Quantum Physics

Winter 2010

Go to **home page for
Ph12c**

**Course description: **An
introductory course in quantum mechanics.

**Class meetings**:
Tuesday and Thursday 10:30-11:55 am in **269
Lauritsen**, starting January 5, 2010.

**Feedback:** If you want to send a
comment about the course, click here.

**Instructor: **John Preskill, 206
Annenberg, X-6691, preskill@caltech.edu.

Recitation leaders:

Milivoje
Lukic, mlukic@caltech.edu

Heywood
Tam, tam@caltech.edu

**Recitation sessions:**

Recitation leaders: Tuesday 8:00-9:00pm, 269 Lauritsen, Milivoje Lukic

Wednesday 7:30-8:30pm, 269 Lauritsen, Heywood
Tam

**Graders:
**Miguel Bandres, bandres@caltech.edu

Chaitanya Rastogi, rastogi@caltech.edu

**Textbook:** *Introductory
Quantum Mechanics (4 ^{th} edition) by
Richard L. Liboff*

We will cover most of the first 8 chapters of Liboff, plus some supplementary material.

**Grading:** Grades will be based
on weekly problem sets (30%), a midterm (30%), and a final exam (40%).

**Homework: **Problem sets will be
posted on this page on Thursday, and will be due in the **Physics 12b IN****-box** in 264 Lauritsen
at 5:00 pm the following Thursday. Graded homework will be returned to the **Physics
12b OUT****-box** in 264 Lauritsen by the following Monday morning. Solution sets
will be posted on this page. Unexcused late homework will be accepted for half
credit up until one week after the due date; there is no credit if your
assignment is more than one week late. If your homework will be late for a good
reason, you may request an extension before the assignment is due by sending
email to that week’s grader.

**Honor Code: **Discussion with
others is encouraged, but the work you hand in must be your own. In particular,
do not use homework solutions from previous years or exams and exam solutions
from previous years.

**Lectures** (tentative schedule)**:**

Jan 5. Quantum
interference

Jan 7. Hamiltonian
mechanics

Jan 12. Quantum postulates I: states and observables

Jan 14. Quantum postulates II: measurement

Jan 19. Quantum postulates III: evolution (lecture notes)

Jan 21. The density operator (lecture
notes)

Jan 26. Decoherence (lecture
notes)

Jan 28. What is measurement? (lecture notes)

Feb 2. Particle in a box

Feb 4. Uncertainty principle (lecture
notes)

Feb 9. Free particle (lecture
notes)

Feb 11. Bound states in one dimension

Feb 16. Harmonic oscillator I: creation and annihilation operators

Feb 18. Harmonic oscillator II: coherent states (lecture
notes)

Feb 23. Scattering I: the potential step

Feb 25. Scattering II: the rectangular potential
barrier

Mar 2. The WKB approximation (lecture
notes)

Mar 4. The finite potential well (lecture
notes)

Mar 9. The periodic potential (lecture
notes)

Mar 11. Entanglement and the

**Homework assignments:**

Read Liboff, Chapters 1 and 2.

Problem
Set 1, due Jan 14: Uncertainty, Hamiltonian dynamics, and quantum
interference. Solutions. Graded
by Miguel.

Read Liboff, Chapters 3 and 4.

Problem
Set 2, due Jan 21: Eigenstates and eigenvalues. Solutions. Graded
by Chaitanya.

Problem
Set 3, due Jan 28: Some novel measurements. Solutions. Graded
by Miguel.

Problem
Set 4, due Feb 4: Density operator and decoherence.
Solutions. Graded
by Chaitanya.

Read Liboff, Chapters 5 and 6.

Problem
Set 5, due Feb 18: Uncertainty. Solutions. Graded
by Miguel.

Read Liboff, Chapter 7 through Section 7.4.

Problem Set 6, due
Feb 25: Harmonic oscillator. Solutions. Graded
by Chaitanya.

Read Liboff, Chapter 7, Sections 7.5 through 7.9.

Problem Set 7, due
Mar 4: Damped oscillator and scattering. Solutions. Graded
by Miguel.

Read Liboff, Chapter 7, Sections 7.10, 7.11, Chapter
8, Sections 8.1-8.4

Problem
Set 8, due Mar 11: Bound states. Solutions. Graded by Chaitanya.

**Exams:**

Midterm
exam, available Feb. 4 and due Feb 10. Covers all
material through Problem Set 4. Solutions.

Sixty exams were received. The median was 87 and the mean was 84. Eleven
students scored 100.

Final: available Mar 11 and due Mar 17. Covers everything in the course, emphasizing material from after
the midterm.

Cover
page with final exam instructions. (You may open this now.)

Final exam. (Open only when you
are ready to take the exam.). Solutions.

Fifty-six exams were received. The median was 74 and the mean was 67. Eleven
students scored 90 or higher.

**Grades:**

Final grades were determined using the formula Grade = 0.3(Homework) +
0.3(Midterm) + 04(Final).

The median final grade was 79 and the mean was 77.

The ranges for letter grades were:

A+ 96-100

A 89-95

A- 80-88

B+ 75-79

B 65-74

B- 59-64

C+ 50-58

There were 5 A+’s, 14 A’s, 13 A-’s,
5 B+’s, 10 B’s, 7 B-’s, 2 C+’s (Total=56).

The mean GPA was 3.49.