Who first proposed the pilot-wave interpretation of quantum mechanics in 1927?

Louis de Broglie first proposed the pilot-wave interpretation of quantum mechanics in 1927. His idea gave particles definite trajectories guided by an accompanying wave, offering a way to explain wave-particle duality without abandoning precisely defined particle positions.

De Broglie's proposal appeared in his 1927 paper on wave mechanics and the atomic structure of matter and radiation. It was later expanded by David Bohm in two 1952 papers, which is why the modern formulation is usually called de Broglie–Bohm theory or Bohmian mechanics.

In this interpretation, the wavefunction evolves according to the Schrödinger equation, while a guiding equation determines how particles move. The theory is deterministic and nonlocal, yet it reproduces the usual statistical predictions of quantum mechanics when particle positions follow the Born-rule distribution.

A common mix-up is choosing David Bohm: Bohm revived and developed the theory decades later, but de Broglie originated the pilot-wave proposal. The double-slit experiment illustrates the central idea: a particle travels through one slit, while the wavefunction through both slits influences its eventual path.