B. Langella

activity

20182020

collaborators

4 papers

math.DS2020

A simple proof for a $C^{\infty}$ Nekhoroshev theorem

Dario Bambusi, Beatrice Langella

We prove a $C^{\infty}$ version of the Nekhoroshev's estimate on the stability times of the actions in close to integrable Hamiltonian systems. The proof we give is a variant of the…

math-ph2019

On the spectrum of the Schrödinger operator on $T^{d}$ : a normal form approach

Dario Bambusi, Beatrice Langella, Riccardo Montalto

In this paper we study the spectrum of the operator \begin{equation} \label{ope} H:=(-Δ)^{M/2}+\mathcal{V}\ , \quad M>0\ , \end{equation} on $L^{2} (R^{d} /Γ)$ , with $Γ$ a maxim…

math-ph2018

Reducibility of non-resonant transport equation on $T^{d}$ with unbounded perturbations

Dario Bambusi, Beatrice Langella, Riccardo Montalto

We prove reducibility of a transport equation on the $d$ -dimensional torus $T^{d}$ with a time quasi-periodic unbounded perturbation. As far as we know this is the first example of a…

math-ph2018

Absolute continuity of the spectrum of coupled identical systems on 1D lattices

Beatrice Langella, Dario Bambusi

We prove that the spectrum of the discrete Schrödinger operator on $ℓ^{2} (Z^{2})$ , $(ψ_{n, m}) \mapsto - (ψ_{n + 1, m} + ψ_{n - 1, m} + ψ_{n, m + 1} + ψ_{n, m - 1}) + V_{n} ψ_{n, m}$ is absolutely continuo…

A simple proof for a C∞ Nekhoroshev theorem

On the spectrum of the Schrödinger operator on Td: a normal form approach

Reducibility of non-resonant transport equation on Td with unbounded perturbations

Absolute continuity of the spectrum of coupled identical systems on 1D lattices

A simple proof for a $C^{\infty}$ Nekhoroshev theorem

On the spectrum of the Schrödinger operator on $T^{d}$ : a normal form approach

Reducibility of non-resonant transport equation on $T^{d}$ with unbounded perturbations