Spin of a particle : What exactly is and what is not !

Following notes are created to give an insight about a spin quantum number and its physical description

Some points that are mostly misunderstood or interpreted by many people about the spin of a particle or more conveniently the spin quantum number

• Spin is not actually a self-rotation of an electron around its rotation axes. It is an intrinsic degree of freedom independent from the coordinates (just like the mass of a particle) !!!
• When we consider fermionic particles(such as electron or proton), we consider that they have +-1/2 spin quantum number. Thus, we mostly use up and down terms since m(+-1/2) particles are easy to define that way. But there is no point of an arrow for the spin that can be defined as up or down.
• Even students graduated from physics and unfortunately many physicists point with their fingers up or down when trying to explain the spin to other people. Mostly they use it because it makes it easier to understand, however, if you do not explain this fact about the spin, then commonly misunderstood movement of hands can, in time, replace the true meaning of it.
• Let's think! (after all this whole blog is about finding some time to think!) What about the spin +-5/2 particles? Are they up-up-down or down-down-up ... etc. How should we point our fingers then? -------> Of course NOT!
• These terms are mostly made for a better understanding of "the states that the particles are in".
• The correct way to point (or use your hands) while talking about a spin of a particle should not be pointing your finger up or down!
• Last classical calculation in the notes clearly proves the fact that you can not think electron as a self-rotating spinning ball.