# [PHYS G6037] Quantum Mechanics I

- Departments: Physics
- Professors: Norman Christ, Miklos Gyulassy, and Erick Weinberg

You will never get a more straight forward class in your physics education than this one. The first half of the class is very straight forward and mostly review from Physics III. The second half is a do-it-yourself kind of thing. If you want to make sense of the lectures you have to read the book ahead of time, and do practice problems. If you haven't realized yet, the more advanced that the physics courses get, the fewer number of problems they can reasonably ask you on a 75 minute exam. His exam questions come straight from the book, he is up-front about that from the first class. All homework problems are 2 and 3 star difficulty. So if you do every 0 and 1 star problems on your own (total of about 50 problems in Griffiths) chances are you have done all of the questions that will be on the exams. This is not a subject that can be explained through demonstrations or computer graphics, the best way to learn it is to read through the chapters, do all of the 0 and 1 star problems, then read the chapter again. The solutions manual is online (He also acknowledges this in the first class), and there is very little partial credit for homework problems. He doesn't throw any curveballs at you or try to trick you with any questions so take your time when doing homework and try to understand what is going on while using the solutions manual, do all of the above mentioned practice problems and you will learn a lot and do well in the class.

There is not much any professor could do to make the mathematics interesting or easier, his greatest gift to you is not giving you anything that is not fully answered in the text and solutions manual. Many other professors I have taken will throw in their own subjects without much explanation or a book to reference them which just confuse me and I end up not learning them at all.

Very approachable guy, I went to his office hours and admitted that I did not understand what a probability wave function was (the basis of the entire course) and he explained it more simply than he did in class without judgement or being condescending. He really does want everyone to learn the material and do well.

Never went to the recitation, I don't trust TA's. I'm going to be a TA next year, and I wouldn't trust anything I had to say...

#### Workload:

Challenging weekly problem sets (Useful, learn from them), 2 miderms, Final. Class is curved.

Prof. Gyulassy is completely unintelligible. His lectures are disorganized, he skips steps so much that calculations are impossible to follow, he uses metaphors that only he understands ("bookkeeping tools"), and there's no sense of what the big picture is in most of the lectures. His answers to student questions are not helpful; sometimes he states some more things he doesn't explain, usually he just avoids the question. My friend and I understood nothing from him, and managed to learn some QM by reading textbooks/papers and talking to the TA, Andrej Ficnar, who was very helpful and approachable.

That being said, I did appreciate his choice of topics and materials. He covered some of the standard QM, such as path integrals or approximation methods. But he also went into some more exotic topics, like the Wigner formulation of QM, decoherence and path integrals with topological constraints. These were really interesting and challenging topics that, as far as I know, you don't usually get to cover in QM classes. He provided great references - some compilations of notes written by various people, but also some research papers, such as the one in which Zurek first discussed decoherence.

In the end, you do learn a lot if you work hard - but you could learn it much more efficiently if Prof. Gyulassy were able to explain the concepts in class.

#### Workload:

Very heavy; if, like me, you're an undergraduate taking the class, be prepared to spend up to 25 hrs/week on the (almost) weekly problem sets. This includes the time you need to read to catch up with the unintelligible lectures, and the time it takes to figure out what the poorly worded questions actually ask. One in-class open notes midterm, and one 7-hour take-home final. I didn't really like the concept of the 7-hour final. It doesn't feel like a take-home, where you can afford breaks; you just work for 7 hours straight.

Prof. Christ is a very good and EXTREMELY knowledgeable professor. Though I must agree with the other reviewer that not all his proofs are very rigurous, this is not a proof-based math class either. Just like Physics research, it is problem - solving oriented; Quantum Mechanics is a closed field for research, the purpose of this class is to help us get more insight into the physics and the phenomena - and phenomena don't need proofs, they happen. In his class he tries hard to squeeze in as many phenomena as possible - during the first semester, with a more advanced version of the mathematical apparatus in undergrad QM, during the second one with completely new stuff that could never be solved with the undergrad knowledge.

The problems prof. Christ had us solve every week were not always hard, nor always easy - they would alternate. However, each time they actually hid a real physical problem or some new insight (about which you could find out more during his office hours) -to put it this way, I loved all of them.

Though it is true his midterm had some calculations in it that could confuse many, they could be solved in a few lines with some very simple tricks that he did in class. Getting more than 70 however was pretty hard as the last 30 points were the insightful, truly difficult part.

Honestly, I feel his class and his office hours were a great help to me in my global understanding of Physics, and I'm happily taking the second semester of his class.

#### Workload:

weekly beautiful problem set

easy midterm with a pretty difficult ending - that was out of the curve anyway

pretty long final, not excessively tough.

everything can be solved with some insight, unapproachable without.

Professor Christ is a very nice person, always willing to help and take extra time to answer questions, etc. When I went to office hours, he was also very encouraging and smiled a lot, and he would stay late after problem sessions to answer questions. The only problem is that I feel Prof. Christ has some trouble conveying his knowledge to students. Also, the problem sets for this class fluctuated between very easy and quite tricky (I think I stayed up very late trying to figure out how to do a problem on hyperfine structure for the last one) as if he has no sense of the correct difficulty level. I guess I also didn't quite like the system of having homework due on Fridays, with the recitation immediately after (so you realize your mistakes - or get convinced you made one even if you really didn't, although I guess that ingrains it into your memory). Spending Thursday evenings entirely on quantum mechanics ruined my piano lessons for the semester.

As for the lectures, I was a little disappointed about the hand-waviness of the mathematics. I guess I viewed quantum mechanics at the graduate level as a chance to combine math with physics - to view things in terms of symmetries, and use the language of group theory etc. to provide a language with which to do this. In this class, the math just seemed sloppily added to the physics without great motivation; I guess I have a taste for more rigor in math.

The midterm had a low average (35-40%) just because Prof. Christ asked some conceptually straightforward but computational questions (like WKB with five connections). The final seemed a lot easier, so the average was probably higher on that.

Finally, a note on taking graduate classes as an undergraduate: I'm not sure whether to recommend it or advise against it. Certainly the undergraduate quantum mechanics class here is solid (was when I took it with Prof. Kim) so you shouldn't feel pressured to continue immediately with the graduate one (which basically repeats material with a few extra things on representations of the rotation group, etc.). I guess I took it because I like theoretical math as well and was curious what it would be like to take a class combining math and physics - I don't think I really got this in the end.

#### Workload:

Weekly problem set due on Fridays (average of 5 hours of work but fluctuates), midterm, final.

Professor Miklos Gyulassy is the strongest and most transparent lecturer in the department. He is also very gracious to let an undergrad sit in on his

class.

#### Workload:

really hard, really interesting

## Directory Data

Dept/Subj | Directory Course | Professor | Year | Semester | Time | Section |
---|---|---|---|---|---|---|

PHYS / PHYS | PHYS PHYS G6037: Quantum Mechanics I | Miklos Gyulassy | 2012 | Fall | MW / 9:30-10:45 AM | 1 |

PHYS / PHYS | PHYS PHYS G6037: Quantum Mechanics I | Boris Altshuler | 2010 | Fall | MW / 9:00-10:15 AM | 1 |

PHYS / PHYS | PHYS PHYS G6037: Quantum Mechanics I | Boris Altshuler | 2009 | Fall | MW / 9:00-10:15 AM | 1 |

PHYS / PHYS | PHYS PHYS G6037: Quantum Mechanics I | Norman Christ | 2008 | Fall | MW / 9:00-10:15 AM | 1 |

PHYS / PHYS | PHYS PHYS G6037: Quantum Mechanics I | Norman Christ | 2007 | Fall | MW / 9:00-10:15 AM | 1 |

PHYS / PHYS | PHYS PHYS G6037: Quantum Mechanics I | Norman Christ | 2006 | Fall | MW / 9:00-10:15 AM | 1 |

PHYS / PHYS | PHYS PHYS G6037: Quantum Mechanics I | Alfred Mueller | 2004 | Fall | MW / 9:00-10:15 AM | 1 |

PHYS / PHYS | PHYS PHYS G6037: Quantum Mechanics I | Miklos Gyulassy | 2003 | Fall | MW / 9:00-10:15 AM | 1 |

PHYS / PHYS | PHYS PHYS G6037: Quantum Mechanics I | Daniel Kabat | 2002 | Fall | MW / 9:00-10:15 AM | 1 |

PHYS / PHYS | PHYS PHYS G6037: Quantum Mechanics I | Daniel Kabat | 2001 | Fall | MW / 9:00-10:15 AM | 1 |