by Neil Turok
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.” 90
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.”91 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.”92
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.”93 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.”94
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.’”95
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.
The transition from analog to digital sound — from records and tapes to CDs and MP3s — caused a controversy, which continues to this day, about whether a digital reproduction is less rich and interesting to listen to than an analog version. By using more and more digital bits, one can mimic an analog sound to any desired accuracy. The fact remains that analog sound is inherently more subtle and less jarring than digital. Certainly, even in this digital age, analog instruments show no signs of going out of fashion.
Life’s DNA code is digital. Its messages are written in three-letter “words” formed from a four-letter alphabet. Every word codes for an amino acid, and each sentence codes for a protein, made up of a long string of amino acids. The proteins form the basic machinery of life, part of which is dedicated to reading and transcribing DNA into yet more proteins. Although it is indeed amazing that all of the extravagant diversity and beauty of life is encoded in this way, it is also important to realize that the DNA code itself is not in any way alive.
Although the genetic basis for life is digital, living beings are analog creatures. We are made of plasmas, tissues, membranes, controlled by chemical reactions that depend continuously on concentrations of enzymes and reactants. Our DNA only comes to life when placed in an environment with the right molecules, fluids, and sources of energy and nutrients. None of these factors can be described as digital. New DNA sequences only arise as the result of mutations and reshufflings, which are partly environmental and partly quantum mechanical in origin. Two of the key processes that drive evolution — variation and selection — are therefore not digital. The main feature of the digital component of life — DNA — is its persistent, unambiguous character; it can be reproduced and translated into RNA and protein accurately and efficiently. The human body contains tens of trillions of cells, each with an identical copy of the DNA. Every time a cell divides, its DNA is copied.
It is tempting to see the digital DNA code as the fundamental basis of life, and our living bodies as merely its “servants,” with our only function being to preserve our DNA and to enable its reproduction. But it seems to me that one can equally well argue that life, being fundamentally analog, uses digital memory simply to preserve the accuracy of its reproduction. That is, life is a happy combination of mainly digital memory and mainly analog operations.
At first sight, our nerves and brains might appear to be digital, since they either fire or do not in response to stimuli, just as the basic digital storage element is either 0 or 1. However, the nerve-firing rate can be varied continuously, and nerves can fire either in synchrony or in various patterns of disarray. The concentrations and flows of biomolecules involved in key steps, such as the passage of signals across synapses, are analog quantities. In general, our brains appear to be much more nuanced and complex systems than digital processors. This disjuncture between our own analog nature and that of our computers is quite plausibly what makes them so dissatisfying as companions.
Although analog information can always be accurately mimicked by using a sufficient number of digital bits, it is nevertheless a truism that analog information is infinitely richer than digital. Quantum information is infinitely richer again. Just one qubit of quantum information is described by a continuum of values. As we increase the number of qubits, the number of continuous values required to describe them grows exponentially. The state of a 300-qubit quantum computer (which might consist of a chain of just 300 atoms in a row) would be described by more numbers than we could represent in an analog manner, even if we used the three-dimensional position of every single one of the 1090 or so particles in the entire visible universe.
The ability of physical particles to carry quantum information has other startling consequences, stemming from entanglement, in which the quantum state of two particles is intrinsically interlinked. In Chapter Two, I described how, in an Einstein–Podolsky–Rosen experiment, two particles fly apart with their spins “entangled,” so that if you observe both particles’ spin along some particular axis in space, then you will always find one particle’s spin pointing up while the other points down. This correlation, which Einstein referred to as “spooky action at a distance,” is maintained no matter how far apart the particles fly. It is the basis for Bell’s Theorem, also described in Chapter Two, which showed that the predictions of quantum theory can never be reproduced by classical ideas.
Starting in the 1980s, materials have been found in which electrons exhibit this strange entanglement property en masse. The German physicist Klaus von Klitzing discovered that if you suspend a piece of semiconductor in a strong magnetic field at a very low temperature, then the electrical conductance (a measure of how easily electric current flows through the material) is quantized. That is, it comes in whole number multiples of a fundamental unit. This is a very strange result, like turning on a tap and finding that water will flow out of it only at some fixed rate, or twice that rate, or three times the rate, however you adjust the tap. Conductance is a property of large things: wires and big chunks of matter. No one expected that it too could be quantized. The importance of von Klitzing’s discovery was to show that in the right conditions, quantum effects can still be important, even for very large objects.
Two years later, the story took another twist. The German physicist Horst Störmer and the Chinese physicist Dan Tsui, working at Bell Labs, discovered that the conductance could also come in rational fractions of the basic unit of conductance, fractions like 1⁄3, 2⁄5, and 3⁄7. The U.S. theorist Robert Laughlin, working at Stanford, interpreted the result as being due to the collective behaviour of all the electrons in the material. When they become entangled, they can form strange new entities whose electric charge is given in fractions of the charge of an electron.
Ever since these discoveries, solid state physicists have been discovering more and more examples of systems in which quantum particles behave in ways that would be classically impossible. These developments are challenging the traditional picture of individual particles, like electrons, carrying charge through the material. This picture guided the development of the transistor, but it is now seen as far too limited a conception of the possible states of matter. Quantum matter can take an infinitely greater variety of forms. The potential uses of these entirely new states of matter, which, as far as we know, never before formed in the universe, are only starting to be explored. They are likely to open a new era of quantum electronics and quantum devices, capable of doing things we have never seen before.
IN THE EARLY TWENTIETH century, the smallest piece of matter we knew of was the atomic nucleus. The largest was our galaxy. Over the subsequent century, our most powerful microscopes and telescopes have extended our view down to a ten-thousandth the size of an atomic nucleus and up to a hundred thousand times the size of our galaxy.
In the past decade, we have mapped the whole visibl
e universe out to a distance of nearly fourteen billion light years. As we look farther out into space, we see the universe as it was longer and longer ago. The most distant images reveal the infant universe emerging from the big bang, a hundred-thousandth of its current age. It was extremely uniform and smooth, but the density of matter varied by around one part in a hundred thousand from place to place. The primordial density variations appear to take the same form as quantum fluctuations of fields like the electromagnetic field in the vacuum, amplified and stretched to astronomical scales. The density variations were the seeds of galaxies, stars, planets, and, ultimately, life itself, so the observations seem to be telling us that quantum effects were vital to the origin of everything we can now see. The Planck satellite, currently flying and due to announce its results soon, has the capacity to tell us whether the very early universe underwent a burst of exponential expansion. Over the coming decades, yet more powerful satellite observations may be able to tell whether there was a universe before the big bang.
Very recently, the Large Hadron Collider has allowed us to probe the structure of matter on the tiniest scales ever explored. In doing so, it has confirmed the famous Higgs mechanism, responsible for determining the properties of the different types of elementary particles. Beyond the Large Hadron Collider, the proposed International Linear Collider will probe the structure of matter much more accurately on these tiniest accessible scales, perhaps revealing yet another layer of organization, such as new symmetries connecting matter particles and forces.
With experiments like the Large Hadron Collider and the Planck satellite, we are reaching for the inner and outer limits of the universe. Equally significant, with studies of quantum matter on more everyday scales, we are revealing the organization of entangled levels of reality more subtle than anything so far seen. If history is any guide, these discoveries will, over time, spawn new technologies that will come to dominate our society.