Local uniqueness of multi-peak positive solutions to a class of fractional Kirchhoff equations
Zhipeng Yang
TL;DR
The paper analyzes a singularly perturbed fractional Kirchhoff equation and proves the existence of multi-peak positive solutions concentrating near prescribed points where the potential attains favorable values. A Lyapunov–Schmidt reduction is used to reduce the infinite-dimensional problem to a finite-dimensional one, yielding a coupled system as the limiting equation for the peak profiles. Under mild conditions on the potential, the authors show both existence and precise concentration behavior; with additional assumptions, they establish local uniqueness of these multi-peak states via a local Pohozaev identity. This work reveals a novel phenomenon where the limiting behavior of multi-peak solutions is governed by a coupled system rather than a single fractional Kirchhoff equation, highlighting the nonlocal nature of the Kirchhoff term in the fractional setting.
Abstract
This paper has two main purposes. In the first part, combining the nondegeneracy of the ground state with the Lyapunov--Schmidt reduction method, we prove the existence of multi-peak positive solutions to the singularly perturbed problem \[\Big(\varepsilon^{2s}a+\varepsilon^{4s-N} b\int_{\mathbb{R}^{N}}|(-Δ)^{\frac{s}{2}}u|^2\,dx\Big)(-Δ)^s u+V(x)u=u^p\quad \text{in }\mathbb{R}^{N},\] for all sufficiently small $\varepsilon> 0$, under the assumptions $2s<N<4s$, $1<p<2^*_s-1$, and some mild conditions on the potential $V$. The main difficulty comes from the interplay between the nonlocal operator $(-Δ)^s$ and the nonlocal Kirchhoff term, which makes the corresponding limiting problem a coupled system of partial differential equations rather than a single fractional Kirchhoff equation. In the second part, under additional assumptions on $V$, we establish the local uniqueness of positive multi-peak solutions by means of a local Pohozǎev identity.
