“…For the global existence and scattering of small amplitude solutions, it is necessary to study the dispersion of the operators ∂ t S i , S i and T i with respect to time, and to compare them with nonlinearity, especially to compare the time decay rate with power p. To get a time decay dispersive estimate, Linares [21], and Linares and Scialom [22] [24] for (1.1) with n = 1, and p > 9 2 of Cho and Ozawa [7] for (1.2) with n = 1, and integer p greater than 2 + 1 θ(n,s) of Wang and Chen [39] for (1.2) with n ≥ 2, where θ = In this paper, we improve all the known results under some vanishing condition of initial data at the zero frequency in one dimensional case and extend the results not only on existence and scattering but dispersive estimates to the high dimensional case. Moreover, we also provide a non-existence of nontrivial asymptotically free solutions in the case of small power p, which is a high dimensional version of Theorem 1.3 of [7].…”