California Institute of Technology

Division of Physics, Mathematics and Astronomy

Physics 12b - Introduction to Quantum Physics, Jan-Mar 2008.

Physics 12b is a 10-week introduction to quantum physics for students planning to major in physics, astronomy, or related fields.

from Quantum Mechanics on the Macintosh, Brandt & Dahmen, Springer-Verlag, 1991.

Announcements:

• Congratulations on a successful term; you are now quantum mechanics! I can tell that the final was maybe a bit too easy, but also that you all worked very, very hard this term. Job well done!
• Please fill out the TQFR, and I welcome any comments you might have on the course. I'm also available if you ever want to talk about physics, research, etc.
• Please let me know if there are any errors in the scores we have for you, which will be stapled into the final exams that will be returned to the Physics 12 OUT box ASAP.
• Have a great spring break, and enjoy Physics 12c! (I will be teaching 12c next year, and welcome any advice).
  Cheers, Alan Weinstein (for the rest of the Ph12b team, Nate, Miguel, Prabha, Heywood).

Instructor: Prof. Alan J. Weinstein

Office: 260 Lauritsen
Mail Code: 256-48
Phone: x6682
E-mail: ajw AT caltech.edu
I do not have regular office hours; email me!

Prerequisites:

Math 1abc or equivalent (differential equations, complex numbers, ...)
Physics 1abc, or equivalent (mechanics, special relativity, electromagnetism)
Physics 2a or Physics 12a: Waves!

Lectures:

Tuesdays and Thursdays, 10:30-11:55, 269 Lauritsen.
Any changes will be announced well in advance.

Textbook for Phys 12b:

Liboff, Introductory Quantum Mechanics, 3rd ed;
Recommended: Griffiths, French & Taylor, Eisberg & Resnick, Feynman, ...
There are many good books on QM, in the Bookstore and libraries.

Class notes:

PDF files below under "Handouts"

Recitations:

Wednesday, 3-4 PM, Location: 107 DWN
Prabha Mandayam: prabhamd AT its.caltech.edu; Office hours: Monday, 2:00-3:00pm, 449 LAU
Wednesday, 8-9 PM, Location: 269 LAU
Heywood Tam: tam AT caltech.edu; Office hours: Wednesday, 2:00-3:00pm, 335 LAU

Graders:

Miguel Bandres, bandres AT caltech.edu: problem sets 1-4;
Nate Bode, nbode AT caltech.edu: problem sets 5-8.
Please email requests for extensions to the appropriate grader, before the assignment is due.
Meetings with the graders to discuss questions about grading should also be arranged via email.
Or simply email the corresponding grader about your question and drop your PS in their mail box at Bridge adding a note about your concern.
Midterm and final exams to be graded by TA's and graders. See prof for extensions.

Problem Sets:

Handed out on Thursday of each non-exam week, due in the Physics 12b IN box in 264 Lauritsen by 5pm on the following Thursday, returned to the Physics 12b OUT box in 264 Lauritsen by the following Monday morning. Solution sets will be posted on the web. You are strongly encouraged to check your work when it is returned to you. Problem sets are essential for mastering the material in this class!

Exams:

Midterm and final exams during appropriate weeks of the term (5th and 10th). Both will be take-home and ``limited" open-book (only the text and class notes allowed). The final exam will be comprehensive.

Grading:

Approximately 50% problem sets, 15% midterm, 35% final exam.

Extensions:

• OFFICIAL policy: Work (the entire problem set) will be accepted up to one week late at 1/2 credit, no credit thereafter. Please put a note at the top of your problem set if it is late.
• Students may request extensions from the corresponding grader (see emails above). Extension requests are governed by the honor system.
• One extension (for up to one week) is allowed without question (your silver bullet). Please put a note at the top of your problem set that you are using your silver bullet.
• Extension requests should be accompanied by a GOOD excuse (eg, physical or mental illness), and in principle should be accompanied by a letter from a doctor or the dean.
• Please put late or extension problem sets in the corresponding grader's mail box in Bridge.
• Late papers make far more work for the graders, who have their own set of pressures and deadlines as graduate students. There is no entitlement to extensions, so please do not be demanding.

Honor Code:

Work is governed by the honor system. You may not use sources that contain the answer to a problem or to a very similar problem. Discussion with others is encouraged, but the work you hand in must be your own. In particular, do not use solution sets from previous years, or problem/solution books!

Feedback:

I greatly appreciate student feedback; feedback prior to the end-of-term evaluations lets me modify the class to fit your needs. In person, by email to ajw AT caltech.edu, by campus mail, whatever you like. If you would like to preserve your anonymity, campus mail will usually work. My mailbox is next to 256 Lauritsen. Or, talk to your:

Ombudsfolk:

Ombudsfolk are student volunteers who represent the students of each of the undergrad houses. They collect suggestions, comments, complaints, etc, and present them to the head ombudsperson at periodic meetings (free lunch!). Talk to your ombudsperson!
Ombudsfolk, please send me your info!
Liuyi Pei, liuyi AT caltech.edu, Page
Joel Nikolaus, joel AT caltech.edu, Blacker
Xueliang (Leon) Liu, xueliang AT caltech.edu, Avery
Aliza Malz, aliza.malz AT gmail.com, Dabney
Eugeniu Plamadeala, eugeniu AT caltech.edu, Ruddock

Brief Outline of course, winter term:

• Classic Experiments, Old Quantum Theory (Liboff Chaps 1 & 2)
• The wave function, Schrodinger Eqn, uncertainty (Liboff Chaps 3 & 4)
• States, Observables, Operators, Dirac Notation (Liboff 4.4 -- 4.6, 5.5, 7.4)
• Eigenvalue problem, eigenspectrum, Hilbert space bases (Liboff Chap 4)
• Postulates of QM (Liboff Chap 3)
• Solutions to the time independent Schrodinger Eqn in 1 dimension
• Infinite and finite square well (Liboff 4.1, 8.1)
• Quantum Harmonic Oscillator (Liboff 7.2 - 7.4)
• Reflection and Transmission, tunneling, in 1 dimension (Liboff 7.5 - 7.7)
• Two-state systems (the qubit)
• Schrodinger Eqn in 3D, central forces, Hydrogen (Liboff Chap 10)
• Angular Momentum and Spin (Liboff Chap 9)
• Atoms, solids, radiation...

Handouts: (Access to solutions are restricted to Caltech)

• Quantum Mechanics Timeline (CPEP)
• QM units (gif)
• Physical constants from PDG (pdf)
• Quantum Phenomena simulations from Physics Educational Technology
• Phys 12b Assignment 1 (pdf), due in Ph12 box in 264 Lauritsen by 5pm Thursday, 1/17/08.
• Phys 12b Assignment 1 Solutions (pdf).
• Phys 12b lectures, week 1 (pdf, 1 MB)
• Phys 12b Assignment 2 (pdf), due in Ph12 box in 264 Lauritsen by 5pm Thursday, 1/24/08.
• Phys 12b Assignment 2 Solutions (pdf).
• Phys 12b lectures, week 2 (pdf, 1 MB)
• Phys 12b Assignment 3 (pdf), due in Ph12 box in 264 Lauritsen by 5pm Thursday, 1/31/08.
• Phys 12b Assignment 3 Solutions (pdf).
• Phys 12b lectures, week 3 (pdf, 1 MB)
• Phys 12b Assignment 4 (pdf), due in Ph12 box in 264 Lauritsen by 5pm Thursday, 2/7/08.
• Phys 12b Assignment 4 Solutions (pdf).
• Phys 12b lectures, week 4 (pdf, 1 MB)
• Phys 12b Demo Day notes (pdf)
• Phys 12b midterm (pdf), due in Ph12 box in 264 Lauritsen by 5pm Thursday, 2/14/08.
• Phys 12b Midterm solutions (pdf)
• Phys 12b Mid-term grade distributions (pdf)
• Phys 12b lectures, week 5 (pdf, 1 MB)
• Phys 12b Assignment 5 (pdf), due in Ph12 box in 264 Lauritsen by 5pm Thursday, 2/21/08.
• Phys 12b Assignment 5 Solutions (pdf).
• Phys 12b lectures, week 6 (pdf, 1 MB)
• Phys 12b Assignment 6 (pdf), due in Ph12 box in 264 Lauritsen by 5pm Thursday, 2/28/08.
• Phys 12b Assignment 6 Solutions (pdf).
• Phys 12b lectures, week 7 (pdf, 1 MB)
• Phys 12b Assignment 7 (pdf), due in Ph12 box in 264 Lauritsen by 5pm Thursday, 3/6/08.
• Phys 12b Assignment 7 Solutions (pdf).
• Phys 12b lectures, week 8 (pdf, 1 MB)
• Some notes on Wavefunction collapse, quantum reality, and all that (pdf)
• The delayed choice quantum eraser, Wikipedia article, experimental paper.
• Phys 12b Assignment 8 (pdf), due in Ph12 box in 264 Lauritsen by 5pm Thursday, 3/13/08.
• Phys 12b Assignment 8 Solutions (pdf).
• Phys 12b lectures, week 9 (pdf, 1 MB)
• Plots of 1-dimensional scattering (pdf, 1 MB)
• Phys 12b lectures, week 10 (pdf, 1 MB)
• Phys 12b final (pdf).
• Phys 12b final Solutions (pdf).
• Phys 12b FINAL grade distributions (pdf)
• Phys 12b lectures, on 3D central forces, Hydrogen (Not covered in Phy12b; you will do this in Ph125!) (pdf, 0.5 MB), and plots of 3D wavefunctions (pdf, 0.5 MB).