Yonggeun Cho, Gyeongha Hwang, Changhun Yang. Source: Advances in Differential Equations, Volume 23, Number 9/10, 649--692.Abstract:
In this paper, we study 3-d Hartree type fractional Schrödinger equations: $$ i\partial_{t}u-\vert\nabla\vert^{\alpha}u = \lambda \left ( |x|^{-\gamma} *\vert u\vert^{2} \right ) u,\;\;1 < \alpha < 2,\;\;0 < \gamma < 3,\; \lambda \in \mathbb R \setminus \{0\}. $$ In [7] it is known that no scattering occurs in $L^2$ for the long range ($0 < \gamma \le 1$). In [4, 10, 8] the short-range scattering ($1 < \gamma < 3$) was treated for the scattering in $H^s$. In this paper, we consider the critical case ($\gamma = 1$) and prove a modified scattering in $L^\infty$ on the frequency to the Cauchy problem with small initial data. For this purpose, we investigate the global behavior of $x e^{it |\nabla|^\alpha } u$, $x^2 e^{it |\nabla|^\alpha } u$ and $ \langle\xi\rangle ^5 \widehat{e^{it |\nabla|^\alpha } u}$. Due to the non-smoothness of $ |\nabla|^\alpha $ near zero frequency the range of $\alpha$ is restricted to $(\frac{17}{10}, 2)$.