To most readers the name Edward Teller will produce the immediate response
‘Father of the H-Bomb’ – full stop. But a few might recall a book called
The Structure of Matter co-authored by Teller and published in 1961. This
introduced atomic, molecular and solid state physics clearly, readably and
with a minimum of mathematics. Conversations on the Dark Secrets of Physics
is in the same vein.

I found the title misleading. One expects another visit to the flying
circus of modern physics complete with the usual acts: Erwin Schrodinger
and his wonderful cat, Einstein, Rosen and Podolsky and their juggling spins,
the fearless quark hunters and so on. Teller mentions some of these but
his purpose is different.

A better title might have been The Golden Road of Physics. Starting
with Pythagoras and the ancient Greeks, the authors discuss the nature of
space, introduce Einstein and relativity, while statics and dynamics lead
to Galileo Galilkei, Johan Kepler, and Isaac Newton’s classical mechanics.
A chapter on statistical mechanics is followed by an introduction to electricity
and magnetism. Evidence for the existence and size of atoms leads to Niels
Bohr, Louis de Broglie and quantum physics. A final chapter discusses applications
of quantum theory, solid state physics, superconductivity and lasers.

Such a contents list sounds heavy for a book of 247 pages. But the general
approach is light and accessible. The atmosphere of the book is of a kindly
old Central European uncle explaining physics to a young nephew and niece.
The co-authors raise queries and comments in footnotes. Edward Teller answers,
cracks a joke or turns the question around. Mathematics is kept to a minimum.
Each chapter starts at a low level of understanding, but often ends up at
a dramatically high one. Questions at the end of each chapter have answers
that are both expansive and illuminating.

I enjoyed the early chapters the most, especially those on statistical
mechanics and atoms. The chapters on quantum theory seem weaker, perhaps
because there have been so many other good treatments of the subject.

Compared with today’s lavishly illustrated, multicoloured textbooks,
Conversations seems a bit oldfashioned. This impression is reinforced by
the use of outdated ‘cgs’ units. But the general tone – of a conversation
with someone who loves physics and is healthily sceptical about physicists
as human beings not to mention a physicist’s common prejudices about mathematicians
and chemists – makes the book more than a mere text.

Teller’s approach to a subject is interesting. He makes a statement,
follows through its consequences and only then provides an explanation and
justification of his original postulate. For example, on statistical mechanics,
he starts from ‘a simple basic law . . . energies add and probabilities
multiply’. What this means and why it should be so is left until much later
in the chapter. The atmosphere is individual: the personal approach to the
universe of a particular physicist. In this sense it makes a fascinating
contrast to, for example, Richard Feynman’s Nature of a Physical Law.

At what sort of reader is the book aimed? The authors hope that it will
enable ‘otherwise educated adults to catch up on the new physics’. Well,
possibly; but a good background of school maths would be almost essential
to get through most chapters. The book would suit someone who struggled
through A Brief History of Time and feels hungry for a solid basis of physics
on which to rest their ideas. It would be an excellent present for the 15
or 16-year old student enthused by physics, but wanting something less arid
than a textbook. And for the people they often grow up into – professional
physicists who want to remind themselves of their sense of wonder at the
broad sweep of physics.

Geoff Jones is the sub dean of the School of Mathematical and Physical
Sciences at the University of Sussex. He is a physicist with a particular
interest in quantum optics and the teaching of quantum physics.

SEVERAL years ago, Brandt and Dahmen produced The Picture Book of Quantum
Mechanics (Wiley, 1985), which illustrates the behaviour of quantum mechanical
wave functions for scattering, particles trapped in a potential well, and
so on. This invaluable aid for students used illustrations generated by
a mainframe computer. With the advance in PC technology since the mid-1980s,
the authors have been tempted into shoehorning the program into a version
that will run on the IBM PC and PS/2 or compatibles, offering the prospect
that every student can generate examples of solutions to Schrodinger’s equations
and watch them develop on the screen. This is an excellent idea, but it
falls down considerably in the execution.

The concept is good, and the team deserves at least two cheers for the
effort they have made. Unfortunately, even the cut down version of the program
still requires pretty heavy computer power – at least 640K of memory plus
a maths coprocessor (the book, incidentally, says only that the coprocessor
is ‘recommended’; but the introductory ‘README’ file says it is mandatory,
and indeed we could not run the main program without the coprocessor).

A typical undergraduate might have difficulty running the pack age.
It is relatively easy to get the introduction up, but the main package is
not user friendly, and some knowledge of software engineering is essential
to get the full benefit.

We used a Tandon 386/20 to run the program. The demonstrations will
run in three modes. An automatic mode simply runs through the ready-made
demonstrations of examples, such as free particle motion in one dimension
(too simple to be very interesting or informative), potential wells and
scattering in three dimensions (interesting and informative), while a full
manual mode allows the user in principle to set up new problems, specifying
all kinds of parameters. In fact, we found this task much too hairy to contemplate,
and our assessment of the package is based on using the third semi-automatic
mode, in which each demo is displayed separately and retained for study
as long as the user wants.

In general, the displays are very good. There is a problem, though,
with the presentation, in that final states are plotted on the screen first,
with preceding states then filled in backwards in a simulated three-dimensional
display, ending up with the initial state of the problem at the ‘back’ of
the screen. Confusing! It also takes a long time for some of these pictures
to build up. Although the two-dimensional graphs are plotted in five seconds
or less, the three-dimensional displays take 30 seconds or more per plot.

Another problem, especially with the demonstrations of three-dimensional
bound states, is that the excellent graphics are followed by good descriptive
text, but it is impossible to flip back to the picture after reading the
text. There seems to be an implicit assumption that each user has a high-quality
printer available to take immediate hard copies of the diagrams. The final
subsection, presenting functions of mathematical physics in visual form,
is particularly useful.

On the programming side, the package is not very well thought out. For
example, the cursor prompt within the program is the same as the MSDOS prompt,
and when exiting from the semi-automatic mode you are returned to the system,
not the parent program of the package. This left us at first puzzled at
the lack of response of the program to further commands.

Also, there is no way to jump about within the program to a particular
example – you can choose a specific chapter of the book, but then have to
wade through this in sequence to get the example you want.

The main point for the package is that it does give an excellent picture
of what is going on in examples, such as the penetration of a barrier by
a particle.

It is a useful package for teachers of quantum mechanics, for setting
up demonstrations and as an aid in the production of worked examples or
exam questions. But it is not cheap enough or friendly enough for use by
undergraduates.

Geoff Jones lectures in physics at the University of Sussesx.

John Gribbin is physics consultant to New ÐÓ°ÉÔ­´´.