Richard Feynman must rank as one of the great teachers of physics of the 20th century. Like Michael Faraday a century earlier, Feynman combined brilliant research at the forefront of knowledge with the communication skills that can come only from having thought out the fundamentals of the subject for yourself. His great undergraduate lectures in physics, first printed in 1965, were from the outset to be transcribed and edited, though preparing them for publication turned out to be a lot of work. Thirty years later the same treatment was given to some of Feynman's other courses, and his lectures on gravitation and on computation were published in 1995 and 1996, now available in paperback.
The lectures on gravitation were delivered in 1962-63. They were aimed at advanced graduate students and postdoctoral fellows who were familiar with the methods of relativistic quantum field theory - in particular with Feynman-diagram perturbation theory in quantum electrodynamics.
Feynman introduces the subject by asking you to imagine that instead of meeting gravity as the first of the forces to be described mathematically (with quantum and particle physics coming centuries later) as is the case on Earth, you come from some small region of the universe where scientists know all about the other 30 fields of the universe and about nucleons, mesons etc, but not about gravitation. Suddenly in this physics community, which for the sake of discussion he locates on the planet Venus, an amazing new experiment is performed, which shows that two large neutral masses attract each other with a very, very tiny force. How would the Venusians try to interpret this new experimental fact in terms of the field theories with which they are already familiar? And so the lectures proceed.
The lectures on computation are more recent, given in 1983-85 as "Potentialities and Limitations of Computing Machines". Although the lectures changed from year to year, often due to contributions from guest lecturers, the basic structure remained the same: an introductory section on computers, followed by five sections exploring the limitations of computers arising from the structure of logic gates, mathematical logic, the unreliability of components, the thermodynamics of computing and the physics of semiconductor technology. In a sixth section, Feynman discussed the limitations of computers due to quantum mechanics, thus anticipating the explosion in quantum computation that we are now seeing. Once again, the task of reducing the lectures to book form has been a formidable one, superbly executed by Anthony Hey and Robin Allen.
The forewords to both sets of lectures give carefully worded evaluations of which parts of each book are timeless, and which are now of primarily historical interest. The ratios are very different in the two cases. Much of the lectures on gravitation might be somewhat dated for today's graduate student. With the lectures on computation, the editors have relegated the part on hardware, together with some personal reminiscences, to the end, almost as appendices. But overall, Lectures on Computation is a classic: I can think of no finer introduction to the underlying concepts for anyone who will ever use a computer. Those who have enjoyed reading it include both my 12-year-old nephew and the head of the Quantum Structures Research Initiative at Hewlett-Packard Laboratories.
Andrew Briggs is professor of materials, University of Oxford.
Feynman Lectures on Computation
Author - Richard P. Feynman
Editor - Anthony J. G. Hey and Robin W. Allen
ISBN - 0 14 028451 6
Publisher - Penguin
Price - £18.99
Pages - 303