# Quantum Mechanics and Path Integrals: Emended Edition

*This World Wide Web page written by
Dan Styer,
Oberlin College Physics Department;*

http://www.oberlin.edu/physics/dstyer/FeynmanHibbs/;

last updated 15 June 2012.

I can well remember the day thirty years ago when I
opened the pages of Feynman-Hibbs,
and for the first time saw quantum mechanics as a living piece
of nature rather than as a flood of arcane algorithms
that, while lovely and mysterious and satisfying,
ultimately defy understanding or intuition.
It is my hope and my belief that this emended edition will
open similar doors
for generations to come.

The book *Quantum Mechanics and Path Integrals*
was first published in 1965, yet is still exciting, fresh,
immediate, and important.
It combines qualitative insight and technical brilliance
in Feynman's characteristic manner.
Although several more recent books treat this topic,
these books emphasize the *mathematics* of path
integration rather than the *physics* of quantum mechanics.
All of these books lack Feynman's insight and verve.
Indeed, the first sentence of Larry Schulman's book
*Techniques and Applications of Path Integration* is
"The best place to find out about path integrals is
in Feynman's paper."

The first edition of this book suffered from a grave flaw:
It was riddled with typographic errors and infelicities.
I described the book as "full of extraordinary insight and excruciating errors"
and produced a list of 879 errors
that extended to 39 pages.

### Uses

This book was written by Feynman and his graduate student Hibbs
as a textbook -- it has problems to assign, for example -- but
it was written as a textbook in Feynman's iconoclastic style.
The book is bursting with insight, most of which will be lost on a
first-time reader. Its main role, in my opinion, is to open up the
minds of teachers and researchers and students.
In that role the emended editions makes a great supplement
in undergraduate and graduate level quantum mechanics courses.
### Story of the Book

The story of the book's genesis is given on page 399 of Jagdish
Mehra, *The Beat of a Different Drum: The Life and Science
of Richard Feynman* (Clarendon Press, Oxford, 1994).
Anyone who has battled through he many errors and infelicities
of the 1965 edition will agree with Hibbs that "neither of us
was dedicated to getting the thing out".
### Errors in the Emended Edition

I'm upset but not surprised to find that even the emended edition contains
errors.
### Difficult Points

Here are explications of several difficult points:

Here is a spreadsheet to calculate and plot
the sharp-edged slit diffraction results of figure 3-6.
To use it you will need Microsoft Excel and the
XNUMBERS
free open-source add-in package.