What is Spin? | Quantum Mechanics
Why Physics Stack Exchange recommends it
Physics Stack Exchange users link it as an intuitive entry point to spin and the Stern-Gerlach experiment, and sometimes as a reference when questioning its magnet analogy.
Recommended by 1 people across 1 different months, 2018 to 2022.
What it is
A 10-minute explainer from the Looking Glass Universe channel that introduces quantum spin through the Stern-Gerlach experiment, using an analogy with tiny magnets. It covers why measured spin comes out quantized as only up or down, and ends with research questions for further study.
What people said
Recommends phywn8 · 2022-05 · Physics Stack Exchange · on “Observing attraction between parallel wires from two perspectives”
That doesn't seem right. Electricity is basically charged particles in motion... Also, whenever a charged particle moves, it crerates a magnetic field: [this video] Watch this video aswell: [LINK]
Cites user218113 · 2018-08 · Physics Stack Exchange · on “Don't the magnets slip and turn in Stern-Gerlach experiment, if their orientation is not aligned with the applied magnetic field?”
I was watching two videos on YouTube: In this video [this video] , there is an attempt to explain what spin is, using analogy of magnets. But here it is shown that magnets which are not aligned with magnetic field stay like that and experience less force than the magnets which are aligned with the field. But in this video [LINK] , it is said that magnets experience a force, which is called dipole moment, which produces a torque, thereby turning the magnet. So in the first video the magnets, which are not aligned should turn right?
Cites Sashwat Tanay · 2021-01 · Physics Stack Exchange · on “Stern-Gerlach apparatus measures the magnetic moment. How to measure spin?”
Here is my understanding of it. I will take the help of two widely read books: Griffiths QM - 2nd ed. (Ref. 1) and Sakurai's Modern Quantum Mechanics - revised ed. (Ref. 2) PART 1: WHY ARE ELECTRONS CONSIDERED TO HAVE A SPIN ANGULAR MOMENTUM? Since electrons respond to a magnetic field, they are said to have a magnetic moment, and a Hamiltonian $H = - \vec{\mu} \cdot \vec{B}$ is lifted from classical physics, with $\mu$ being the magnetic moment. Under this $H$ , the e- have been found to rotate (or precess; i.e. Larmor precession). It is simply a precession of the magnetic moment which is detectable when placed between the Stern-Gerlach magnets. This precession has been worked out in Exampl