Multiplicity result for a mass supercritical NLS with a partial confinement
Louis Jeanjean, Linjie Song
TL;DR
This work proves the existence of two distinct normalized bound states for a mass-supercritical NLS with partial confinement in ${\mathbb R}^3$: a ground state and a mountain-pass state, for small mass $\mu$. The authors devise a non-perturbative scheme by first solving the constrained problem on large balls ${B_R}$, exploiting symmetry to gain compactness, and then passing to the limit $R\to\infty$ to obtain two positive critical points of the energy on the mass sphere ${S_\mu}$. A key compactness result using symmetry and a Liouville-type argument ensures strong convergence in $H$ away from the critical energy threshold, enabling a rigorous limit passage and the construction of the two solutions on the full space. Moreover, the paper provides detailed asymptotic descriptions as $\mu\to0$, including precise behavior of the Lagrange multipliers and the profiles of the two solutions, and discusses orbital stability properties. Overall, the work extends non-perturbative multiplicity results for NLS with partial confinement and highlights the utility of bounded-domain approximation combined with symmetry-based compactness.
Abstract
We consider an NLS equation in $\mathbb{R}^3$ with partial confinement and mass supercritical nonlinearity. In Bellazzini, Boussaid, Jeanjean and Visciglia (Comm. Math. Phys. 353, 2017, 229-251) for such a problem, a solution with a prescribed $L^2$ norm was obtained, as a local minima, and the existence of a second solution, at a mountain pass energy level, was proposed as an open problem. We give here a positive, non-perturbative, answer to this problem. Our solution is obtained as a limit of a sequence of solutions of corresponding problems on bounded domains of $\mathbb{R}^3$. The symmetry of solutions on bounded domains is used centrally in the convergence process.
