About one hundred years ago, the vast majority of scientists in the nascent field of quantum mechanics was ready to accept Niels Bohr’s dictum that “truth and clarity are complementary”.
That meant Louis de Broglie, Erwin Schrödinger, David Bohm and even the great Albert Einstein had to be wrong. Their unorthodox ideas of “ghost waves” and “hidden variables” were so at odds with the mainstream interpretations, that they weren’t even properly rebuked, but simply dismissed with silence.
That would all change with John Bell, some three decades later.
If you haven’t heard of Bell it’s because he died before his time. When last year’s Nobel prize in physics was awarded to Alain Aspect, John Clauser and Anton Zeilinger, it was for their experimental validation of Bell’s theorem.
But we’re getting ahead of ourselves, let’s back up to when John Bell arrived at CERN in the early 60’s. Here he is in the drably beige cafeteria, in a heated conversation with the theoretical physicist Josef-Maria Jauch:
Bell actually looked a little angry. He took a breath.
“Among the books I would like to write—” he said, and then smiled with irony. “I would like to write half a dozen books, which means I won’t write any.” He leaned back in his chair again. “But one of these books would trace the history of the hidden-variable question and especially the psychology behind people’s peculiar reactions to it. Why were people so intolerant of de Broglie’s gropings and of Bohm’s?”
Leaning forward, he said in a clear voice: “For twenty-five years, people were saying that hidden-variables theories were impossible. After Bohm did it, some of the same people said that now it was trivial. They did a fantastic somersault. First they convinced themselves, in all sorts of ways, that it couldn’t be done. And then it becomes ‘trivial’.”
He raised his hands off the table with a bemused expression.
The writer who makes this scene come so exquisitely to life, is Louisa Gilder. Her book The Age of Entanglement : When Quantum Physics Was Reborn brings the techniques of New Journalism to science reporting, meaning that she’s taking ample poetic liberty with details which combines to form a narrative, while at the same time sticking strictly to verifiable facts.
That is to say: even if you perhaps can’t necessarily trust that the CERN cafeteria was drably beige, or that John Bell raised his hands with a bemused expression, you can trust that every single utterance in Gilder’s book has in fact been expressed like so (Gilder goes on for some 60 pages declaring her sources).
One of the fascinating things with Gilder’s bok is that it doesn’t really have a plot, and yet it’s every bit as unputdownable as a fast-paced thriller.
Or perhaps it’s more accurate to say that there is indeed a plot of sorts, although it’s highly unconventional. Because what drives the story is decades worth of *really* smart people banging their heads against a wall which seems completely impenetrable, until it suddenly gives way.
Not that I could tell you exactly how that happens, even after ravishing Gilder’s book I’m still pretty much in the dark. (Let’s take comfort in the fact that the great Richard Feynman said “I think I can safely say that nobody understands quantum mechanics.”) But I *have* gained a valuable insight into how humanity’s collective understanding of this enigmatic field has evolved over time, and I feel that goes a long way.
I find it especially fascinating how things seems to have suddenly reached some sort of cognitive tipping point in the 90’s, perhaps as a consequence of how the pure science of quantum mechanics started to turn into applied engineering around this time. Here’s Nicolas Gisin, forerunner in the field of quantum communication:
“Quantum mechanics has now existed for about eighty-five years, and has mainly been considered as a theory of paradoxes, of mathematics, and strange counterintuitive ideas. So it was actually looked at from a quantitatively negative point of view—with rules like, you can not measure this and that simultaneously; you should not draw pictures of elementary quantum processess; you cannot clone a photon… all these are negative rules.
[…]Artur Ekert’s 1991 discovery of entanglement based quantum cryptography was the turning point. It changed physicist’s world: entanglement and quantum non-locality became respectable. What was negative became positive, ushering in a kind of psychological revolution among physicists (and actually only, of course, a fraction of the physicists—young ones mainly, also computer scientists) who began to realise that quantum mechanics being very different from classical physics also opens up the possibility for doing something that is radically new.”
Michael Nielsen and Isaac Chuang, authors of Quantum Computation and Quantum Information, one of the first ‘applied quantum’ textbooks have this to say:
“Quantum information science has revealed that entanglement is a quantifiable physical resource, like energy, that enables information-processing tasks: some systems have a little entanglement; others have a lot. The more entanglement is available, the better suited a system is to quantum information processing.”
Nielsen and Chuang go on to draw a parallell between the times we currently live in and the era of the steam engine, when the prosaic implementation of a novel technology was at once spawned by—and also accelerated—a deeper insight into the fundamentals of thermodynamics.
I loved The Age of Entanglement dearly. To the point in fact that I even hesitate to tell the world about this gem of a book; part of me wants to keep it to myself like a precious secret. It’s a mystery to me why it hasen’t gotten more attention, and especially why there seem to be almost *no* information available online about its brilliant young author, accept for this brief profile on Penguin Random House’s web. I wonder how it’s possible to write something so perfect, have it published as your first book, and then disappear so completely from the public eye. @Louisa: If you’re out there, please pick up the pen again!