Normalized solutions of coupled Sobolev critical Schrodinger equations with mass subcritical couplings
We are concerned with qualitative properties of positive solutions to the following coupled Sobolev critical Schrödinger equations $$ \begin{cases} -Δu+λ_1 u=μ_1|u|^{2^*-2}u+να|u|^{α-2}|v|^βu ~\hbox{in}~ \R^N,\\ -Δv+λ_2 v=μ_2|v|^{2^*-2}v+νβ|u|^α|v|^{β-2}v ~\hbox{in}~ \R^N \end{cases} $$ subject to the mass constraints $\int_{\mathbb{R}^N}|u|^2 \ud x=a^2$ and $\int_{\mathbb{R}^N}|v|^2 \ud x=b^2$, where, $a>0,\,b>0,\,N=3,4$ and $2^*:=\frac{2N}{N-2}$ is the Sobolev critical exponent. The main purpose of this paper is focused on the mass mixed case, i. e., $ α>1,β>1,α+β<2+\frac{4}{N}$. For some suitable small $ν>0$, we show that the above system admits two positive solutions, one of which is a local minimizer, and another one is a mountain pass solution. Moreover, as $ν\to0^+$, asymptotic behaviors of solutions are also considered. Our result gives an affirmative answer to a Soave's type open problem raised by Bartsch {\it et al.} (Calc. Var. Partial Differential Equations 62(1), Paper No. 9, 34, 2023).