Between the lines – Carlo Rovelli on Helgoland, quantum and the future of science
In the summer of 1925, the young physicist Werner Heisenberg suffered terribly from hay fever. For respite, he holed up on the island of Helgoland – Heligoland on the weather map – off the coast of Schleswig-Holstein in the North Sea. It had sparse vegetation, so minimal pollen. On around the night of 7 June, after hours of toil, he came up with the equation which was to change science and continues to shake our world today.
It related to the behaviour of electrons moving from one atom to another – this is the much misunderstood ‘quantum leap’. The electrons are in quanta – grains – and the pattern of behaviour was different in relation to the atoms they left, and the atoms they were joining. Heisenberg framed the equation in two sets of tables. As he waited for the sun to come up, he recalls, “looking into a strangely beautiful interior.”
His equation was the foundation of quantum mechanics, one of the greatest breakthroughs in theoretical physics. It stands on a par with Einstein’s general theory of relativity. It has led to a continuing revolution in science, and has growing resonance today; it made way to modern computing and the atomic bomb. This last week, quantum studies are at the heart of the scientific research and development programmes flagged by the UK’s new Integrated Review of Security, Defence, Development and Foreign Policy.
The story of quantum theory, its paradoxes and profundities, is told by Carlo Rovelli in Helgoland, a stunningly elegant work of literature, whose English translation is as sparkling as the original Italian. Rovelli himself is at the forefront of quantum study, teaching and researching in Italy, at Marseille, and in Canada. He is a superb craftsman at the explanation of science to specialists and non-specialists – this is his fourth book for an international audience. It is a masterpiece.
From the first, Rovelli recognizes that explaining the quantum revolution is a hard task at the best of times. It can be a bit of a mess – his words, not mine. It is full of grains of light and energy, things you can’t see – or if you do see them, they’ve already gone. There are crazy games with uncertainty – once you describe a thing, it has already changed, for a start – whether God plays dice, and puts cats in at least two places at once, alive, asleep, or even dead.
Quantum is about relationships. Phenomena exist at the sub-atomic level only as they relate to other things. These are known as ‘entanglements’, which lead to the huge speed and power of quantum computing, at which the Chinese now lead the world. It also raises the possibility, and probability, of teleporting.
“The paper Heisenberg produced in 1925 marked a dramatic shift of perspective on how atoms work. He did it in one elegant move, with the equation,” Carlo Rovelli explained to me in a recent phone call from Canada. “He did it in one smart stroke; it worked fantastically – and it has never been challenged.”
In contrast to classical physics, “a wonderful, beautiful display for all to see,” quantum mechanics is obscure , and “opens a deep abyss.” In a brilliant opening disclaimer, the author levels about the paradox of his book. “I have tried to be as clear as possible, about a theory that is at the centre of the obscurity of science,” he writes. “Perhaps rather than explaining how to understand quantum mechanics, I explain why it is so difficult to understand.”
Heisenberg did not work in isolation – he was sponsored and promoted by established physicists such as the Dane Niels Bohr, who won the Nobel prize in 1920, and Max Born, who was to win in 1954. Born had helped prepare the papers for which Heisenberg would win the Nobel Prize for ‘the invention of quantum mechanics’ in 1932. Another remarkable figure, who stalks through Rovelli’s pages with his legendary cat, is Erwin Schrödinger, who won the prize the following year. He argued that particles of electro-energy, photons, travelled in waves. This has led to much discussion.
By 1927, Heisenberg had established his uncertainty principle – that much of what he was proposing could not be observed, because of the constant movement and churn of the subatomic world. It depends on the interaction of the observer and the observed – relationship, or entanglement – a major theme for the latter half of this book.
This underlies Shrödinger’s most famous thought game. The notion of ‘superposition’ in quantum physics holds that something can be recognised in several places at once. Schrödinger proposed that a cat could either be sleeping (or even dead) in a box or bouncing around, fully awake. Rovelli has great fun playing with Schrödinger’s hyper-active feline.
Confused? Well, you are in very good company – and the author says you have every right to be. “The quantum world is more tenuous than the one imagined by the old physics,” he declares in a glorious purple passage. “It is made up of happenings, discontinuous events, without permanence. It is a world with a fine texture, intricate and fragile as Venetian lace.”
One of the early critics of what Heisenberg produced was Albert Einstein, who earlier had done much to promote quantum research. In correspondence with Niels Bohr he deplored the lack of precision in the overall theory – with its bias to conjecture, probability and imagination, thus generating one of the most famous remarks of the whole story. “Quantum mechanics is certainly imposing,” Einstein wrote, “but an inner voice tells me that it is not yet the real thing. The theory says a lot, but it does not bring us any closer to the secret of the ‘Old One’ – the terms in which Einstein, the atheist, referred to God. I, at any rate, am convinced that He is not playing at dice.” To which came Bohr’s put-down, “Stop telling God what to do.”
“They were great friends, and the correspondence went on for years. Einstein did come round to the Heisenberg view,” Carlo Rovelli says. “But Bohr is often underestimated. In his range and depth, and humanity, for me he is one of the greatest figures of science. He had such a wide understanding of the general problem of science – Bohr thought he was a philosopher more than a physicist.”
In September 1941, Heisenberg travelled to meet Bohr in occupied Denmark. By then he was in charge of Hitler’s nuclear weapons programme. The meeting is the subject of Michael Frayn’s play Copenhagen, though there is no actual record of what was discussed. Neither scientist was to speak about it in detail. Bohr, however, could not disguise afterwards that he was visibly shaken and upset by the encounter. The inference is that Heisenberg had said that Germany would have an atomic weapon by 1945, and might then win the war. Rovelli records this evidently painful incident, but does not comment.
In 1943, Bohr fled to Sweden as it was certain he and his family were about to be rounded up; his mother was Jewish. From Sweden he was smuggled in the bomb bay of a Mosquito in an excruciatingly uncomfortable three hour flight to England. Bohr’s generous spirit, and deep and deeply humane approach infuses Rovelli’s writing. “One of the most wonderful things is the vagueness of some of Bohr’s speculation.” This leads Rovelli into illuminating discussion about the nature of the self as an observer, the nature and meaning of observation, the meaning of meaning even, and what lies at the bottom of the abyss of experience and the universe.
And yes, we do have an approving reference to Douglas Adams and The Hitchhiker’s Guide to the Galaxy, and its take on life, the universe and everything. The story of scientific inquiry reaches back to the ancient world of Anaximander, Rovelli’s hero, Empedocles and Democritus who mused that, “the cosmos is change, life is discourse,” in one of the remaining fragments of his writing. Most of all Rovelli’s speculations recall the spirit, substance and style of the Roman Lucretius in his great poem The Nature of Things.
These in the language of philosophy
It is our custom to describe as matter
Or generative bodies, or seeds of things,
Or call them primal atoms, since from them,
Those first beginnings, everything is formed.
(On the Nature of the Universe, Lucretius, World Classics ll 58-60)
In his wit, joy of puns and paradoxes and speculation and imagination about meaning and existence, Rovelli also conjures the spark of a fellow Italian free spirit, Italo Calvino – especially in his great puzzle pieces , Invisible Cities, The Castle of Crossed Destinies, and If on a Winter’s Night, a Traveller’ Calvino would have loved this book, and on my bookshelf it will sit next to his masterpieces.
I ask Carlo Rovelli if his mission was to bring a better understanding of the sciences to a broader public, if those educated in the arts and humanities and the applied sciences even, needed a better grounding in general science? “Helping a broad understanding is very important, but I don’t think we should go too far in this. We don’t want cut back excellence in other fields in education and expertise – they are important, too. We shouldn’t be too extreme,” he says.
Contemplating the abyss, the most vertiginous of Nature’s secrets, as he describes Heisenberg’s discovery on Helgoland, Rovelli has found solace in interesting places. Worrying about where his own quantum researchers were pointing, and what they suggested about life, the universe, science, meaning, the meaning of meaning, he sought guidance. This leads to the joyous, and somewhat unexpectedly disconcerting, concluding passage of the book.
One guide was a text, The Middle Way, written in the second century CE by the Buddhist sage Nagarjuna, which in many ways foreshadows the core of quantum theory. “There are no elementary entities that we can describe,” the monk wrote, “except in the context of their interaction with something else.” So what is fundamental? Rovelli gives a list of unsatisfactory answers from western philosophy before addressing Nagarjuna’s response. This makes it easier to think about the quantum world. Since nothing exists independently, says the monk, we are left with absence, emptiness – Sunyata. This relates to the illusoriness of the world, Samsara, a concept central to Buddhism. Understanding this helps the passage to the liberation and beatitude of Nirvana. Emptiness is empty.
This is also the message of Prospero in his farewell in The Tempest – “Our revels now are ended.” This is less Shakespeare’s farewell to a life of the stage, suggests Rovelli, but Shakespeare’s profound and instinctive understanding of the quantum universe. “Of course Shakespeare’s world is real,” Carlo Rovelli says at the end of our conversation, “but he understands the illusory aspect of reality. Across his plays we see screens, and screens behind screens. He gives us the dreamy aspect of reality.
We are such stuff
As dreams are made on, and our little life
Is rounded with a sleep
(The Tempest, Act 4, Scene 1)
A few years back there was a wonderful, and no doubt apocryphal, story about the poet TS Eliot and a London taxi driver. “Hello,” says the driver, “I have seen you on the telly – Brains Trust – with that Lord (Bertrand) Russell. I had him in the cab, the brainiest bloke in the world. So I said, “you are the brainiest person in the world, Lord Russell, so what’s it all about? Everything, what’s it all about?” And he didn’t know – the brainiest bloke in the world didn’t know.”
The driver might find at least some of the answer in Carlo Rovelli’s Helgoland. It’s a gem of a book, with a touch of genius.
