Concentration phenomena for a fractional Choquard equation with magnetic field

We consider the following nonlinear fractional Choquard equation $${\epsilon }^{2s}(-\mathrm{\Delta }{)}_{A\mathrm{/}\epsilon }^{s}u+V(x)u={\epsilon }^{\mu -N}(\frac{1}{\mathrm{\mid }x{\mathrm{\mid }}^{\mu }}\ast F(\mathrm{\mid }u{\mathrm{\mid }}^2))f(\mathrm{\mid }u{\mathrm{\mid }}^2)uin{\mathbb{R}}^N,$$ where $\epsilon >0$ is a parameter, $s\in (0, 1)$,$0<\mu<2s$,$N\geq 3$,$(-\Delta)^{s}_{A}$ is the fractional magnetic Laplacian, $A:{\mathbb{R}}^N\to {\mathbb{R}}^N$ is a smooth magnetic potential, $V:{\mathbb{R}}^N\to \mathbb{R}$ is a positive potential with a local minimum and $f$ is a continuous nonlinearity with subcritical growth. By using variational methods we prove the existence and concentration of nontrivial solutions for $\epsilon >0$ small enough.