Physics 139B UCSC
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* A paragraph is added to [[Lecture+#Lecture_Notes|LN 7 (page 8, just before Section 7.5)]]. This may be important for you to consider in doing homework 4.2.—~-''<<DateTime(2013-10-28T14:51:44-0700)>>''-~ * In doing homework 4.4, you would need to use the so-called ''(electric) dipole selection rule'' for the transition: $$ \Delta j = 0, \pm 1 \text{ (but no }j = 0 \rightarrow 0 \text{ transition)},\; \Delta l = \pm 1,\; \Delta m_l = 0, \pm 1.$$ We will be able to derive the last two selection rules later on (or you might be able to prove them already!), but for the first one you will have to wait until you take the graduate level quantum mechanics.—~-''<<DateTime(2013-10-25T18:16:27-0700)>>''-~ * I guess I will see many of you tomorrow during my office hours ('''noon-2PM'''). In addition, please feel free to ask your questions on the forum or by email. '''Good (= sincere) discussions will really protect you in my course''', since (1) you are a learner—I/you/anybody should never expect you be a knower already (although you could be close or already there)—and (2) your willingness to learn will make people (esp., me) respect you very much.—~-''<<DateTime(2013-10-20T20:10:29-0700)>>''-~ * Office hours: Monday <<color(12-2 PM)>>, Thursday, Friday, 1-2 PM, or OBA. (Syllabus updated.)—~-''<<DateTime(2013-10-13T19:34:38-0700)>>''-~ |
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* Homework 4 is due 5 PM, Wednesday, Oct. 30.—~-''<<DateTime(2013-10-25T18:25:08-0700)>>''-~ |
Past news of persistent value
A paragraph is added to LN 7 (page 8, just before Section 7.5). This may be important for you to consider in doing homework 4.2.—2:51PM, Oct 28, 2013
In doing homework 4.4, you would need to use the so-called (electric) dipole selection rule for the transition: $$ \Delta j = 0, \pm 1 \text{ (but no }j = 0 \rightarrow 0 \text{ transition)},\; \Delta l = \pm 1,\; \Delta m_l = 0, \pm 1.$$ We will be able to derive the last two selection rules later on (or you might be able to prove them already!), but for the first one you will have to wait until you take the graduate level quantum mechanics.—6:16PM, Oct 25, 2013
I guess I will see many of you tomorrow during my office hours (noon-2PM). In addition, please feel free to ask your questions on the forum or by email. Good (= sincere) discussions will really protect you in my course, since (1) you are a learner—I/you/anybody should never expect you be a knower already (although you could be close or already there)—and (2) your willingness to learn will make people (esp., me) respect you very much.—8:10PM, Oct 20, 2013
Office hours: Monday 12-2 PM, Thursday, Friday, 1-2 PM, or OBA. (Syllabus updated.)—7:34PM, Oct 13, 2013
There are some discussions of homework problems in the forum. Check them out!—10:46AM, Oct 05, 2013
Welcome back, students!
Past news of purely archival value
Homework 4 is due 5 PM, Wednesday, Oct. 30.—6:25PM, Oct 25, 2013
For problem 4 of homework 2, it would be sufficient to prove that $\langle n^{(0)} | {\underline n}^{(j+1)} \rangle = 0$ for any $j = 0, 1, 2, ...$. The ket $| {\underline n}^{(j+1)} \rangle$ is defined in this image. In the same image, you can find other information. For example, four completely equivalent statements, important for this problem, are noted in the green rectangle. The equivalence of these four statements can be proven based on Eqs. 3.19 and 3.20, alone. This is kind of demonstrated in this image, and you are not required to demonstrate it yourself. Just prove that $\langle n^{(0)} | {\underline n}^{(j+1)} \rangle = 0$ for any $j = 0, 1, 2, ...$ (using the proof by induction).—3:35PM, Oct 14, 2013