Bookshelf

1 April 2001

Selected Papers of Richard Feynman

(with commentary), edited by Laurie
M Brown, World Scientific Series in 20th Century Physics, Vol. 27, ISBN 981 02 4130 5
hbk ISBN 981 02 4131 3 pbk.

After A Quantum Legacy, the selected papers of Julian Schwinger (edited by
Milton; see December
2000 Bookshelf
), it is fitting that the next volume in this carefully selected series
covers the work of Richard Feynman.

Now a cult figure, Feynman is fast
becoming one of the most prolifically documented physicists of the past century. As well
as his own popular work (You Must Be Joking, What Do You Care What Other
People Think?
) and his various lectures, there are biographies or biographical
material by Gleick, Brown and Rigden, Mehra, Schweber, Sykes, and Gribbin and
Gribbin.

Anecdotes about such a flamboyant character are easy to find, but the
man’s reputation ultimately rests on his major contributions to science, which this book
amply documents. Chapters, of various lengths, deal with his work in quantum chemistry,
classical and quantum electrodynamics, path integrals and operator calculus, liquid
helium, the physics of elementary particles, quantum gravity and computer theory. Each
has its own commentary.

As a foretaste of things to come, the first chapter serves
up just a single paper – “Forces in molecules” – written by Feynman at the age of 21, in
his final year as an undergraduate at MIT. This result – the Hellmann-Feynman theorem –
has played an important role in theoretical chemistry and condensed matter
physics.

Chapter 2 begins with Feynman’s 1965 Nobel Lecture, goes on to include
work with John Wheeler at Princeton, which explored the underlying assumptions about
the interaction of radiation and matter, and concludes with the classic 1949 papers that
presented his revolutionary approach to quantum electrodynamics.

The Nobel
Lecture alone is worth reading – clearly a major early source of Feynman anecdote, such
as the Slotnick episode. One is struck by Feynman’s ambivalent attitudes – his enormous
regard for father figures such as Wheeler and Bethe on the one hand, and his clear
disdain for many contemporaries on the other. Another good read in this chapter is
Feynman’s paper presented at the 1961 Solvay meeting, and the ensuing
discussion.

Chapter 3 deals with the detailed presentation of the path integral
approach, which enabled Feynman to dissect electrodynamics and look at it from a fresh,
uncluttered viewpoint.

From 1953 to 1958, Feynman looked for fresh pasture and
produced a series of seminal papers on the atomic theory of superfluid helium, which is
presented in Chapter 4.

Chapter 5 is split into two parts. The first, on weak
interactions, includes the classic 1957 paper with Gell-Mann and some lecture notes from
the 1960s exploring the consequences of SU3 symmetry for weak interactions. The
second part – by far the largest section of the book – deals with his approach to partons,
quarks and gluons. Feyman began thinking about describing hadrons simply as an
assembly of smaller parts – his partons – just when experiments were beginning to probe
this inner structure. This is a good example of how Feynman, arriving at a fresh interest,
would invariably strip problems down to their essential parts before reassembling them in
a way that he, and many other people too, understood better.

Feynman’s interest in
numerical computation went back to his time at Los Alamos, when he had to model the
behaviour of explosions using only the mechanical calculators of the time. Coming back
to the subject in the 1980s, he went on to pioneer the idea of quantum computers. Apart
from the prophetic papers published here, this aspect of his work has been well
documented in The Feynman Lectures on Computing (ed. A J G Hey and R W
Allen, Perseus).

Selected Papers of Richard Feynman concludes with a full
bibliography. Even without the burgeoning Feynman cult, such a selection of key papers
is a useful reference. However, with almost 1000 pages, the book could perhaps have
been better signposted. The selected papers are not listed in the initial contents and the
pages have no running heads to indicate how the chapters fall.

Gordon Fraser,
CERN.

Calorimetry: Energy Measurement in Particle Physics

by Richard Wigmans,
Oxford University Press, ISBN 019 850296 6, 726pp, £85.

The role of calorimetry
in high-energy physics has become increasingly important during the last 20 years. This
is due to the increase in energy of the particle beams available at the major accelerators
and to the need for hermetic detectors. The 1980s, in particular the second half of the
decade, saw an important breakthrough in the understanding of the mechanisms

The theme
around which this breakthrough took place is “compensation”: for a compensating
calorimeter e/h = 1, where e represents the response to an electromagnetic and h
the response to a non-electromagnetic,that is purely hadronic, shower of the same
energy. For compensating calorimeters the energy measurement of electrons and hadrons
of the same energy yields the same average response for all energies, at the same time
leading to optimal hadronic energy resolution. It is also a prerequisite for linearity of the

In practice, very few compensating calorimeters
have been built for major experiments (one example is the calorimeter of the ZEUS
experiment at HERA, discussed in the book), probably because, in practice, achieving
compensation means making a concession to the electromagnetic energy resolution.
None of the experiments planned at the Large Hadron Collider, for example, will employ
a compensating calorimeter. The importance of the research into compensation is
nevertheless very large in that it led to a much better understanding of calorimetry in
general. The author of the book has made original and essential contributions to this field
through his own research.

The book reflects the deep and encyclopedic knowledge
that the author has of the subject. This makes the book a rich source of information that
will be useful for those designing calorimeters and for those analysing calorimeter data,
for a long time to come. At the same time the book is not always successful in finding a
way of organizing and conveying all of this knowledge in a clearly structured and
efficient way. Parts of the book are rather narrative and long-winded.

The most
important chapters are those on Shower Development, Energy Response, Fluctuations
and Calibration. Also, that on Instrumental Aspects contains essential information. The
chapters on generic studies and on existing (or meanwhile dismantled) and planned
calorimeter systems, are interesting but less necessary parts of a textbook. Moreover, the
author does not always keep to the subject – calorimetry – leading to unnecessary
excursions and, what is worse, outdated material. It would, on the other hand, be
interesting if the author, in his description of the calorimeters under construction for the
Atlas experiment, had been a bit more explicit on what, in the light of the ideas developed
earlier in the book, the optimal approach would be to (inter)calibrating this very complex
calorimeter system.The chapter on Calibration is probably the most essential part of the
book, bringing together many of the fundamental issues on shower development, signal
generation and detection. Reading this chapter, one gets the impression that in fact it is
impossible to calibrate calorimeters, but the style chosen by the author is only to
emphasize that the issue is subtle and great care must be taken. The chapter contains
information that is extremely worthy of consideration, culminating in the recommendation
that, in the case of non-compensating calorimeters, individual (longitudinal) calorimeter
sections should be calibrated by the same particles generating fully contained showers in
each section, a recommendation that, in practice, cannot always be satisfied. In his ardour
to emphasize the importance of the (inter)calibration of longitudinal calorimeter segments,
the author even invokes decays, such as that of the neutral rho into two neutral pions,
that do not exist in nature – we get the point and forgive him. It is, however, true that
there are more places where the book would have profited from a critical, final
edit.

Calorimetry is a book that describes the essential physics of
calorimetry. It also contains a wealth of information and practical advice. It is written by
a leading expert in the field. The fact that the discussions sometimes do not follow the
shortest path to the conclusion and that perhaps the “textbook part” of this work should
have been accommodated in a separate volume does not make the book less important: it
will be amply used by those trying to familiarize themselves with calorimetry and in
particular by those analysing the data of the very complex calorimeter systems of future
experiments, such as at LHC.

Jos Engelen,NIKHEF, University of
Amsterdam.

Quarks and Gluons: a Century of Particle Charges

by M Y Han (Duke),
World Scientific Publishing, 168pp, ISBN 981 02 3704 9 hbk $34/£21, ISBN 981 02 3745 6 pbk)$16/£10.

This is a readable little book on particle physics and is aimed
at those with no previous exposure to the subject. It starts with the discovery of the
electron in 1897 and works its way more or less historically up to the present. That
means, of course, that it contains a lot about leptons and photons as well as the quarks
and gluons of the title.

The guiding theme is the discovery of different kinds of
conserved charges – first electric charge, then baryon number and the lepton numbers,
and finally the more subtle kind of charges that are the source of the colour force
between the quarks.

Like Stephen Hawking, the author manages to avoid all
equations, except E = mc2. The style is chatty and colloquial (American), which
will have some non-native English readers running for their phrase books. For example,
correct predictions are “right on the money”, and when the terminology seems comical
the reader is exhorted to “get a grip on yourself”. Nevertheless, as one would expect from
a leading contributor to the field, Han takes care to get things right even when using
simple language, as for example in his discussion of spin.

The jacket says that the
book will be “both accessible to the layperson and of value to the expert”. I imagine that
the latter refers to its value in helping us to communicate with non-experts.

I have
those charges that are (within current limits) absolutely conserved leaves the reader with
the impression that nothing much is understood about the weak interaction. The author
even says that the weak charges have yet to be identified. All of the beautiful
developments of electroweak unification are omitted. Also, there is no mention of the
exciting possibilities that lie in the near future. This makes the subject seem a bit
moribund and musty. For example, we are told that the discovery of the pion in 1947
was “one of the last hurrahs” of cosmic-ray physics, whereas in fact that field continues
to show astonishing vitality, with neutrino studies, ultrahigh-energy primaries and other
fascinating phenomena promising a rich future.

Bryan Webber, Cambridge.

Anomalies in Quantum Field Theory

by R A Bertlmann, Oxford University
Press, ISBN 01 850762 3, pbk £29.95.

Field theory “anomalies” constitute a
long-standing source of physics and mathematics. They have remained fascinating for
physicists and mathematicians, as ongoing developments in string and brane theory
show.

This book gives a comprehensive description of the many facets of this
subject that were known before the mid-1980s. It is essentially self-contained and thus
deserves to be called a textbook. Both mathematicians and physicists can learn from this
volume.

With a modest knowledge of quantum mechanics, a mathematician can
read about the history of the subject: the puzzle of the decay of the neutral pion into two
gamma-ray photons; the inconsistencies of the perturbative treatment of gauge theories
related to the occurrence of anomalies; the original Feynman graph calculations; and the
theoretical constructions that introduced relationships with topology, up to the elementary
versions of the index theorem for families.

The physicist will find all of the
necessary equipment in elementary topology and differential geometry combined in
constructions that are familiar to professional mathematicians. S/he will find thorough
descriptions of the algebraic aspects that emerged from perturbation theory, both in the
case of gauge theories and in the case of gravity, and an introduction to the way in which
they tie up with index theory for elliptic operators and families thereof.

The book
reads fluently and is written so clearly that one not only gets an overview of the subject,
but also can learn it at an elementary level.

The bibliography is a rather faithful
reflection of the physics literature and includes a few basic mathematical references,
chooses.

As mentioned, the subject is still developing in the direction of new
mathematics and, possibly, new physics in the context of strings and branes. One may
therefore regret that the book stops around the developments that took place in the
mid-1980s.

The book is already more than 500 pages. Since it is essentially
self-contained and every topic that is dealt with is described in sufficient detail to allow a
non-specialist to get acquainted with it, at least at an elementary level, the mathematical
techniques do not go beyond elements of differential geometry, as well as of homology,
cohomology and homotopy theory. Generalized cohomology theories, including
K-theory, only appear in a phenomenological disguise, in connection with the description
of the index theorem for families, in the particular case relevant to gauge theories, but not
as mathematical prerequisites.

As a consequence of the principle of maximal
perversity, one may expect that physics will exhibit subtle effects describable in terms of
the above-mentioned constructions. In such an event, there remains the hope for a
corresponding textbook as understandable as this one, possibly written by the same
author.

Raymond Stora, LAPP, Annecy.

A Modern Introduction to Particle Physics

by Fayyazuddin and Riazuddin,
2nd edn, World Scientific ISBN 9810238762 hbk, ISBN 9810238770 pbk.

The
first edition of this book by the talented twins from Pakistan, which appeared in 1992, has
been updated, with the chapters on neutrino physics, particle mixing and CP violation,
and weak decays of heavy flavours having been rewritten. Heavy quark effective field
theory and introductory material on supersymmetry and strings are also included.