Besides quantizing light energy and seeing its interchangeability with matter, E = mc2, Einstein was first to see many of the most fundamental aspects of quantum physics – the quantal derivation of the blackbody radiation law, nonlocality and instantaneous action-at-a-distance (1905), the internal structure of atoms (1906), wave-particle duality and the “collapse” of the wave aspect (1909), transition probabilities for emission and absorption processes that introduce indeterminism whenever matter and radiation interact, making quantum mechanics a statistical theory (1916-17), the indistinguishability of elementary particles with their strange quantum statistics (1925), and the nonseparability and entanglement of interacting identical particles (1935).
It took the physics community eighteen years to accept Einstein’s light-quantum hypothesis. He saw wave-particle duality fifteen years before deBroglie, Schrödinger, Heisenberg, and Bohr. He saw indeterminism a decade before the Heisenberg uncertainty principle. He saw nonlocality as early as 1905, presenting it formally in 1927, but was ignored. In the 1935 Einstein-Podolsky-Rosen paper, he added nonseparability, which was dubbed “entanglement” by Schrödinger.
We show that there was a glimpse of wave-particle duality even in Einstein’s “very revolutionary” 1905 light-quantum hypothesis paper.