Publications associées à Pp-wave spacetime

Impact of microwave beam scattering by density fluctuations on the electron-cyclotron power deposition profile in tokamaks

Stefano Coda, Joan Decker, Oleg Krutkin, Umesh Kumar, Jean Arthur Cazabonne

Electron-cyclotron waves are a tool commonly used in tokamaks, in particular to drive current. Their ability to drive current in a very localized manner renders them an optimal tool for MHD mode mitigation. However, such applications require high accuracy ...

IOP Publishing Ltd2024

Classical soft graviton theorem rewritten

Biswajit Sahoo

Classical soft graviton theorem gives the gravitational wave-form at future null infinity at late retarded time u for a general classical scattering. The large u expansion has three known universal terms: the constant term, the term proportional to 1/u and ...

Springer Nature2022

A proof of the instability of AdS for the Einstein-massless Vlasov system

Georgios Moschidis

In recent years, the conjecture on the instability of Anti-de Sitter spacetime, put forward by Dafermos-Holzegel (Dynamic instability of solitons in 4 + 1 dimesnional gravity with negative cosmological constant, 2006. https://www.dpmms.cam.ac.uk/similar to ...

SPRINGER HEIDELBERG2022

A simple theoretical model for estimating the frequency characteristics of black hole mergers

Roberto Guarino

Gravitational waves, despite predicted within the Theory of General Relativity about a century ago, were observed experi-mentally only in the last few years, thanks to the recent advances of the LIGO and Virgo detectors. In this work, we introduce a simple ...

2022

A Signal Peak Separation Index for axisymmetric B-tensor encoding

Jean-Philippe Thiran, Gabriel Girard, Jonathan Rafael Patino Lopez, Marco Pizzolato, Gaëtan Olivier D Rensonnet, Benoît Macq

Diffusion-weighted MRI (DW-MRI) has recently seen a rising interest in planar, spherical and general B-tensor encodings. Some of these sequences have aided traditional linear encoding in the estimation of white matter microstructural features, generally by ...

Springer2021

Stochastic gravitational-wave background from metastable cosmic strings

Valerie Fiona Domcke

A metastable cosmic-string network is a generic consequence of many grand unified theories (GUTs) when combined with cosmic inflation. Metastable cosmic strings are not topologically stable, but decay on cosmic time scales due to pair production of GUT mon ...

IOP Publishing Ltd2021

Chiral Spin-Wave Velocities Induced by All-Garnet Interfacial Dzyaloshinskii-Moriya Interaction in Ultrathin Yttrium Iron Garnet Films

Dirk Grundler, Ping Che, Peng Gao, Haiming Yu, Yuehui Li, Sa Tu, Jilei Chen, Jianyu Zhang, Song Liu, Tao Liu

Spin waves can probe the Dzyaloshinskii-Moriya interaction (DMI), which gives rise to topological spin textures, such as skyrmions. However, the DMI has not yet been reported in yttrium iron garnet (YIG) with arguably the lowest damping for spin waves. In ...

2020

Multi-directional emission and detection of spin waves propagating in yttrium iron garnet with wavelengths down to about 100 nm

Dirk Grundler

We performed broadband spin-wave spectroscopy on 200 nm thick yttrium iron garnet containing arrays of partially embedded magnetic nanodisks. Using integrated coplanar waveguides (CPWs), we studied the excitation and transmission of spin waves depending on ...

AIP American Institute of Physics2018

Ultralight Dark Matter Resonates with Binary Pulsars

Sergey Sibiryakov, Diego Blas Temino

We consider the scenario where dark matter (DM) is represented by an ultralight classical scalar field performing coherent periodic oscillations. We point out that such DM perturbs the dynamics of binary systems either through its gravitational field or vi ...

American Physical Society2017

On the physics of multimode polaritons

Claudéric Ouellet-Plamondon

This thesis is devoted to the study of microcavity polariton systems, in which the strong coupling occurs between more than one exciton or photon modes i.e. multimode polaritons. The first part of this work states the theoretical background of light-matter ...

EPFL2017

Wave propagation in the vicinities of rock fractures under obliquely incident wave

Lyesse Laloui, Jian Zhao, Yang Zou, Jing Li

Though obliquely incident plane wave across rock fractures has been extensively investigated by theoretical analysis, the quantitative identification of each wave emerged from fractures has not been achieved either in numerical simulation or laboratory exp ...

Springer Verlag2016

Seismic response of rock joints under obliquely incident wave

Yang Zou

Seismic response of joints which are found to be ubiquitous in rock masses is of great interest to rock engineers, geophysicists and seismologists. In the past years, wave propagation across rock joints has been the subject of extensive theoretical and exp ...

EPFL2016

Enhanced functionality in magnonics by domain walls and inhomogeneous spin configurations

Dirk Grundler

This paper discusses nanomagnetic structures enabling the manipulation of propagating spin waves. We address in particular how domain walls, or more generally speaking inhomogeneous spin configurations, enhance the control of spin-wave transmission and the ...

2012

A Far-Infrared Polarimeter Diagnostic for the Measurement of the Poloidal Magnetic Field in the TCV Tokamak

Information about the poloidal field inside the plasma and about the current density profile is essential for the understanding of the behavior of tokamak plasmas. The poloidal field outside the plasma edge is easily measured by a set of magnetic coils, wh ...

EPFL2011

Quantum confinement dependence of the energy splitting and recombination dynamics of A and B excitons in a GaN/AlGaN quantum well

Nicolas Grandjean, Jean-François Carlin, Raphaël Butté, Eric Feltin, Dobri Simeonov, Massimo Gurioli

We report the observation of well-resolved A and B excitonic resonances in the reflectivity spectra of a wedged GaN/AlGaN quantum well (QW) with 5% Al content in the barriers for different well thicknesses. For the thicker well cases, the energy splitting ...

2009

Spin Relaxation in InAs Columnar Quantum Dots

We have investigated carrier spin dynamics in InAs columnar quantum dots (CQDs) by time-resolved photoluminescence (PL) measurement. The CQDs were formed by depositing a 1.8 monolayer InAs seed dot layer and a short-period GaAs/InAs superlattice (SL). The ...

2009

Endoscopic low coherence interferometry applied to tri-dimensional contouring of upper airways

Yves Delacrétaz

This thesis presents a novel approach for optical tri-dimensional contouring, requiring only one acquisition to extract a contour depth. It is based on an interferometric setup, using a reduced coherence light source, and is fully adaptable to endoscopic p ...

EPFL2009

Numerical aberrations compensation and polarization imaging in digital holographic microscopy

Tristan Colomb

In this thesis, we describe a method for the numerical reconstruction of the complete wavefront properties from a single digital hologram: the amplitude, the phase and the polarization state. For this purpose, we present the principle of digital holographi ...

EPFL2006

Numerical reconstruction of digital holograms : application to phase-contrast imaging and microscopy

Etienne Cuche

This thesis presents a new method for the numerical reconstruction of digital holograms recorded in the off-axis configuration using a CCD camera. The propagation of the reconstructed wave front, from the hologram plane to an observation plane, is achieved ...

EPFL2000