  We prove in full generality that the $T$-equivariant quantum cohomology of
any flag variety $G/P$ is isomorphic to the coordinate ring of a stratum of the
Peterson scheme associated to the Langlands dual group scheme $G^{\vee}$. This
result was discovered by Dale Peterson but remains unpublished. Our isomorphism
is constructed using Yun-Zhu's isomorphism and Peterson-Lam-Shimozono's
homomorphism.
