By: Dr. Fabiano de Abreu Agrela Rodrigues
I imagine a room that I will call the atom. I am there inside this room analyzing the quantum interaction between the materials that make up protons, neutrons and electrons, as well as the forces that interact between them. I perceive the spins as small compasses in each particle, influencing their “affinities” and “repulsions” and how they organize themselves in space. It is as if each particle were a magnet, interacting with the others according to the direction of its internal compass.
Another analogy would be to imagine the spins as the poles of a planet, but without the planet. Just think of the poles.
Imagine a magnet, where the electrons spin internally in the same direction so that the phenomenon of magnetism occurs. The spin would be like this magnet, defining the direction of the magnetic field, which we can call “up” or “down”. If external influences, such as another magnet, change the orientation of this magnet, it will maintain the new direction after the change.
Similarly, spin can be viewed as the poles of a magnet.
Both spin and classical rotation are associated with angular momentum, a physical quantity that describes the tendency of an object to continue spinning. Just as a spinning object has an axis of rotation with a defined direction, spin describes the direction of the particle’s intrinsic angular momentum.
We can think of spin as the axis, not the direction, not the shape, not the speed, but simply the axis in spacetime. And the axis represents position.
The concept of spin emerged as an idea when reflecting on the definition of the position and orientation of particles in the universe. It presents itself as a fundamental element of the structure of space-time, and not just as an individual property of particles.
“Imagine that I am in space, in a vacuum, with no force or matter other than a billiard ball with the number 8 on it. I, hypothetically, do not exist and I am part of the analogy. I spin this billiard ball clockwise at 30 degrees. It would continue to spin forever in that direction, with the number 8 pointing at 30 degrees. If I could remove the spin, hypothetically, the number 8 would lose reference to the direction of its axis of rotation and would become ungoverned in relation to space-time.”
We can say that spin is a definition of “thing” in the subjective sense, considering “thing” as the elementary particle itself.
