Concept

Forme de l'Univers

Publications associées (146)

The art of simulating the early universe. Part I. Integration techniques and canonical cases

Daniel Garcia Figueroa, Adrien Florio, Wessel Valkenburg, Francisco Torrenti

We present a comprehensive discussion on lattice techniques for the simulation of scalar and gauge field dynamics in an expanding universe. After reviewing the continuum formulation of scalar and gauge field interactions in Minkowski and FLRW backgrounds, ...

2021

Self-interacting neutrinos: Solution to Hubble tension versus experimental constraints

Emmanuel Stamou

Exotic self-interactions among the Standard Model neutrinos have been proposed as a potential reason behind the tension in the expansion rate, H-0, of the universe inferred from different observations. We constrain this proposal using electroweak precision ...

AMER PHYSICAL SOC2021

Euclid : Effects of sample covariance on the number counts of galaxy clusters

Georges Meylan, Yi Wang, Richard Massey

Aims. We investigate the contribution of shot-noise and sample variance to uncertainties in the cosmological parameter constraints inferred from cluster number counts, in the context of the Euclid survey. Methods. By analysing 1000 Euclid-like light cones, ...

EDP SCIENCES S A2021

Relic Gravitational Waves from the Chiral Magnetic Effect

Relic gravitational waves (GWs) can be produced by primordial magnetic fields. However, not much is known about the resulting GW amplitudes and their dependence on the details of the generation mechanism. Here we treat magnetic field generation through the ...

IOP PUBLISHING LTD2021

Einstein-Cartan Portal to Dark Matter

Andrey Shkerin, Inar Timiryasov, Sebastian Zell

It is well known since the works of Utiyama and Kibble that the gravitational force can be obtained by gauging the Poincare group, which puts gravity on the same footing as the standard model fields. The resulting theory-Einstein-Cartan gravity-inevitably ...

AMER PHYSICAL SOC2021

Predictors and predictands of linear response in spatially extended systems

Umberto Maria Tomasini

The goal of response theory, in each of its many statistical mechanical formulations, is to predict the perturbed response of a system from the knowledge of the unperturbed state and of the applied perturbation. A new recent angle on the problem focuses on ...

SPRINGER HEIDELBERG2021

Development and evaluation of galaxy shape measurement algorithms for radio interferometric data

Vasileios Angelopoulos

The purpose of this Thesis is to develop, test, and characterize different models attempting to tackle the problem of measurement of galaxy shapes applied in interferometric observations. Shape measurement is a tool for estimating the underlying shear due ...

EPFL2021

Optimal target assignment for massive spectroscopic surveys

Denis Gillet, Jean-Paul Richard Kneib, Matin Macktoobian

Robotics have recently contributed to cosmological spectroscopy to automatically obtain the map of the observable universe using robotic fiber positioners. For this purpose, an assignment algorithm is required to assign each robotic fiber positioner to a t ...

2020

Effective photon mass and (dark) photon conversion in the inhomogeneous Universe

Kyrylo Bondarenko

Photons traveling cosmological distances through the inhomogeneous Universe experience a great variation in their in-medium induced effective mass. Using the EAGLE suite of hydrodynamical simulations, we infer the free electron distribution and thereby the ...

IOP PUBLISHING LTD2020

Quantifying the information impact of future searches for exoplanetary biosignatures

Claudio Grimaldi

One of the major goals for astronomy in the next decades is the remote search for biosignatures (i.e., the spectroscopic evidence of biological activity) in exoplanets. Here we adopt a Bayesian statistical framework to discuss the implications of such futu ...

NATL ACAD SCIENCES2020

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