Symmetry breaking and multiplicity for supercritical elliptic Hamiltonian systems in exterior domains

Abstract

We consider positive solutions of the following elliptic Hamiltonian systems \begin{equation} \left\{ \begin{aligned} -\Delta u+u&=a(x)v^{p-1}~~~\text{in}~~A_R\\ -\Delta v+v&=b(x)u^{q-1}~~~\text{in}~~A_R~~~~~~~~~~~~~~~~~(0.1)\\ u, v&>0~~~~~~~~~~~~~~~\text{in}~~A_R\\ u=v&=0~~~~~~~~~~~~~~~\text{on}~~\partial A_R, \end{aligned} \right. \end{equation} where $A_R=\{x\in\mathbb{R}^{N}: |x|>R\}$, $R>0$, $N>3$, and $a(x)$ and $b(x)$ are positive continuous functions. Under certain symmetry and monotonicity properties on $a(x)$ and $b(x)$, we prove that (0.1) has a positive solution for $(p,q)$ above the standard critical hyperbola, that is, $\frac{1}{p}+\frac{1}{q}<1-\frac{2}{N}$, enjoying the same symmetry and monotonicity properties as the weights $a$ and $b$. In the case when $a(x)=b(x)=1$, our result ensures multiplicity as it provides $\Big\lfloor \frac{N}{2}\Big\rfloor-1$ (being $\lfloor \frac{N}{2}\rfloor$ the floor of $\frac{N}{2}$) non-radial positive solutions provided that \begin{equation} (p-1)(q-1)>\Big(1+\frac{2N}{\Lambda_H}\Big)^{2}\Big(\frac{q}{p}\Big), \end{equation} where $\Lambda_H$ is the optimal constant in Hardy inequality for the domain $A_R$.