By introducing new weighted vector fields as multipliers, we derive quantitative pointwise estimates for solutions of defocusing semilinear wave equation in $\mathbb{ R}^{ 1+3}$ with pure power nonlinearity for all $1<p\leq 2$. Consequently, the solution vanishes on the future null infinity and decays in time polynomially for all $\sqrt{ 2}<p\leq 2$. This improves the uniform boundedness result of the second author when $\frac{ 3}{ 2}<p\leq 2$.
Categories: math.AP