The cat who rode the wave

BIOGRAPHY:The great physicist Erwin Schrödinger, famous for his theory about the feline in the box, spent his happiest years in Dublin

Erwin Schrödinger and the Quantum Revolution By John Gribbin Bantam Press, 323pp. £25

God must be glad to see them play

Like kittens in the sun

Delighted with the wisps of hay

Blown from His haggard on a breezy day . . .

Time’s kittens, have your fun.

THIS SHORT POEM by Patrick Kavanagh is titled For Dr Schrödinger and Other Eminent Physicists, and it picks up on the well-worn trope of Schrödinger’s cat. Indeed, that feline familiar has featured in the titles of two previous books by John Gribbin, namely In Search of Schrödinger’s Cat and Schrödinger’s Kittens and the Search for Reality, first published in 1984 and 1995, respectively.

Gribbin is a significant name in the popularisation of science, and, with so much of the quantum story already in his portfolio, he is well qualified to talk about Schrödinger the man. But there already exists such a book, in Walter Moore’s exhaustive Schrödinger: Life and Thought (1989). Moore’s focus on Schrödinger is intense, replete with equations, snatches of poetry and a dissection of a personal life that is unequalled in the biography of any other scientist.

Gribbin’s focus is more diffuse. He justifies his book on particular and general grounds: the particular is “a prescient but little-known piece of work” by Schrödinger that pointed the way towards the latter-day hot topic of the multiverse; the general is the fact that Schrödinger’s life was of itself remarkable and worthy of “a popular biography”. The result is an entanglement (to borrow a Schrödinger term) of the story of a life and the story of the development of arguably the most successful and least understood theory of physics.

Gribbin strives to make that theory understandable at some level, and he largely succeeds, at least for the more tractable first revolution of Max Planck, Albert Einstein and Niels Bohr; Schrödinger was then just beginning his career as a physicist. Although it is possible with hindsight to trace some quantum novelties in an early paper by Schrödinger on electron orbits, it is Louis-Victor de Broglie’s 1924 assertion of wave-particle duality that steers him to the eponymous wave equation. As elsewhere in physics, luck played a role: an earlier version of the equation, which incorporated special relativity, failed miserably, whereas a subsequent version, leaving out special relativity, matched the experiment. The luck lay in the cancellation of the effect of special relativity by the then unknown effect of electron spin.

Whereas physicists word-associate Schrödinger with “equation”, the rest of us think “cat”. Between the dates of these two inventions lies a complex history of discussion about what the new physics might mean. On one side are Bohr and fellow travellers who championed the Copenhagen Interpretation; on the other, the heavyweight duo of Einstein and Schrödinger. In the latter’s paradox, the supposition that the mythical cat is both alive and dead until the box is finally opened is meant to point out the absurdity of “the collapse of the wavefunction” approach of the other side. The discussion has moved on since then, but the cat still flourishes in popular imagination.

All of this work was largely behind him when Schrödinger arrived in Dublin in 1939, at the invitation of the taoiseach, Éamon de Valera. He would stay for 17 years, a period he described as “the happiest years of my life”. Gribbin outlines the peripatetic journey towards this haven of political, financial and emotional security. Nelson-like, Dev turned a blind eye to the family consisting of wife, daughter and the daughter’s mother; there would be two further additions to the family, daughters of two other mothers.

Schrödinger was appointed director of the fledgling Dublin Institute for Advanced Studies, an entity that soon attracted the attention of Myles na gCopaleen’s Cruiskeen Lawn column in this newspaper. Following a talk by Schrödinger on causality and one by his fellow professor (of Celtic studies) on Palladius and Patrick, Myles quipped that the first fruits of the institute were that there two St Patricks and no God. Gribbin truncates this gem to exclude the Palladius reference, which dilutes the humour.

The Schrödingers hosted frequent parties at their home in Clontarf. They were active members of the artistic set in Dublin, with a particular interest in the theatre. Schrödinger refused to join the official condemnation of Myles’s irreverence, and the two became friends, with Schrödinger advising Myles on his adaptation of The Insect Play by the Capek brothers.

Under Schrödinger’s leadership, Dublin Institute of Advanced Studies rapidly gained an international reputation. It is fair to say that his research was not of the order of his earlier triumphs; like Einstein, he worked in the area of unified field theory. Probably his most significant contribution was to direct physicists towards biology – Francis Crick and James Watson, discoverers of the DNA double helix, both cite his book What Is Life? as a major influence on their work.

Gribbin’s penultimate chapter is titled “Schrödinger’s Scientific Legacy”. Here Einstein’s taunt of “spooky action at a distance” is defused by the intervention of the Belfast man John Bell. Employing Bell’s Inequality, a test to distinguish between competing interpretations, experiment has proved that there are no “hidden variables”; what you see in quantum physics is what you get. There then follows an even bumpier ride through quantum teleportation and related otherworldly effects, with the final offering that it might after all be “not so different from Schrödinger’s Vedantic vision of reality”.

Allowing for the difficulty of the subject matter, this is a rattling good read, though some might baulk at such offhand phrasing as “hairy mathematics” or the assertion that Schrödinger wrote “the kind of poetry you would expect a physicist to write”. The font size and the photographs are better than in Moore’s book. Moreover, those who stay the course are rewarded with a surprise ending. The book has the dedication: “For Terry Rudolf, even though he won’t read it.” The reason is revealed in the concluding chapter; to do so here would only, well, let the cat out of the bag.

Iggy McGovern is professor of physics at Trinity College Dublin. His most recent collection of poetry, Safe House, was published by Dedalus Press in 2010