Soft theorems in maximally supersymmetric theories

In this paper we study the supersymmetric generalization of the new soft theorem which was proposed by Cachazo and Strominger recently. At tree level, we prove the validity of the super soft theorems in both ${\cal N}=4$ super-Yang-Mills theory and ${\cal N}=8$ supergravity using super-BCFW recursion relations. We verify these theorems exactly by showing some examples.