PHY 401- Fall 2008
University of Maryland, College Park

Instructor: Prof. Paulo Bedaque
Physics Building 4103

Grader:  Tung-Chang Liu

The two first lectures (September 3rd and 5th) will be taught by Michael Buchoff and Aleksey Cherman. The regular instructor (Paulo Bedaque) will be back on Monday, September 8th)

Lecture hours: Mondays and Fridays, 10:00 am – 10:50am

                          Wednesdays, 10:00 am – 11:50am 

Office hours: Mondays and Fridays, 10:50 am – 11:50am or other times previously arranged


Textbook: We will not follow closely any book but the closest one is "Introduction to Quantum Mechanics", by David J. Griffiths (any edition will do). Many other texts, most of them found in the library, can also be very useful. You are encouraged to explore. For the historical part (black body radiation, Bohr atom, ...) one recommendation is "Quantum Physics of Atoms, Molecules, Solids, Nuclei, and Particles" by R. Eisberg and R. Resnick. Keep inmind that Eisberg&Resnick cover MUCH more material, in depth and breadth, that we will. You will also probably enjoy reading the cartoon book "Introducing Quantum Theory" by J. P. McEvoy. Don't let it fool you, this book has content ! it is an ideal reading for before the class starts.


I noticed in that many (most?) students in the previous years had difficulties in the class due to improper mathematical background as opposed to the inherent difficult of the new material. As a remedy, the first two lectures will be devoted to 1) complex numbers and 2) differential equations. The material of the “complex number” lecture is well described in chapter 3 of the free (and excellent) textbook “Mathematical Tools for Physics”, by James Nearing, which can be downloaded from this site.
Also, I wrote a very short summary (pspdf) you may find useful. What we will need about differential equations before the class starts is very minimal and there is also a summary (ps, pdf) I wrote. As the class progresses more mathematics will be needed and I’ll discuss them during the semester. In particular, a good knowledge of linear algebra, both in its abstract and computational aspects, is essential for the full understanding of quantum mechanics. Again, Nearing’s book (chapters 6 and 7) is a good place to start.

Grading policy: There will be three tests, each one worth 30% of the final grade. The remaining 10% will be determined by the periodic homework. Possible make up tests can be offered only to students with a valid health reason (with doctor’s note) and should be arranged as soon as possible. Students who cannot attend a test due to religious reasons should contact the instructor as soon as possible to discuss an alternative. Grades will be posted on Blackboard.


Honor code: Students are encouraged to discuss the homework among themselves but they should be prepared to explain every step to the instructor, if asked. No collaboration, notes, books or calculators are allowed during the tests.


homework 1   solution

homework 2 , Mathematica code  solutionsolution to the numerical part

homework_3 solution (courtesy of T. C. Liu)

homework 4 solution 

homework_5  solution

homework 6 solution


homework_8 solution


First midterm: 1st part October 6th, 10:00 am to 10:50 am, 2nd part October 8th 10:00 am to 10:50 am    solution 

Second midterm:  November 26th, 10:00am to 11:50am solution 

Final:  December 20th, 8:00 am to 10:00 am at Physics Building 1201 final  solution

Lecture Notes

Notes on the historical development of quantum mechanics (short summary).  
And some more on the Bohr atom and de broglie hypothesis.
two incredibly short summaries of quantum mechanics: one in the old notation and another with bras and kets.

Interesting links

Potential barriers

Movies showing wave packets colliding with walls, etc..

Applet showing a wave packet tunneling through a barrier.

Blackbody radiation

You can buy your own blackbody here

A nice figure of the blackbody spectrum.

The Universe as a blackbody: the spectrum from COBE and the tiny variations of the temperature with the direction in space. More about the COBE sattelite.

Even NASA scientists know that holes are really dark, even in Mars.

Photoelectric effect

An applet that simulates the photoelectric effect. Try  varying the different handles and predicting the outcome !

Founding Fathers

Video of the Solvay Conference of 1927 showing all the Quantum Mechanics Founding Fathers during their breaks. Eisntein And Schroedinger did not seem happy about all that talk about probabilities.


One change in relation to the previous years is that I will not start discussing the history of how quantum mechanics was discovered/invented. But I plan to discuss that in the middle of the semester. Our tentative syllabus is

 Non-determinism in quantum mechanics: wave function and its statistical    interpretation (with a quick review of probabilities); Schroedinger equation; Momentum distribution and a first look at the uncertainty principle

Infinite square well: transmission and reflection

Harmonic oscillator

Free particle

Delta function potential

Finite square well: tunneling

Blackbody radiation

Compton effect

Photoelectric effect

Bohr atom

Review of linear algebra; Dirac notation

Observables and operators; Eigenfunctions and eigenvlaues

Generalized statistical interpretation

Two-level systems

Schroedinger equation in spherical coordinates

Angular momentum

Hydrogen atom


Bosons and fermions; Applications to atoms, nuclei, solids, …