Publications associées à Approximation des champs faibles

Euclid preparation: XI. Mean redshift determination from galaxy redshift probabilities for cosmic shear tomography

Gianluca Castignani, Yi Wang, Richard Massey, Fabio Finelli

The analysis of weak gravitational lensing in wide-field imaging surveys is considered to be a major cosmological probe of dark energy. Our capacity to constrain the dark energy equation of state relies on an accurate knowledge of the galaxy mean redshift ...

2021

Linearized supergravity with a dynamical preferred frame

Sergey Sibiryakov

We study supersymmetric extension of the Einstein-aether gravitational model where local Lorentz invariance is broken down to the subgroup of spatial rotations by a vacuum expectation value of a timelike vector field called aether. Embedding aether into a ...

Springer Nature2021

Gyrokinetic full-f particle-in-cell simulations on open field lines with PICLS

Emmanuel Lanti, Alberto Bottino, Noé Thomas Elie Ohana

While in recent years gyrokinetic simulations have become the workhorse for theoretical turbulence and transport studies in the plasma core, their application to the edge and scrape-off layer (SOL) region presents significant challenges. In particular, ste ...

2019

Dark Energy Survey year 1 results: Constraints on extended cosmological models from galaxy clustering and weak lensing

Eduardo Sanchez, Jonathan Andrew Blazek, Yi Zhang

We present constraints on extensions of the minimal cosmological models dominated by dark matter and dark energy, Lambda CDM and wCDM, by using a combined analysis of galaxy clustering and weak gravitational lensing from the first-year data of the Dark Ene ...

American Physical Society2019

What do gravitons say about (unimodular) gravity?

Mario Herrero Valea

We revisit the problem of constraining the weak field limit of the gravitational lagrangian from S-matrix properties. From unitarity and Lorentz invariance of the S-matrix of massless gravitons, we derive on-shell gauge invariance to consist on the transve ...

Springer Nature2018

The particle spectrum of parity-violating Poincare gravitational theory

Georgios Karananas

In this paper we investigate the physical spectrum of the gravitational theory based on the Poincare group with terms that are at most quadratic in tetrad and spin connection, allowing for the presence of parity-even as well as parity-odd invariants. We de ...

Iop Publishing Ltd2015

Nonlinear Plasmonic Nanorulers

Olivier Martin, Jérémy Butet

The evaluation of distances as small as few nanometers using optical waves Is a very challenging task that can pave the way for the development of new applications in biotechnology and nanotechnology. In this article, we propose a new measurement method ba ...

Amer Chemical Soc2014

Weak Gravitational Lensing by Large-Scale Structures : A Tool for Constraining Cosmology

Marc Gentile

There is now very strong evidence that our Universe is undergoing an accelerated expansion period as if it were under the influence of a gravitationally repulsive “dark energy” component. Furthermore, most of the mass of the Universe seems to be in the for ...

EPFL2013

On the effect of image denoising on galaxy shape measurements

Frédéric Courbin, Georges Meylan, Marc Gentile, Guldariya Nurbaeva

Weak gravitational lensing is a very sensitive way of measuring cosmological parameters, including dark energy, and of testing current theories of gravitation. In practice, this requires exquisite measurement of the shapes of billions of galaxies over larg ...

2011

Gravitating field-theoretical branes and their excitations

Katarzyna Zuleta Estrugo

This thesis is devoted to studying field-theoretical branes in warped geometries, with emphasis on brane excitations and properties of background solutions. Firstly, we examine the features of a model in which our universe is represented by a local string- ...

EPFL2005