# Is the spin of the neutron a quantized property?

In the Quantum Objects chapter it is said that neutrons coming from a nuclear oven and passing through two permanent magnets of opposite polarity hit the surface only at the top and the bottom of it (there is no continuity) because the spin property is quantized and the neutrons trajectory are deviated either at the top or the bottom extremities because the spin axis is either at 90 degree or -90 degree.

My question is: is it possible that the spin axis can exist also at 35, -35, 20, -45... degrees but as soon as the neutron pass through the magnets the spin axis is immediately rotated at 90 or -90 degrees?

That would mean that the spin is not quantized and the neutrons exiting the oven can have a spin axis of random degree, but it will look like the neutrons hitting the surface are only 90 and -90 degrees.

Note by Roberto Rizzo
1 year, 2 months ago

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Great question, Roberto!

I would encourage you to keep going with the course. What you're asking is really a question at the heart of quantum physics!

To give you a little preview: we don't know what angle the spin axis makes before we measure it. What we do know is that, when we do measure it, it takes one of two values: up or down. This is just the behavior of a quantum object, it's an observation about the microscopic world.

For about 100 years, people have been asking the question: what is the orientation of the spin before we measure it? But the answer to this question. belongs to the realm of philosophy, not science, because there's no way to know the answer without measuring. However, as soon as we measure, we're back to two possible outcomes.

Your thinking is spot on, and I believe you'll discover a lot if you continue on in the course. Keep up the good work!

Staff - 1 year, 2 months ago