  The Feynman path integral plays a crucial role in quantum mechanics, offering
significant insights into the interaction between classical action and
propagators, and linking quantum electrodynamics (QED) with Feynman diagrams.
However, the formulations of path integrals in classical quantum mechanics and
QED are neither unified nor interconnected, suggesting the potential existence
of an important bridging theory that could be key to solving existing puzzles
in quantum mechanics. In this work, we delve into the theoretical consistency,
completeness, and integration with established path integral theories,
revealing this concealed path integral form. This newly uncovered form not only
connects various path integral approaches but also demonstrates its potential
in explaining quantum phenomena like the origin of spin and quantum nonlocal
correlations. It transcends conventional quantum mechanics, proposing a more
profound and fundamental physical principle.
