The year 2013 started turbulent for the quantum computing field with a valiant effort by long time skeptic and distinguished experimentalist Michel I. Dyakonov to relegate it to the status of a pathological science akin to cold fusion (he does not use the term in his paper but later stated: “The terms ‘failed, pathological’ are not mine, but the general sense is correct.”).
Scott Aaranson took on this paper in his unique style (it’s a long read but well worth it). There really isn’t much to add to his arguments, but there is another angle that intrigues my inner “armchair psychologist”: What exactly is it about this field that so provokes some physicists? Is it that …
- … Computer Scientists of all people are committing Quantum Mechanics?
- … these pesky IT nerds have the audacity to actually take the axioms of Quantum Mechanics so seriously as to regard them as a resource for computational engineering?
- … this rabble band of academics are breeding papers at a rabbit’s pace, so that no one can possibly keep up and read them all?
- … quantum information science turned the ERP paradox on its head and transformed it into something potentially very useful?
- … this novel science sucks up all sorts of grant money?
The answer is probably all of the above, to some extent. But this still doesn’t feel quite right. It seems to me the animosity goes deeper. Fortunately, Kingsley Jones (whom I greatly admire) blogged about similar sentiments, but he is much more clear eyed on what is causing them.
It seems to me that the crux of this discomfort stems from the fact that many physicists have a long harbored discomfort with Quantum Mechanic’s intractabilities, which were plastered over with the Copenhagen Interpretation (which caused all sorts of unintended side effects). It’s really a misnomer, it should have been called the ostrich interpretation, as its mantra was to ignore the inconstancies and to just shut-up and calculate. It is the distinct merit of Quantum Information science to have dragged this skeleton out of the closet and made it dance.
The quantum information scientists are agnostic on the various interpretations, and even joke about it. Obviously, if you believe there is a truth to be found, there can be only one, but you first need to acknowledge the cognitive dissonance if there’s to be any chance of making progress on this front. (My favorite QM interpretation has been suggested by Ulrich Mohrhoff, and I have yet to find the inspiration to blog about this in an manner that does it justice – ironically, where he thinks of it as an endpoint, I regard it as allowing for a fresh start).
Meanwhile, in the here and now, the first commercial quantum computing device the D‑Wave One has to overcome its own challenges (or being relegated to a computing curiosity akin to analog neural VLSI). 2013 will be the year to prove its merits in comparison to conventional hardware. I’ve been in touch with a distinguished academic in the field (not Scott A.) who is convinced that optimization on a single conventional CPU will always outperform the D-Wave machines – even on the next generation chip. So I proposed a bet, albeit not a monetary one: I will gladly ship a gallon of Maple sirup to him if he is proven right and our dark horse Canadian trail blazer don’t make the finish line. The results should be unambiguous and will be based on published research, but just in case, if there should be any disagreement we will settle on Scott Aaronson as a mutually acceptable arbiter. Scott is blissfully unaware of this, but as he is also the betting kind (the really big ones), I hope he’d be so kind as to help us sort this out if need be. After all, I figure, he will be following the D-Wave performance tests and at that time will already have formed an informed opinion on the matter.
The year 2013 started off with plenty of QIS drama and may very well turn out to be the crucial one to determine whether the field has crossed the rubicon. It’s going to be a fun one.
Henning,
when you find the inspiration to blog about my interpretation of quantum mechanics, consider explaining why you think that I think of it as an endpoint. As far as my textbook is concerned, I think of it rather as an attempt to purge the theory’s formalism of misleading metaphysical accretions. To be sure, I have my own ideas about its ontological implications, which open avenues I have only begun to explore. And to be equally sure, they are totally irrelevant to the future of QM-based technology, which began long ago with lasers and semiconductors. By “a fresh start” you mean the (technological) war against decoherence?
– Ulrich
Ulrich, maybe I misread some of the philosophical implications that you expressed. Certainly will have to explain in more detail what I read into it (part of the due diligence required to do it justice).
In mischievous fashion, I continue to think that Quantum Computing is a salve and a distraction from facing up to the very real problems in fundamental physics.
After all this work, folks can factor the number 15!
Would it not be more interesting to fix the broken theory called QM?
@Kingsley:
Depends. Individuals differ in what they find interesting.
But you are right. The mainstream theory is broken, and, sure, an advancement in technology cannot by itself help fix it, only an advancement in theory can. The invention of the IC engine, e.g., couldn’t have by itself “written” or “engraved,” using some supernatural means, the second law of thermodynamics into people’s minds.
At the same time, attempts to build QCs are obviously going to “throw up” (i.e. help us spot or isolate) a lot of detailed areas of further research. This expectation would have held even if the QM theory were not to be broken in the first place.
For an analogy: In materials science and engineering, classical theories are a norm, and though this ruling paradigm never quite posed fundamental issues or riddles as in QM, the finer investigations of materials, first at the microstructural level and then at the atomic level, have helped lead not only to better alloys and composite materials but also to transistors, chips, and conventional computers!
Similarly, we may expect potential advancements in many areas simply in trying to build a QC—even if a single overarching physical principle showing how scalable QCs are impossible (the case that Scott often highlights) is never experimentally discovered (or gets theoretically formulated) in that process.
The QC project (as nanotech) does seem as if it is a rich vein for progress based on QM.
–Ajit
[E&OE]
Ajit, I also strongly sympathize with Kingsley’s stance on the matter but also hope that via the route of QC some of these issues may be flushed out as it puts the focus on better understanding and controlling decoherence. I.e. my optimistic expectation is that QC will after all be a net benefit, in the sense that more CS researchers will think about QM rather than physicists about complexity theory (although if the latter are string theorists I am all for it).
Ironically, I am great fan of Ulrich Mohrhoff as well as Kingsley Jones work. Yet, the former wrote a book on why QM makes perfect sense, why the latter thinks QM is broken. Nevertheless it seems to me they are a perfect match, as Ulrich presented the most lucid and rational interpretation of QM while Kingsley came across an intriguing mathematical framework that to me seems to be key to a proper understanding of the correspondence principle.
So much to think and blog about and so little time 🙂
Hi Henning,
Yep. So little time and so much to read and to think (and to blog!) about… But, anyway, just recently I had run into your Amazon.com review of Mohrhoff’s book, and had thereafter decided to line it up for reading—though it will be quite some time before I come to it, I guess. (The to-be-read stack is already a mile high or so, and so is the to-be-implemented-in-C++ stack, to-write stack, etc.)
In the meanwhile, I would like to repeat my request (and sometimes an offer) to any one putting forth a new view/theory that addresses the well known riddles of QM: could he please supply a C++ program for the simulation of a simple enough but specifically quantum-mechanical phenomenon, e.g. the single-quantum double-slit interference experiment? if not, could he please put it in a form that allows someone (say a beginning graduate student of a computational science and engineering program) to straight-forwardly translate the description into a working program? (Modeling conveniences like the use of a pseudo-random number generator in place of a “true” random generator (whatever it means), etc., are assumed.)
So, there.
BTW, I liked your analysis of why QC might provoke mainstream physicists…
Bye for now.
–Ajit
[E&OE]