Tagged Questions
3
votes
2answers
297 views
Pauli matrix rotations
When doing physics with two-level systems and introducing rotations, a term that appears quite often is the rotation of a pauli matrix by another one:
$e^{- i \sigma_i \theta/2} \sigma_k e^{i ...
2
votes
1answer
318 views
What is the spin rotation operator for spin > 1/2?
For spin $\frac{1}{2}$, the spin rotation operator $R_\alpha(\textbf{n})=\exp(-i\frac{\alpha}{2}\vec{\sigma}\cdot\textbf{n})$ has a simple form:
...
2
votes
1answer
416 views
Help understanding a Magnetic Levitation “Physics Toy”
I was shown a toy, yesterday, which I would like help understanding qualitatively.
A fellow engineer showed me a kit which included three main parts:
1.) A base (black box), approximately 4 ...
12
votes
3answers
557 views
Why does each celestial object spin on its own axis?
AFAIK all the celestial objects have a spin motion around its axis. What is the reason for this? If it must rotate by some theory, what decides it's direction and speed of rotation?
Is there any ...
