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Concept

Perturbation (astronomie)

Publications associées (26)

Advancing spacecraft demisability through a novel composite bolt joint system: a step toward sustainable and safe space environments

Véronique Michaud, Muriel Richard, Alexandre Achille Looten

From the recent awareness of the booming number of space debris and their derived worldwide re-entry event threat originating from the use of high survivability components, complementary mitigation measures must be taken for future orbital elements. In thi ...

2023

Swirling against the forcing: Evidence of stable counterdirected sloshing waves in orbital-shaken reservoirs

François Gallaire, Alessandro Bongarzone, Alice Evelyne Julienne Marcotte

We investigate the response of the free liquid surface in a partially filled circular cylindrical container undergoing a planar elliptic and time-periodic orbit while maintaining fixed its orientation. For small forcing amplitudes and deep liquid layers, w ...

Amer Physical Soc2023

HD 213258: A new rapidly oscillating, super slowly rotating, strongly magnetic Ap star in a spectroscopic binary

Pierre North

We report on HD 213258, an Ap star that we recently identified as presenting a unique combination of rare, remarkable properties. Our study of this star is based on ESPaDOnS Stokes I and V data obtained at seven epochs spanning a time interval slightly sho ...

EDP SCIENCES S A2023

Numerical and experimental investigation of spiral-grooved gas journal bearings

Elia Iseli

Small-scale turbomachinery is increasingly used in carbon-free energy conversion systems, such as commercial or domestic scale heat pumps, fuels cells for transportation and waste heat recovery. The usage of aerodynamic bearings allows the design of compac ...

EPFL2022

Experimental and numerical investigation of the unbalance behavior of rigid rotors supported by spiral-grooved gas journal bearings

Jürg Alexander Schiffmann, Elia Iseli

The forced response of rigid rotors, supported by herringbone-grooved gas journal bearings are investigated numerically and experimentally. The rotor configurations are varied by using end cylinders, attached at both sides of the shaft. Three rotors with d ...

ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD2022

Weakly-supervised Action Transition Learning for Stochastic Human Motion Prediction

Mathieu Salzmann

We introduce the task of action-driven stochastic human motion prediction, which aims to predict multiple plausible future motions given a sequence of action labels and a short motion history. This differs from existing works, which predict motions that ei ...

IEEE COMPUTER SOC2022

Periodic orbits exhibit oblique stripe patterns in plane Couette flow

Tobias Schneider, Florian Reetz

Spatiotemporally chaotic dynamics of transitional plane Couette flow may give rise to regular turbulent-laminar stripe patterns with a large-scale pattern wavelength and an oblique orientation relative to the laminar flow direction. A recent dynamical syst ...

AMER PHYSICAL SOC2021

Topological optomechanically induced transparency

Romain Christophe Rémy Fleury, Farzad Zangeneh Nejad

The interaction of optical and mechanical degrees of freedom can lead to several interesting effects. A prominent example is the phenomenon of optomechanically induced transparency (OMIT), in which mechanical movements induce a narrow transparency window i ...

2020

Local Vulnerabilities and Global Robustness of Coupled Dynamical Systems on Complex Networks

Melvyn Sandy Tyloo

Coupled dynamical systems are omnipresent in everyday life. In general, interactions between individual elements composing the system are captured by complex networks. The latter greatly impact the way coupled systems are functioning and evolving in time. ...

EPFL2020

Nonlinear evolution of the centrifugal instability using a semilinear model

François Gallaire, Eunok Yim

We study the nonlinear evolution of the axisymmetric centrifugal instability developing on a columnar anticyclone with a Gaussian angular velocity using a semilinear approach. The model consists of two coupled equations: one for the linear evolution of the ...

Cambridge University Press2020

Low-dimensional dynamics of two coupled biological oscillators

Felix Naef, Eric Paquet, Colas Noé Droin

The circadian clock and the cell cycle are two biological oscillatory processes that coexist within individual cells. These two oscillators were found to interact, which can lead to their synchronization. Here, we develop a method to identify a low-dimensi ...

NATURE PUBLISHING GROUP2019

Koopmans-Compliant Functionals and Potentials and Their Application to the GW100 Test Set

Nicola Marzari, Nicola Colonna, Ngoc Linh Nguyen

Koopmans-compliant (KC) functionals have been shown to provide accurate spectral properties through a generalized condition of piecewise linearity of the total energy as a function of the fractional addition/removal of an electron to/from any orbital. We a ...

AMER CHEMICAL SOC2019

Coupled-mode theory for stationary and nonstationary resonant sound propagation

Romain Christophe Rémy Fleury, Theodoros Koutserimpas

In this paper, we present a complete analytical derivation of the equations used for stationary and nonstationary wave systems regarding resonant sound transmission and reflection described by the phenomenological coupled-mode theory. We calculate the prop ...

2019

Topological Analog Signal Processing

Romain Christophe Rémy Fleury, Farzad Zangeneh Nejad

Analog signal processors have attracted a tremendous amount of attention recently, as they potentially offer much faster operation and lower power consumption than their digital versions. Yet, they are not preferable for large scale applications due to the ...

Nature Research2019

Many-body perturbation theory calculations using the yambo code

Antimo Marrazzo, Gianluca Prandini

yambo is an open source project aimed at studying excited state properties of condensed matter systems from first principles using many-body methods. As input, yambo requires ground state electronic structure data as computed by density functional theory c ...

2019

Advantageous nearsightedness of many-body perturbation theory contrasted with Kohn-Sham density functional theory

Christoph Leopold Talirz

For properties of interacting electron systems, Kohn-Sham (KS) theory is often favored over many-body perturbation theory (MBPT), owing to its low computational cost. However, the exact KS potential can be challenging to approximate, for example in the pre ...

AMER PHYSICAL SOC2019

Koopmans Meets Bethe-Salpeter: Excitonic Optical Spectra without GW

Nicola Marzari, Nicola Colonna, Paolo Umari

The Bethe Salpeter equation (BSE) can be applied to compute from first-principles optical spectra that include the effects of screened electron hole interactions. As input, BSE calculations require single-particle states, quasiparticle energy levels, and t ...

AMER CHEMICAL SOC2019

Characteristic modes of vibration of Q-balls

Andrey Shkerin

In this report, based on [1], we study analytically small perturbations of classically stable Q-balls in 3+1 dimensions. Models with flat and polynomial potentials are considered. We find that large Q-balls in the model with the flat potential possess soft ...

EDP SCIENCES2018

An adaptive GNSS-based reduced dynamic approach for real time autonomous navigation from the Earth to the Moon

Pierre-André Farine, Cyril Botteron, Vincenzo Capuano, Paul David Blunt, Endrit Shehaj

In this research study we describe our last effort in further improving the achievable Global Navigation Satellite System (GNSS) based navigation performance in an Earth-Moon Transfer Orbit (MTO). The GNSS-based orbital filter we implemented previously wit ...

2017

Rayleigh-Taylor instability under curved substrates: An optimal transient growth analysis

François Gallaire, Pierre-Thomas Paul Brun, Gioele Mariano Nicolò Balestra

We investigate the stability of thin viscous films coated on the inside of a horizontal cylindrical substrate. In such a case, gravity acts both as a stabilizing force through the progressive drainage of the film and as a destabilizing force prone to form ...

Amer Physical Soc2016