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4h
revised Perturbation theory, eigenvalues and eigenvectors for degenerate case (1st order)
added 1 character in body
13h
asked Perturbation theory, eigenvalues and eigenvectors for degenerate case (1st order)
Aug
26
comment Quantum mechanics: clarification about $S \cdot n$
@ToddR Thanks for your answer. I use another book, and in my book there aren't these relations... now I'm going to look for the books that you have suggested...
Aug
26
revised Quantum mechanics: clarification about $S \cdot n$
added 24 characters in body; edited title
Aug
26
comment Quantum mechanics: clarification about $S \cdot n$
@ACuriousMind Please, see my edit
Aug
26
revised Quantum mechanics: clarification about $S \cdot n$
added 472 characters in body
Aug
26
asked Quantum mechanics: clarification about $S \cdot n$
Aug
12
accepted Find the expression of $j_+$ and $j_-$operators
Aug
12
comment Find the expression of $j_+$ and $j_-$operators
Now all is clear! Thanks a lot for your kindness!
Aug
9
comment Find the expression of $j_+$ and $j_-$operators
I'm sorry. I haven't understood, maybe I was not clear in the last question. I'll retry. I can write the matrix $j_+$ in this way: $j_+=\begin {pmatrix} a & b&c\\d&e&f\\g&l&k\end{pmatrix}$. What do I have to put for the element $j+ _{i,l}$? (the element in the row $i$ and column $l$) Many thanks
Aug
9
comment Find the expression of $j_+$ and $j_-$operators
@KyleKanos Ok, I have understood. In the comment to Timaeus' answer I have explained the difficulties that I have met. Next time I'll write them directy in the question. Have a nice day!
Aug
9
comment Find the expression of $j_+$ and $j_-$operators
Thanks a lot, Timaeus! Before posting the question, I tried to find the matrix of $j_+$ using the action of $j_+$ on a state |j, m>: $j_+|j,m>=\hbar \sqrt{(j-m)(j+m+1)} |j,m>$ (I imagine that this formula is analogous to yours, but I haven't understood the origin of 1(1+1).. is it $j(j+1)?$) and I have obtained $j_+|1,1>=\hbar \sqrt 0 |1,1>$; $j_+|1,0>=\hbar \sqrt 2 |1,0>$; $j_+|1,-1>=\hbar \sqrt 2 |1,1>$ my problem is that I don't know to "build" the matrix.... thanks again!
Aug
9
comment Find the expression of $j_+$ and $j_-$operators
@KyleKanos Please, could you explain me in which way I have to ask the question? Do I have to ask only in which way I can find the expression of j+ and j-? (so it will be more respondent to the point "Ask about the specific concept that gives you trouble"..) I have written all the problem only for clarity, I didn't ask to solve the entire problem...
Aug
9
asked Find the expression of $j_+$ and $j_-$operators
Jun
29
comment Multivariate Analysis: how to start
@KyleKanos Oh, you are right, I wasn't precise. I'd like to have something about Programming and Multivariate Analysis because I have to use it with ROOT...
Jun
29
asked Multivariate Analysis: how to start
May
25
accepted photon absorption by atoms causes heat?
May
25
accepted How to measure temperature of a laser cooled sample at picoKelvin temperatures?
May
23
asked Velocity Selective Coherent Population Trapping and recoil limit on temperature
May
22
asked photon absorption by atoms causes heat?