Explicit construction of stationary discs and its consequences for nondegenerate quadrics

We give an explicit construction of a key family of stationary discs attached to a nondegenerate model quadric in ${\mathbb{C}}^N$ and derive a necessary condition for which (each lift) of those stationary discs is uniquely determined by its $1$-jet at a given point via a local diffeomorphism. This unique $1$-jet determination is a crucial step to deduce $2$-jet determination for CR automorphisms of generic real submanifolds in ${\mathbb{C}}^N$.