By Frank Close
Oxford University Press
Hardback: £16.99
Frank Close is a prolific author – Neutrino, Antimatter, Nothing, The New Cosmic Onion, Void, The Particle Odyssey, Lucifer’s Legacy and more, have already appeared this century. The Infinity Puzzle is his ingenious name for the vital but recondite procedure called “renormalization” in physics-speak, but his latest book covers much more ground than just this.
Setting off to trace the evolution of quantum field theory in the 20th century, Close needs to run, leaping from Niels Bohr to Paul Dirac without pausing at Erwin Schrödinger and Werner Heisenberg. However, he occasionally pauses for breath: his descriptions of difficult ideas such as gauge invariance and renormalization are themselves valuable. Equally illuminating are the vivid portraits of some of the players, many major – Abdus Salam, Sheldon Glashow, Gerard ’t Hooft and John Ward – as well as others, such as Ron Shaw, who played smaller roles. Other key contributors, notably Steven Weinberg, appear on the scene unheralded.
The core of the book is the re-emergence in the 1960s of field theory, which had lapsed into disgrace after its initial triumph with quantum electrodynamics. Its new successes came with a unified electroweak theory and with quantum chromodynamics for the strong interactions.
Embedded in this core is a scrutiny of spontaneous symmetry breaking as a physics tool. Here Close presents the series of overlapping contributions that led to the emergence of what is now universally called the “Higgs mechanism”, together with the various claims and counterclaims.
Electroweak unification gained recognition through the Nobel Prize in Physics twice: in 1979 with Glashow, Salam and Weinberg; and in 1999 with ’t Hooft and Martinus Veltman. Having assigned credit where he sees fit, Close also confiscates much of that accorded to Salam, stressing the latter’s keen ambition and political skills to the detriment of enormous contributions to world science. (His International Centre for Theoretical Physics in Trieste was launched with initial support from IAEA, not from UNESCO, as stated in the book.)
In this electroweak saga, Close gives an impression that understanding weak interactions was at the forefront of people’s minds in the mid-1960s, when many were, in fact, initially blinded by the dazzle of group theory for strong interactions and the attendant quark picture. In those days, spontaneous symmetry breaking became muddled with ideas of approximate symmetries of strong interactions. Many struggled to reconcile the lightness of the pion with massless Goldstone bosons. Close mentions Weinberg’s efforts in this direction and the sudden realization that he had been applying the right ideas to the wrong problem.
As the electroweak theory emerged, its protagonists danced round its renormalization problems, whose public resolution came in a 1971 presentation in Amsterdam by ’t Hooft, carefully stage-managed by Veltman, which provides a dramatic prologue to the book. For the strong interactions, Close sees Oxford with Dick Dalitz as a centre of quark-model developments but there was also a colourful quark high priest in the form of Harry Lipkin of the Weizmann Institute.
With the eponymous puzzle resolved, the book concludes with discoveries that confirmed the predictions of field theory redux and the subsequent effort to build big new machines, culminating in the LHC at CERN. The book’s end is just as breathless as its beginning.
The Infinity Puzzle is illustrated with numerous amusing anecdotes, many autobiographical. It displays a great deal of diligent research and required many interviews. At some 400 pages, it is thicker than most of Close’s books. Perhaps this is because there are really two books here. One aims at the big audience that wants to understand what the LHC is and what it does, and will find the detailed field-theory scenarios tedious. On the other hand, those who will be enlightened, if not delighted, by this insight will already know about the LHC and not need explanations of atomic bar codes.
