Quantum computing and the real: Ontological implications

In an engrossing (pun intended) article in the most recent TIME magazine (February 17), Lev Grossman wrote about the “Infinity Machine – Quantum Leap” (pp. 28-35). A revolutionary new kind of computer is introduced to those who are willing to expand their minds in an effort to understand it. Admittedly, this is a mainstream magazine, and allowances are made for accessibility, but it is still mind-challenging stuff — when has the theoretical domain of quantum mechanics and its applications NOT been challenging?

Some people may have heard of Schrödinger’s Cat — a thought experiment that illustrates what things are like in the “quantum universe”, with its puzzling “superposition” (TIME, p. 30). Imagine a cat being put in a sealed box with a container of poison and a source of radiation. There is a 50/50 chance of radioactive particles escaping from the source, and if that happens, the poison-container would shatter, and the released poison would cause the cat to die. In terms of quantum mechanics laws, the cat is “in superposition”, that is, alive and dead at the same time (which is unthinkable in everyday reality, although zombie movies come to mind), until the moment that the box is opened and it is “observed”, which settles the matter either way under conditions of a “classical state” (physics).

This is a picturesque way of saying what Werner Heisenberg, one of the other major figures in quantum mechanics, meant when he remarked, around the middle of the 20th century, that the very fact of “observing” the world “changes it”. In other words, the world, as it is independently of human beings observing it, is unimaginably different from the way it appears when we do perceive it by means of our sensory faculty, or senses, and could be — like Schrödinger’s Cat — different, widely divergent things at the same time. (Apart from quantum mechanics, this is the terrain of what is today known as complexity theory.) This is so counter-intuitive that I would not blame readers to stop reading this post immediately. But carry on if you want to know what computing has to do with it.

In the article concerned, Grossman introduces one to a Canadian computer firm called D-Wave, which produces computers of which the D-Wave Two is the “flagship”. There are only five of these at present, partly because they are impossibly expensive — about US$10 million each — and even more importantly, they only operate under extremely cold conditions; so cold, that it is a whisker from absolute zero, to wit -273.1 degrees Centigrade. This is the temperature required by the niobium chip inside the cooling cylinder. Just for the record, this is about one degree colder than what was believed to be the coldest known place in universe, Boomerang Nebula, about 5000 light years from Earth.

So what is so special about these computers, developed by Canadian physicist Geordie Rose and his company? To put it in terms simple enough for myself to understand, they differ from ordinary, “classical” computers in important ways. A “classical” computer works with “bits” (single units of information) in a binary, linear fashion — where every bit works according to the logic of either 1 or 0. The computers we know operate like this, and no matter whether you have a “supercomputer” or not, it cannot avoid working its way through masses of information along the lines of this either/or logic.

By contrast, a quantum computer operates with “qubits” according to the quantum logic of “both/and”. The data of ordinary, “classical” computers are assumed to exist in relatively stable, singular or unitary states, and they process these data linearly, or one by one, however fast. But quantum computers are built to work with information existing in “multiple states”, and must therefore, correspondingly, be able to perform multiple operations simultaneously, that is, not one by one in linear format.

It is not surprising that people have drawn connections between quantum theory and parallel universes — after all, if a quantum bit (qubit), in “superposed” condition, represents two or more possibilities that are equally probable, those possibilities exist, “ontologically” speaking (that is, regarding their mode of being), in different universes. For computer people, as well as for Nasa, for the CIA and for the NSA (among others), the technical advantage of multiple quantum calculations is that they can be performed at the same time.

Incidentally, in mathematical terms this was the theme of Daryn Aronofsky’s early film, a very original neo-noir called Pi, in which the noir detective was a mathematician looking for the formula “for everything”, and was predictably hounded by Wall Street types, as well as by religious fanatics — there’s a resemblance between these two groups — who thought they could use this “absolute” formula for failsafe investments and for finding God, respectively. Not surprisingly, therefore, Grossman lists stock trading as one of the areas where quantum computers can solve problems that “normal” computers cannot.

The other fields where Q-computers are in demand include surveillance practices (such as those associated with the NSA), medicine, software design and problem-solving of all kinds, such as the most time-economising route among several destinations. If they work, they can probably solve problems — at least abstractly — that are far more complex than those found in these fields. The D-Wave Two is equipped with 512 qubits, and could therefore theoretically perform 2 to the 512th power operations at the same time. As Grossman reminds one, this represents more calculations than there are atoms in the physical universe.

What interests me about this, is the way that the quantum-theoretical underpinnings of these computing developments validate Immanuel Kant’s notion of the Ding-an-sich or “thing-in-itself”, which is the “noumenal” reality “behind” the “phenomenal” reality of the things we ordinarily know in space and time. Kant postulated this realm of noumena because he argued that what we know is determined in its appearance and intelligibility by our own rational faculties — sensorily and intellectually — and what these phenomena are like, outside of our knowledge of them, must forever remain a mystery: they have multiple possibilities of being. The resemblance between this and what quantum logic points to must be clear in ontological terms. (Heisenberg’s remark, referred to earlier, about humans changing what is there, in the world, just by observing it, also resonates with Kant’s claims.)

In the case of the ontology or theory of being suggested by Jacques Lacan’s theory of the subject — which has a lot in common with Kant’s ontology and epistemology or theory of knowledge — the implications are even more intriguing. Lacan presents the subject as being precariously articulated between three registers or “orders” — the real, the imaginary and the symbolic. The imaginary is the register of the ego, because of the “image” with which you identify; the symbolic is that of language as discourse (essential for the social bond), and the most puzzling of the three, the “real”, points to the register of what surpasses language, what cannot be said, even when we struggle to, as when we have been traumatised, and we keep on trying to say what happened to us, but cannot do it adequately.

Unlike Kant’s Ding-an-sich, which stands “behind” the phenomenon in space and time, the “real” is not “behind” everything that is named in language. Rather, it shows itself within language itself, as an “internal limit” (as Joan Copjec points out in Imagine There is No Woman), as “not-being-able-to-name-it” or say “it”, or something, conclusively. We always say more, produce more words, but we can never say everything we want to in our quest for understanding the world. What Lacan’s “real” therefore suggests even more powerfully than Kant’s “thing-in-itself”, is a multidimensional, “virtual” (in the Scholastic sense of “potential”) ontological realm that is “right there”, yet inaccessible, somewhere beyond the language in terms of which we express the way we understand our world. This resonates almost audibly with the quantum universe of multiple, co-existing possibilities. Besides, unless one postulates the “real” in this way as a kind of ontological “matrix”, it is difficult to account for truly novel historical events.