The Universe Within (24 page)

A quantum computer works in an entirely different way. Its memory is composed of qubits, short for quantum bits. Qubits are somewhat like classical bits in that when you read them out, you get either 0 or 1. However, the resemblance ends there. According to quantum
theory
, the typical state for a qubit is to be in a
superposition
— a state consisting
of 0 and 1 at the same time. The amount of 0 or 1 in the state indicates how probable it is to obtain 0 or 1 when the qubit is read.

The fact that the state of a qubit is specified by a continuous quantity — the proportion of 0 or 1 in the state — is a clue that it can store infinitely more information than a classical bit ever can.
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The situation gets even more interesting when you have more than one qubit and their states are
entangled
. This means that, unlike classical bits, qubits cannot be read independently: what you measure for one of them will influence what you measure for the other. For example, if two qubits are entangled, then the result you obtain when you measure one of them will completely determine the result you obtain if you measure the other. A collection of entangled qubits forms a whole that is very much greater than the sum of its parts.

Shor used these features to make prime-number factoring go fast. Classically, if you tried to find the prime factors of a large number,
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the brute force method would be to divide it by two as many times as you could, then three, then five, and so on, and keep going until no further divisions worked. However, what Shor realized, in essence, is that a quantum computer can perform all of these operations at the same time. Because the quantum state of the qubits in the computer simultaneously encodes many different classical states, the computations can all occur “in parallel,” dramatically speeding up the operation.

Shor's discovery launched a global race to build a quantum computer, using a wide range of quantum technologies: atomic and nuclear spins, the polarization states of light, the current-carrying states of superconducting rings, and many other incarnations of qubits. In recent years, the race has reached fever pitch. At the time of writing, researchers at
IBM
are claiming they are close to producing a “scalable” quantum computing technology.

What will this vast increase in our information-­handling capabilities mean? It is striking to compare our situation today, with the vast libraries at our fingertips and far vaster ones to come, with that of the authors of the modern scientific age. In the Wren Library in Trinity College, Cambridge, Isaac Newton's personal library consists of a few hundred books occupying a single bookcase. This was quite enough to allow him to found modern physics and mathematical science. A short walk away, in the main University Library, Charles Darwin's personal library is also preserved. His entire collection of books occupies a ten-metre stretch of shelving. Again, for one of the most profound and original thinkers in the history of science, it is a minuscule collection.

Today, on your smartphone, you can access information resources vastly greater than any library. And according to Moore's law, in a couple of decades your laptop will comfortably hold every single book that has ever been written. A laptop quantum computer will seem more like Jorge Luis Borges's Library of Babel — a fantastical collection holding every possible ordering of letters and words in a book, and therefore every book that could ever be written. With a quantum library, one might instead be able to search for all possible interesting passages of text without anyone having had to compose them.

Some of the uses of quantum computers and quantum communication are easy to anticipate. Ensuring the security of information is one of them. The codes currently used to protect access to bank accounts, computer passwords, and credit card information rely on the fact that it is hard to find the prime factors of large numbers using a classical computer. However, as Peter Shor showed, quantum computers will be able to quickly find these factors, rendering current security protocols obsolete. Also, quantum information is inherently safer from attack than classical information, because it is protected by the fundamental laws of physics. Whereas reading out classical information does nothing to change it, according to quantum physics, the mere fact of observing a quantum system almost always changes its quantum state. Through this effect, eavesdropping or hacking into quantum information can be detected. Hence quantum information can be made invulnerable to spying in ways that would be classically impossible.

Quantum computers may also transform our capacities to process data in parallel, and this could enable systems with great social benefit. One proposal now being considered is to install highly sensitive biochemical quantum detectors in every home. In this way, the detailed medical condition of every one of us could be continuously monitored. The data would be transmitted to banks of computers which would process and screen it for any signs of risk. The results of any medical treatment or dietary change or any other intervention would be constantly gathered. With access to such vast amounts of data and information-processing power, medicine would be revolutionized. We would all be participants in medical trials, on a scale and with an accuracy and breadth greater than anything seen before.

But by far the greatest impact quantum computers will have is likely to be on ourselves.

· · ·

THE IDEA THAT OUR
communication technologies change us was emphasized by the Canadian communications guru Marshall McLuhan. McLuhan's 1964 book,
Understanding Media: The Extensions of Man
, kicked off a wave of interest in the uses of mass media in all forms, from pop music and television to major corporations. McLuhan's writing is more poetic than analytical, but his basic insight was that the information content of all of these forms of mass media — from ads to games, cars, typewriters (remember, no PCs then!), books, telephones, newspapers, and so on — is less important than their physical form and their direct hold on our behaviour. He summed up this idea in his famous aphorism “The medium is the message.” Today, watching people wander around, eyes glued to smartphones, texting or emailing, in the grip of their gadgets and nearly oblivious to their surroundings, you can see what he meant.

McLuhan's point was that media have been having this effect on us for millennia. If you think for two seconds, it is amazing, and faintly ridiculous, that the mere act of compressing, and so severely limiting, our ideas in writing — in the case of European languages, into words written in an alphabet of twenty-six letters — has proven to be such a powerful and society-dominating technology. Writing is a means of extracting ourselves from the world of our experience to focus, form, and communicate our ideas. The process of committing ourselves to texts — from the scriptures to textbooks, encyclopedias, novels, political pamphlets, laws, and contracts — and then allowing them to control our lives has had an enormous and undeniable effect on who we are. McLuhan argued that print altered our entire outlook, emphasizing our visual sense, thus influencing the fragmentation and specialization of knowledge, and fostering everything from individualism to bureaucracy to nationalistic wars, peptic ulcers, and pornography.

McLuhan saw every mass medium, whether print, photography, radio, or TV, in a similar way: as an extension of our own nervous system, dramatically altering our nature and hence our society. “We have never stopped drastically interfering with ourselves by every technology we could latch on to,” he said in “The Future of Man in the Electric Age.” “We have absolutely disrupted our lives over and over again.”
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McLuhan accurately foresaw that electronic media would be combined with computers to spread information cheaply and instantly around the world, in a variety of forms. Thirty years before the internet was launched, he wrote: “The next medium, whatever it is — it may be the extension of consciousness — will include television as its content, not as its environment, and will transform television into an art form. A computer as a research and communication instrument could enhance retrieval, obsolesce mass library organization, retrieve the individual's encyclopedic function and flip into a private line to speedily tailored data of a saleable kind.”
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Furthermore, McLuhan argued optimistically that we might regain the breadth of our senses which the printed word had diminished, restoring the preliterate “tribal balance” between all of our senses through a unified, “seamless web” of experience. As electronic communication connected us, the world would become a “global village” — another of McLuhan's catchphrases.

McLuhan owed a pronounced intellectual debt to a visionary and mystic who came before him: Teilhard de Chardin. A Jesuit priest, a geologist, and a paleontologist who played a role in the discovery of Peking man, de Chardin took a very big-picture view of the universe and our place within it, a picture that encompassed and motivated some of McLuhan's major insights. De Chardin also foresaw global communications and the internet, writing in the 1950s about “the extraordinary network of radio and television communication which already link us all in a sort of ‘etherised' human consciousness,” and “those astonishing electronic computers which enhance the speed of thought and pave the way for a revolution in the speed of research.” This technology, he wrote, was creating a “nervous system for humanity,” a “stupendous thinking machine.” “The age of civilisation has ended,” he said, “and the age of
one civilisation
is beginning.”
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These ideas were an extension of de Chardin's magnum opus,
The Phenomenon of Man
. He completed the manuscript in the late 1930s, but because of his heterodox views, his ecclesiastical order refused throughout his lifetime to permit him to publish any of his writings. So de Chardin's books, and many collections of his essays, were only published after his death in 1955.

In spite of being a Catholic priest, de Chardin accepted Darwinian evolution as fact, and he built his futuristic vision around it. He saw the physical universe as in a state of constant evolution. Indeed,
The Phenomenon of Man
presents a “history of the universe” in terms that are surprisingly modern. De Chardin was probably influenced in this by another Jesuit priest, the founder of the hot big bang cosmology, Georges Lemaître.

De Chardin describes the emergence of complexity in the universe, from particles to atoms to molecules, to stars and planets, complex molecules, living cells, and consciousness, as a progressive “involution” of matter and energy, during which the universe becomes increasingly self-aware. Humans are self-aware and of fundamental significance to the whole. De Chardin quotes with approval Julian Huxley, who stated that “Man discovers that
he is nothing else than evolution become conscious of itself
.”
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Huxley was the grandson of T. H. Huxley, the biologist famously known as “Darwin's bulldog” for his articulate defence of evolutionary theory in the nineteenth century. He was also one of the founders of the “modern evolutionary synthesis,” linking genetics to evolution. De Chardin took Huxley's statement to a cosmic scale, envisioning that human society, confined to the Earth's spherical surface, would become increasingly connected into what would be in effect a very large living cell. With its self-consciousness and its inventions, it would continue to evolve through non-biological means towards an ultimate state of universal awareness, which he called the “Omega Point.”

De Chardin's arguments are vague, allusive, and (despite his claims) necessarily unscientific, since many key steps, such as the formation of cells and life, and the emergence of consciousness, are well beyond our scientific understanding, as, of course, is the future. His vision is nonetheless interesting for the way in which it sees in evolution a latent potential for progress towards increasing complexity within the physical substance of the world. This potential is becoming increasingly evident as human advancement through technology and collaboration supercedes survival of the biologically fittest as the driver of evolutionary progress. As Huxley says in his introduction to de Chardin's book, “We, mankind, contain the possibilities of the earth's immense future, and can realise more and more of them on condition that we increase our knowledge and our love. That, it seems to me, is the distillation of
The Phenomenon of Man
.”
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McLuhan and de Chardin accurately foresaw the digital age and the future impact of electronic communication on the evolution of society. As McLuhan put it, “The medium, or process, of our time — electric technology — is reshaping and restructuring patterns of our social interdependence and every aspect of our personal life . . . Everything is changing — you, your family, your neighbourhood, your job, your government, your relation to ‘the others.' And they're changing dramatically.” He also foresaw some of the features and dangers of the internet and social media. He described an “electrically computerized dossier bank — that one big gossip column that is unforgiving, unforgetful, and from which there is no redemption, no erasure of early ‘mistakes.'”
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These comments are insightful. They point to the clash between digital information and our analog nature. Our bodies and our senses work in smooth, continuous ways, and we most appreciate music or art or natural experiences that incorporate rich, continuous textures. We are analog beings living in a digital world, facing a quantum future.

DIGITAL INFORMATION IS THE
crudest, bluntest, most brutal form of information that we know. Everything can be reduced to finite strings of 0s and 1s. It is completely unambiguous and is easily remembered. It reduces everything to black and white, yes or no, and it can be copied easily with complete accuracy. Obviously, analog information is infinitely richer. One analog number can take an infinite number of values, infinitely more values than can be taken by any finite number of digital bits.