Proper noun
Ehrenfest
A surname
Also see Ehrenfest, P. (1917) "In what way does it become manifest in the fundamental laws of physics that space has three dimensions?" Source: Internet
Classical quantities appear in quantum mechanics in the form of expected values of observables, and as such the Ehrenfest theorem (which predicts the time evolution of the expected values) lends support to the correspondence principle. Source: Internet
Ehrenfest was familiar with Pauli's papers and was quite impressed with them. Source: Internet
Math.Phys. 8, 1538–1545 (1967) ), Ehrenfest made this suggestion in his address on the occasion of the award of the Lorentz Medal to Pauli. Source: Internet
Once the Schrödinger equation was given a probabilistic interpretation, Ehrenfest showed that Newton's laws hold on average: the quantum statistical expectation value of the position and momentum obey Newton's laws. Source: Internet
Proceedings of the Amsterdam Academy20: 200. Ehrenfest also showed that if there are an even number of spatial dimensions, then the different parts of a wave impulse will travel at different speeds. Source: Internet