Physics H190

Black Body Radiation and the

Origin of Quantum Mechanics:

What Did Planck Do?


Spring, 2005

University of California, Berkeley

Instructor:  Robert Littlejohn
Office:  449 Birge
Office Hours:   Tu 4-5
Telephone:  642-1229
Email:  h190@wigner.berkeley.edu

Lecture:  9 Evans
Time:  W 4-6

Course Description

In this course we will take a particular moment in the history of physics---Planck's derivation of his formula for the spectrum
of black body radiation, which was the first time that Planck's constant h entered physics---and use it to extract lessons
important for a modern student of physics.  We shall learn some history in the process, but we will not spend time on physical
theories (such as the ether) that are no longer relevant to physics.  We shall cover enough classical thermodynamics to
appreciate the problems that Planck and others were struggling with in trying to combine thermodynamics and electromagnetic
theory, and we shall come to understand the role these played in the development of statistical mechanics.   In the process we
shall cover some of the issues in the foundations of statistical mechanics, some of which are still not completely understood.

An initial list of topics includes the following:  The Clausius-Helmholtz-Kelvin formulation of classical thermodynamics.  Kirkhoff's
laws.  Boltzmann's derivation of the Stefan-Boltzmann law.  Wien's displacement law.  The Maxwell-Boltzmann distribution,
kinetic theory, and Boltzmann's probabilistic conception of entropy.  The Rayleigh-Jeans law.  Boltzmann's H-theorem.  Planck's
derivation of the formula for the black body spectrum.  The Gibbs-Einstein formulation of classical statistical mechanics.  The
equipartition theorem.

Many of these are standard topics in Physics 112, but they are usually covered rather superficially, and we shall go into them
in more depth.  We shall also pay more attention to the fundamental physical principles involved than is usually done in our
upper division courses.   If interesting issues from other fields of physics arise in the process of studying these questions---for
example, the electromagnetic stress tensor or the equations of fluid mechanics---we may make digressions into these topics,
at a level appropriate for advanced undergraduates.

If there is still time left after we cover these topics, we may either continue with the story of the evolution of quantum mechanics,
or complete the theory of black body radiation and related topics from a modern (field theoretic) standpoint.

Textbooks

There will be no official textbook for the course, but reading assignments will be posted on this web site.  The following is a list
of references for the beginning of the course:

S. Brush, The Kind of Motion We Call Heat.
E. Fermi, Thermodynamics (Dover, 1956).
Garber and Brush, Maxwell on Heat and Statistical Mechanics.
M. Jammer, The Conceptual Development of Quantum Mechanics (McGraw-Hill, 1966).
H. Kangro, Early History of Planck's Radiation Law (Taylor and Francis, 1976).
T. Kuhn, Black-Body Theory and the Quantum Discontinuity, 1894-1912 (University of Chicago, 1978).
M. Planck, The Theory of Heat Radiation  (Dover, 1991).
Richtmyer, Kennard and Lauritsen, Introduction to Modern Physics (McGraw-Hill, 1955).\
E. T. Whittaker, History of Theories of Aether and Electricity (1951).

Other references will be added as we proceed.

Organization

The class will be organized much like a regular lecture course, except that we will cover 1/2 as much material
(since the course has only 2 units).

Prerequisites

The prerequisites for the course are honors standing, Physics 137A, and Physics 112 (which may be taken
concurrently).    Honors standing means a 3.3 average in upper division Physics  courses.  You do not have
to be working on or planning an honors project (which is needed however  to graduate with honors.)

Grade, Exams

The grade will be based on weekly homework.  There will be no final exam.

Homework Policy

Homework will be posted on this web site normally by Wednesday of each week.    Homeworks will be due
in class, Wednesday at 4pm.   I will give approximately half as much homework as I would give in a regular
lecture class.  Late homeworks will be accepted at 1/2 credit (up to one week late).  Homework more than
one week late will not be accepted.  Exception:  Each student is allowed one free late homework
per semester (up to one week late), no questions asked.

Notes


Selections for Reading (in pdf format)

Homework Assignments

Lecture Notes are Professor Littlejohn's hand-written notes for lectures.  The lecture notes posted here will usually be like the actual
lectures, but no guarantees are made.