We investigate the structure of nodal solutions for coupled nonlinear Schrödinger equations in the repulsive coupling regime. Among other results, for the following coupled system of N equations, we prove the existence of infinitely many nodal solutions which share the same componentwise-prescribed nodal numbers(0.1){−Δuj+λuj=μuj3+∑i≠jβujui2inΩ,uj∈H0,r1(Ω),j=1,…,N, where Ω is a radial domain in Rn for n=2,3 and a bounded interval for n=1, λ>0, μ>0, and β<0. More precisely, let p be a prime factor of N and write N=pB. Suppose β≤−μp−1. Then for any given non-negative integers P1,P2,…,PB, (0.1) has infinitely many solutions (u1,…,uN) such that each of these solutions satisfies the same property: for b=1,...,B, upb−p+i changes sign precisely Pb times for i=1,...,p. The result reveals the complex nature of the solution structure in the repulsive coupling regime due to componentwise segregation of solutions. Our method is to combine a heat flow approach as deformation with a minimax construction of the symmetric mountain pass theorem using a Zp group action index. Our method is robust, also allowing to give the existence of one solution without assuming any symmetry of the coupling.
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