  Quantum Darwinism builds on decoherence theory to explain the emergence of
classical behavior within a quantum universe. We demonstrate that the
differential geometric underpinnings of quantum mechanics provide a uniquely
informative window into the structure of correlations needed to validate
Quantum Darwinism. This leads us to two crucial insights about the emergence of
classical phenomenology, centered around the nullity of quantum discord. First,
we show that the so-called branching structure of the joint state of system and
environment is the only one compatible with zero discord. Second, we prove that
for small, but nonzero discord, the structure of the globally pure state is
arbitrarily close to the branching form. These provide strong evidence that
this class of branching states is the only one compatible with the emergence of
classical phenomenology, as described in Quantum Darwinism.
