  Under a Lorentz-transformation, Mie's 1912 gravitational mass behaves
identical as de Broglie's 1923 clock-like frequency. The same goes for Mie's
inertial mass and de Broglie's wave-like frequency. This allows the
interpretation of de Broglie's "Harmony of the Phases" as a "Principle of
Equivalence" for Quantum Gravity. Thus, the particle-wave duality can be given
a realist interpretation. The "Mie-de Broglie" interpretation suggests a
correction of Hamilton's variational principle in the quantum domain. The
equivalence of the masses can be seen as the classical "limit" of the quantum
equivalence of the phases.

General Relativity and Quantum Cosmology