angular momentum quantum numbers
This phenomenon is known as space quantization and was first demonstrated by two German physicists, Otto Stern and Walther Gerlach.
What is space quantization?
: quantization in respect to direction in space the space quantization of an atom in a magnetic field whose quantum states correspond to a limited number of possible angles between the directions of the angular momentum and the magnetic intensity.
Who proposed quantization?
Geometric quantization
One of the earliest attempts at a natural quantization was Weyl quantization, proposed by Hermann Weyl in 1927. Here, an attempt is made to associate a quantum-mechanical observable (a self-adjoint operator on a Hilbert space) with a real-valued function on classical phase space.