Growth of Sobolev norms in the cubic defocusing nonlinear Schrödinger equation

M Guardia, V Kaloshin - Journal of the European Mathematical Society, 2015 - ems.press
We consider the cubic defocusing nonlinear Schrödinger equation on the two-dimensional
torus. Fix s> 1. Recently Colliander, Keel, Staffilani, Tao and Takaoka proved the existence …

KAM for the quantum harmonic oscillator

B Grébert, L Thomann - Communications in mathematical physics, 2011 - Springer
In this paper we prove an abstract KAM theorem for infinite dimensional Hamiltonians
systems. This result extends previous works of SB Kuksin and J. Pöschel and uses recent …

Rational normal forms and stability of small solutions to nonlinear Schrödinger equations

J Bernier, E Faou, B Grebert - Annals of PDE, 2020 - Springer
We consider general classes of nonlinear Schrödinger equations on the circle with nontrivial
cubic part and without external parameters. We construct a new type of normal forms …

On the cubic lowest Landau level equation

P Gérard, P Germain, L Thomann - Archive for Rational Mechanics and …, 2019 - Springer
We study dynamical properties of the cubic lowest Landau level equation, which is used in
the modeling of fast rotating Bose–Einstein condensates. We obtain bounds on the decay of …

On reducibility of quantum harmonic oscillator on with quasiperiodic in time potential

B Grébert, E Paturel - Annales de la Faculté des sciences …, 2019 - afst.centre-mersenne.org
We prove that a linear d-dimensional Schrödinger equation on Rd with harmonic potential|
x| 2 and small t-quasiperiodic potential i∂ tu−∆ u+| x| 2u+ εV (tω, x) u= 0, x∈ Rd reduces to …

Growth of Sobolev norms for the quintic NLS on T2

E Haus, M Procesi - Analysis & PDE, 2015 - msp.org
We study the quintic nonlinear Schrödinger equation on a two-dimensional torus and exhibit
orbits whose Sobolev norms grow with time. The main point is to reduce to a sufficiently …

KAM for the Klein Gordon equation on

B Grébert, E Paturel - Bollettino dell'Unione Matematica Italiana, 2016 - Springer
Recently the KAM theory has been extended to multidimensional PDEs. Nevertheless all
these recent results concern PDEs on the torus, essentially because in that case the …

Birkhoff normal forms for Hamiltonian PDEs in their energy space

J Bernier, B Grébert - Journal de l'École polytechnique …, 2022 - numdam.org
We study the long time behavior of small solutions of semi-linear dispersive Hamiltonian
partial differential equations on confined domains. Provided that the system enjoys a new …

On weakly turbulent solutions to the perturbed linear harmonic oscillator

E Faou, P Raphaël - American Journal of Mathematics, 2023 - muse.jhu.edu
We introduce specific solutions to the linear harmonic oscillator, named bubbles. They form
resonant families of invariant tori of the linear dynamics, with arbitrarily large Sobolev norms …

Long time dynamics for generalized Korteweg–de Vries and Benjamin–Ono equations

J Bernier, B Grébert - Archive for Rational Mechanics and Analysis, 2021 - Springer
We provide an accurate description of the long time dynamics of the solutions of the
generalized Korteweg–De Vries and Benjamin–Ono equations on the one dimension torus …