Physics 139B UCSC
Past news of persistent value
There are some forum discussions that relate to the final exam. Please let me know if you have difficulty accessing them.—11:15AM, Dec 10, 2013
There are no news items to post this morning—just doing a virtual “mic check” here. I can almost feel the heat with which all students are working very intently on the exam! Be confident (but don't be over-confident), and get those problems done—You can do it!—12:08PM, Dec 09, 2013
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
One addition and one correction to the exam (both of them marked red in the file.) (1) “spatial” added in Prob 5. (2) “to” → “of” in line 3 of Prob 6.—3:49PM, Dec 07, 2013
The final exam is posted now. Get it by clicking here. Watch this space for any news about the exam.—12:38PM, Dec 06, 2013
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