Quiz solution has been posted. Please check it on page Homework+. It seems that many people got the correct answer for part (a), which is excellent! Note that an observable $\hat O$ will be conserved even if $\hat H$ is not, if $\partial \hat O / \partial t = 0$ and $[\hat O, \hat H] = 0$.

Quiz this Thursday (Oct. 11): as a rule, quiz will follow in the next class after homework has been turned in. Please consult my homework solutions (available for download for homework #1 -- check the Homework+ page) to remind yourself of key concepts that are relevant to the homework that you just turned in. Quiz will be testing those key concepts. Quiz should not take more than 15 minutes or so.

One important correction for homework problem 2(a): plane wave → sine wave. Please consult the updated pdf file in the Homework+ page. – 4:00PM, Oct 08, 2012

Please note that all course materials available from this web site are debugged and updated all the time. All changes are noted, just below the download link. Also, all changes are marked red in pdf files. Please make a habit of checking for them semi-regularly. If changes are made due to observant students pointing out to me the need to make certain changes, then those students may get some benefit of getting a small "lift" at the end of the quarter. For instance, such changes were just made in LN 2. Basically, I record what I perceive as "good student deeds" in my "good deed file" (not only for debugging course materials but also for other things such as asking good questions, leading good discussions and helping other students) and will consult it for a possible bump-up when students' grades lie near borderline at the end of the quarter. – 8:06PM, Oct 06, 2012

(Do keep on voting here.) Please participate in the office hour poll, if you have not done so already. Optionally, if you let me know by email your availability on Monday, Thursday, and Friday, that may be helpful to me, too. This would be helpful especially if you are generally unavailable for my suggested office hours.