Jacob Brandbyge, Christian Fidler +3
Newtonian N-body simulations have been employed successfully over the past decades for the simulation of the cosmological large-scale structure. Such simulations usually ignore rad…
Relativistic initial conditions for N-body simulations
Christian Fidler, Thomas Tram, Cornelius Rampf +3
Initial conditions for (Newtonian) cosmological N-body simulations are usually set by re-scaling the present-day power spectrum obtained from linear (relativistic) Boltzmann codes…
Kinetic theory of fermions in curved spacetime
Christian Fidler, Cyril Pitrou
We build a statistical description of fermions, taking into account the spin degree of freedom in addition to the momentum of particles, and we detail its use in the context of the…
Cosmological -body simulations including radiation perturbations
Jacob Brandbyge, Cornelius Rampf, Thomas Tram +3
Cosmological -body simulations are the standard tool to study the emergence of the observed large-scale structure of the Universe. Such simulations usually solve for the gravita…
A precise numerical estimation of the magnetic field generated around recombination
Christian Fidler, Guido Pettinari, Cyril Pitrou
We investigate the generation of magnetic fields from non-linear effects around recombination. As tight-coupling is gradually lost when approaching , the velocity dif…
General relativistic corrections to -body simulations and the Zel'dovich approximation
Christian Fidler, Cornelius Rampf, Thomas Tram +3
The initial conditions for Newtonian -body simulations are usually generated by applying the Zel'dovich approximation to the initial displacements of the particles using an init…
Impact of polarisation on the intrinsic CMB bispectrum
Guido W. Pettinari, Christian Fidler, Robert Crittenden +3
We compute the bispectrum induced in the cosmic microwave background (CMB) temperature and polarisation by the evolution of the primordial density perturbations using the second-or…
The intrinsic bispectrum of the Cosmic Microwave Background [PhD thesis]
Guido Walter Pettinari
The CMB bispectrum is a potential window on exciting new physics, as it is sensitive to the non-Gaussian features in the primordial fluctuations, the same fluctuations that evolved…