Local controllability of the bilinear 1D Schr{\"o}dinger equation with simultaneous estimates

TL;DR

This paper proves small-time local controllability of the 1D bilinear Schrödinger equation around the ground state under weaker assumptions, providing simultaneous control estimates in multiple spaces using a new trigonometric moment problem result.

Contribution

It introduces a novel controllability result under weaker conditions and establishes simultaneous control estimates via a new approach to trigonometric moment problems.

Findings

Controllability achieved under weaker nondegeneracy assumptions.

Simultaneous control estimates in multiple functional spaces.

Extension of controllability results to nonlinear dynamics.

Abstract

We consider the 1D linear Schr{\"o}dinger equation, on a bounded interval, with Dirichlet boundary conditions and bilinear scalar control. The small-time local exact controllability around the ground state was proved in [BeaLau10], under an appropriate nondegeneracy assumption. Here, we work under a weaker nondegeneracy assumption and we prove the small-time local exact controllability in projection, around the ground state, with estimates on the control (depending linearly on the target) simultaneously in several spaces. These estimates are obtained at the level of the linearized system, thanks to a new result about trigonometric moment problems. Then, they are transported to the nonlinear system by the inverse mapping theorem, thanks to appropriate estimates of the error between the nonlinear and the linearized dynamics.