activity
20092026
most citedLimiting absorption principle for the dissipative Helmholtz equation

46 citations · 144 across the 25 of their papers we have counts for

collaborators

28 papers

math.SP2026

Two escape rates for negative eigenvalues of quantum graphs with a shrinking core

Gregory Berkolaiko, Denis Borisov, Marshall King +1

We study the negative spectrum of the Laplacian on a metric graph with general vertex matching conditions and with two length scales: a compact core whose edges have length of orde…

math.AP2026

Semigroup decay for the wave equation with unbounded damping

Antonio Arnal, Borbala Gerhat, Julien Royer +1

We study the damped wave equation with a damping coefficient which is possibly singular and unbounded at infinity. In general, zero belongs to the spectrum of the corresponding gen…

math.AP2023

A minimal mass blow-up solution on a nonlinear quantum star graph

François Genoud, Stefan Le Coz, Julien Royer

We construct a finite-time blow-up solution to the mass-critical focusing nonlinear Schrödinger equation on a metric star graph with an arbitrary number of edges. We show that all…

math.OC2022

Null-controllability properties of the generalized two-dimensional Baouendi-Grushin equation with non-rectangular control sets

Jérémi Dardé, Armand Koenig, Julien Royer

We consider the null-controllability problem for the generalized Baouendi-Grushin equation on a rectangular domain. Sharp…

math-ph2022

On Duclos-Exner's conjecture about waveguides in strong uniform magnetic fields

Enguerrand Bon-Lavigne, Loïc Le Treust, Nicolas Raymond +1

We consider the Dirichlet Laplacian with uniform magnetic field on a curved strip in two dimensions. We give a sufficient condition ensuring the existence of the discrete spectrum…

math.SP2022

Spectrum of the wave equation with Dirac damping on a non-compact star graph

David Krejcirik, Julien Royer

We consider the wave equation on non-compact star graphs, subject to a distributional damping defined through a Robin-type vertex condition with complex coupling. It is shown that…

math.AP2021

Energy decay for a system of Schr{ö}dinger equations in a wave guide

Radhia Ayechi, Ilhem Boukhris, Julien Royer

We prove exponential decay for a system of two Schr{ö}dinger equations in a wave guide, with coupling and damping at the boundary. This relies on the spectral analysis of the corre…

math.AP2021

Low frequency asymptotics and local energy decay for the Schr{ö}dinger equation

Julien Royer

We prove low frequency resolvent estimates and local energy decay for the Schr{ö}dinger equation in an asymptotically Euclidean setting. More precisely, we go beyond the optimal es…

math-ph2019★ 12 cited

Spectrum of a non-selfadjoint quantum star graph

Gabriel Riviere, Julien Royer

We study the spectrum of a quantum star graph with a non-selfadjoint Robin condition at the central vertex. We first prove that, in the high frequency limit, the spectrum of the Ro…

math-ph2019★ 2 cited

Absence of embedded eigenvalues for translationally invariant magnetic Laplacians

Nicolas Raymond, Julien Royer

Translationnally invariant bidimensional magnetic Laplacians are considered. Using an improved version of the harmonic approximation, we establish the absence of point spectrum und…

math.AP2018★ 8 cited

Stability of Standing Waves for a Nonlinear Klein-Gordon Equation with Delta Potentials

Elek Csobo, François Genoud, Masahito Ohta +1

In this paper, we study local well-posedness and orbital stability of standing waves for a singularly perturbed one-dimensional nonlinear Klein-Gordon equation. We first establish…

math-ph2017★ 2 cited

Energy decay for the Klein-Gordon equation with highly oscillating damping

Julien Royer

We consider the free Klein-Gordon equation with periodic damping. We show on this simple model that if the usual geometric condition holds then the decay of the energy is uniform w…

math-ph2017

Energy decay and diffusion phenomenon for the asymptotically periodic damped wave equation

Romain Joly, Julien Royer

We prove local and global energy decay for the asymptotically periodic damped wave equation on the Euclidean space. Since the behavior of high frequencies is already mostly underst…

math-ph2017

Reduction of dimension as a consequence of norm-resolvent convergence and applications

David Krejcirik, Nicolas Raymond, Julien Royer +1

This paper is devoted to dimensional reductions via the norm resolvent convergence. We derive explicit bounds on the resolvent difference as well as spectral asymptotics. The effic…

math-ph2016

Energy Decay in a Wave Guide with Dissipation at Infinity

Mohamed Malloug, Julien Royer

We prove local and global energy decay for the wave equation in a wave guide with damping at infinity. More precisely, the absorption index is assumed to converge slowly to a posit…

math.SP2016

Non-accretive Schrödinger operators and exponential decay of their eigenfunctions

David Krejcirik, Nicolas Raymond, Julien Royer +1

We consider non-self-adjoint electromagnetic Schrödinger operators on arbitrary open sets with complex scalar potentials whose real part is not necessarily bounded from below. Unde…

math-ph2016

Local Energy Decay and Diffusive Phenomenon in a Dissipative Wave Guide

Julien Royer

We prove the local energy decay for the wave equation in a wave guide with dissipation at the boundary. It appears that for large times the dissipated wave behaves like a solution…

math.AP2015

On the Cauchy problem and the black solitons of a singularly perturbed Gross-Pitaevskii equation

Isabella Ianni, Stefan Le Coz, Julien Royer

We consider the one-dimensional Gross-Pitaevskii equation perturbed by a Dirac potential. Using a fine analysis of the properties of the linear propagator, we study the well-posedn…

math-ph2015★ 7 cited

Local decay for the damped wave equation in the energy space

Julien Royer

We improve a previous result about the local energy decay for the damped wave equation on R^d. The problem is governed by a Laplacian associated with a long range perturbation of t…

math-ph2015★ 6 cited

Local energy decay and smoothing effect for the damped Schr{ö}dinger equation

Moez Khenissi, Julien Royer

We prove the local energy decay and the smoothing effect for the damped Schr{ö}dinger equation on R^d. The self-adjoint part is a Laplacian associated to a long-range perturbation…

math.SP2014★ 2 cited

Mourre's method for a dissipative form perturbation

Julien Royer

We prove uniform resolvent estimates for an abstract operator given by a dissipative perturbation of a self-adjoint operator in the sense of forms. For this we adapt the commutator…

math-ph2014★ 10 cited

Exponential decay for the Schr{ö}dinger equation on a dissipative waveguide

Julien Royer

We prove exponential decay for the solution of the Schr{ö}dinger equation on a dissipative waveguide. The absorption is effective everywhere on the boundary but the geometric contr…

math.AP2014★ 8 cited

Sharp low frequency resolvent estimates on asymptotically conical manifolds

Jean-Marc Bouclet, Julien Royer

On a class of asymptotically conical manifolds, we prove two types of low frequency estimates for the resolvent of the Laplace-Beltrami operator. The first result is a uniform $ L^…

math-ph2013★ 36 cited

Local Energy Decay for the Damped Wave Equation

Jean-Marc Bouclet, Julien Royer

We prove local energy decay for the damped wave equation on R^d. The problem which we consider is given by a long range metric perturbation of the Euclidean Laplacian with a short…