The Information - James Gleick [170]
13 | INFORMATION IS PHYSICAL
(It from Bit)
The more energy, the faster the bits flip. Earth, air, fire, and water in the end are all made of energy, but the different forms they take are determined by information. To do anything requires energy. To specify what is done requires information.
—Seth Lloyd (2006)♦
QUANTUM MECHANICS HAS WEATHERED in its short history more crises, controversies, interpretations (the Copenhagen, the Bohm, the Many Worlds, the Many Minds), factional implosions, and general philosophical breast-beating than any other science. It is happily riddled with mysteries. It blithely disregards human intuition. Albert Einstein died unreconciled to its consequences, and Richard Feynman was not joking when he said no one understands it. Perhaps arguments about the nature of reality are to be expected; quantum physics, so uncannily successful in practice, deals in theory with the foundations of all things, and its own foundations are continually being rebuilt. Even so, the ferment sometimes seems more religious than scientific.
“How did this come about?”♦ asks Christopher Fuchs, a quantum theorist at Bell Labs and then the Perimeter Institute in Canada.
Go to any meeting, and it is like being in a holy city in great tumult. You will find all the religions with all their priests pitted in holy war—the Bohmians, the Consistent Historians, the Transactionalists, the Spontaneous Collapseans, the Einselectionists, the Contextual Objectivists, the outright Everettics, and many more beyond that. They all declare to see the light, the ultimate light. Each tells us that if we will accept their solution as our savior, then we too will see the light.
It is time, he says, to start fresh. Throw away the existing quantum axioms, exquisite and mathematical as they are, and turn to deep physical principles. “Those principles should be crisp; they should be compelling. They should stir the soul.” And where should these physical principles be found? Fuchs answers his own question: in quantum information theory.
“The reason is simple, and I think inescapable,”♦ he declares. “Quantum mechanics has always been about information; it is just that the physics community has forgotten this.”
VISUAL AID BY CHRISTOPHER FUCHS (Illustration credit 13.1)
One who did not forget—or who rediscovered it—was John Archibald Wheeler, pioneer of nuclear fission, student of Bohr and teacher of Feynman, namer of black holes, the last giant of twentieth-century physics. Wheeler was given to epigrams and gnomic utterances. A black hole has no hair was his famous way of stating that nothing but mass, charge, and spin can be perceived from outside. “It teaches us,” he wrote, “that space can be crumpled like a piece of paper into an infinitesimal dot, that time can be extinguished like a blown-out flame, and that the laws of physics that we regard as ‘sacred,’ as immutable, are anything but.”♦ In 1989 he offered his final catchphrase: It from Bit. His view was extreme. It was immaterialist: information first, everything else later. “Otherwise put,”♦ he said,
every it—every particle, every field of force, even the space-time continuum itself—derives its function, its meaning, its very existence … from bits.
Why does nature appear quantized? Because information is quantized. The bit is the ultimate unsplittable particle.
Among the physics phenomena that pushed information front and center, none were more spectacular than black holes. At first, of course, they had not seemed to involve information at all.
Black holes were the brainchild of Einstein, though he did not live to know about them. He established by 1915 that light must submit to the pull of gravity; that gravity curves the fabric of spacetime; and that a sufficient mass, compacted together, as in a dense star, would collapse utterly, intensifying its own gravity and contracting without limit. It took