Classical Mechanics and the Old Quantum Theory

Marco Giliberti, Luisa Lovisetti

L. E. Ballentine

Ian Colin Percival

For many physicists who live on intimate terms with atoms, molecules, solids or particles, classical mechanics is a necessary evil, sometimes needed to provide a Hamiltonian or Lagrangian, and hastily abandoned when it has served this purpose. It was not always so: those who worked with Niels Bohr and Max Born in the early 1920s had no quantum mechanics to turn to: they had to do their best with classical mechanics and the old quantum theory.

N. Rosen

Patrick A. Heelan

Xueheng Wei

Quantum mechanics is more creativity than relativity theory. How does quantum mechanics impact the paradigm of classical physics? Although both Einstein and Bohr raised relatively vague questions about the old paradigm of physics, such as Einstein's question about differential equations and Bohr's use of "blind crutches" to question the cognitive function of experimental instruments. But there has been no outright skepticism.