Quantum Physics for Poets

Two decades ago, when I was on sabbatical at a US university, I was asked to teach the course Physics for Poets. No one told me that the title was a nickname for a basic course on physics for students who knew next to no science. It turned out that my audience consisted of geographers, historians, sociologists and baseball players masquerading as students - but not a poet in sight.

The origin of the Physics for Poets sobriquet - used for many other similar courses in the US - was unclear, but I gathered that it might be an allusion to the rather patronising notion that poets tend to have no science and an aversion to detail. I spent a rewarding term teaching that course and learned that non-specialists had a voracious appetite for the big ideas of physics, so long as they could be explained with mathematics that did not go much beyond long division. So numerous were these courses that in the US there were dozens of textbooks to choose from. Most stressed the relevance of science to everyday life, featuring hundreds of homely examples and even more colour photos to ram home the point that physics is "relevant".

Quantum Physics for Poets is in the tradition of this genre but it is not a reference book and, unusually, focuses almost exclusively on modern physics and on its abstract ideas. Applications have only a walk-on role. The book is the work of Christopher Hill, a theoretical physicist at Fermilab, and the Nobel laureate Leon Lederman, one of the finest experimenters of the past 60 years and a great champion of physics education in US schools. (The only blot on his career was his suggestion that the Higgs boson could be relabelled the "God particle".) In fewer than 300 pages, Hill and Lederman take us from Max Planck's discovery of the quantum at the turn of the 20th century, all the way to string theory and the possibility of quantum computers. It is quite a ride.

In the first half of the book, the authors review basic quantum theory. They do a good job of getting over the weirdness of the subatomic world, at least as judged by human beings familiar with matter on a much larger scale. Hill and Lederman gamely try to show how theory accounts for this weirdness, although this is not easy without complex numbers and calculus. Occasionally the prose is interspersed with gobbets of verse from poets of the calibre of Robert Frost, Emily Dickinson and the talented Anon, who contributes a perceptive description of the physicist Wolfgang Pauli: "When with his colleagues he debates/All his body oscillates/.../Dazzling theories he unveils/Bitten from his fingernails." Apart from these brief poetic interludes, the presentation is surprisingly orthodox and disappointingly lacking in Nobel-level pixie dust.

The book comes into its own in its second half, however. Hill and Lederman look in some depth at tests of modern interpretations of quantum mechanics, including an account of the test whose results suggest that even Albert Einstein's intuition was sometimes flawed. Readers who want to know more about the ideas being probed at the Large Hadron Collider will be pleased to find sections here on relativistic quantum theory and supersymmetry, all digestible by virtue of being well written and virtually devoid of scary mathematics. The authors even review the general theory of relativity and black holes, although by then the book has degenerated into a series of notes.

The authors are so preoccupied with covering all bases that they spend little time reflecting on today's hottest topics and thus do scant justice to them. One example is the energy of the vacuum. If today's standard theories are used to calculate it, the prediction turns out to be too big by 120 orders of magnitude, that is, 10¹²⁰. As Hill and Lederman point out: "This is often called the biggest mistake in physics!" The problem is that the authors are so busy scooting ahead that the significance of this point is all but lost.

Although it is no masterpiece, I recommend Quantum Physics for Poets to those who want a smooth helicopter ride over modern physics without fear of mathematics-induced travel sickness. Many readers curious about modern quantum physics will take a lot of pleasure from it, and would have taken even more if the authors had spent more time smelling the roses. My students would, I believe, have advised these authors to chill a little and make their case for the fascination of quantum theory rather less prosaic.