My comments at other blogs—part 1


I sometimes post comments at other people’s blogs. Since a thread at these other blogs often is only partially related to the points I am interested in or am making, I don’t always have enough space to explain my points at that blog. Yet, simply in order to note something, I do infrequently post a few comments, thinking that I will return here (at this blog) and expand on those points later on. Yet, most often, what happens is that I simply forget the points once they are thus jotted down elsewhere. All in all, I have been wanting to improve on my “notes-keeping” techniques—it’s been getting messier and still messier!

While it would be ideal to provide some further explanation on the comments I thus make elsewhere, doing so would usually take enough extra effort that whenever I think of doing so, I immediately slip into that nice and comfortable and very cozy zone of… what else? procrastination.

I have, therefore, thought of a compromise solution: To provide (at least just) the links to the comments I have written elsewhere. This way, I will at least not forget the points which I need to expand on, later on. After all, this is my blog; I do take its back-up; and so, anything that I note here will stay somewhere at least in the backups (if not also in the mind); it won’t go permanently out of my mind, and therefore all lost to me.

Thus, from this post onwards, I will occasionally be lumping together a few links to my own comments elsewhere, via a post specially dedicated to such links, here.

Further, I have also decided to highlight some other interesting blogs or posts from time to time. Thus, though this blog was heavy on my own writings thus far, in future, it would also have a bit of a mix of other people’s blogs.

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My Comments on a Blog Post about Animation of Quantum Manner:

Recently, I have made a few comments at a CalTech+PhDComics blog post on animation of quantum matter. The post in question is here: [^].

Among the many comments I made there, I think my more notable comments are: this [^], this [^] and this [^]. Let me tell you why I think so.

But before that, the right time to visit that blog-post and to go through all comments—mine as well as others’—is: right now.

From this point onwards, I assume that you are familiar with both the post and all the comments it received.


The first of my comments [^], though deliberately long, basically tries to take away that “quantum” kind of an aura which invariably engulfs any mainstream QM-based explanation of any QM phenomenon. Here, Prof. John Preskill and Dr. Painter had (probably though not at all very deliberately) introduced precisely this element of a mystery, by highlighting the asymmetry part of it, without providing any clue as to why the asymmetry might be arising. As soon as I saw the video and read their answers, I thought they were going overboard in emphasizing that asymmetry part.

In laying emphasis on the fact that this was not a simple, passive mechanical oscillator but one that was being actively (nay, aggressively) being kept cooled down to the near-absolute zero temperatures, I tried to remove that usual “quantum” sort of a fog surrounding the issue.

BTW, though it’s a minor point, in my comments, I also tried to indirectly emphasize the fact that starting from a non-absolute zero K temperature, you cannot ever hope to reach 0 K. This is not an issue pertaining to an ignorable kind of a small number; it’s not a matter of a relatively insignificant experimental error; it’s a matter of an important principle—of a law of thermodynamics. You don’t begin to violate laws of thermodynamics in your presentation just in order to make the matter look sexy to some clueless American high-school students or their equivalents there or elsewhere (regardless of their age, education,  alma mater, the obtainment of a tenure or a VC funding, fellowships obtained from professional societies, instances of their otherwise competent PhD students being unethically flunked during qualifiers, etc.). You don’t do that. You don’t have to, in order to either highlight the achievements of science or even to make it attractive.

The second and third of my above-mentioned comments (i.e. this [^]  and this [^]) introduce what in that context perhaps is a novel idea. Apparently, people haven’t pursued the single-quantum versions of the experiments which study the transfer of a quantum state from light to a mechanical oscillator (or vice-versa). Perhaps, before I introduced the idea, they hadn’t even thought of doing so—not in this context. (Such things are easily possible.) In any case, they should pursue such experiments. Why?

The reason is twofold.

Firstly, these days, there seems to be a new and special streak of QM skepticism gaining some traction, esp. in the American science circles.

For instance, no sooner does a private sector Canadian company D-Wave introduce some new version of their hardware than a small army of the NSF/American public R&D-funded skeptics launch scathing attacks on all its claims. For instance, see the nature of the comments at Prof. Scott Aaronson’s blog [^]. Being extra critical of extraordinary claims is perfectly OK, nay, it is even demanded by the rigours of science. But being skeptical never is: skepticism, even an informed skepticism, is not a route to knowledge. Skepticism only destroys knowledge.

Now, coming to Prof. Aaronson, inasmuch as he does maintain that extra rigour of criticism, he is to be encouraged and applauded. In fact, when he apparently isn’t too busy (or too passionately in the thick of the thrust and parry, i.e. “debate”), Prof. Aaronson himself seems to be pretty well-balanced about the issue. (He obviously has a tilt against D-Wave, but he also, equally obviously, has absolutely no axe to grind here—that much is clear. And, when it comes to summarizing, it’s good that he forgets the more shallow among many of all those con points (sometimes his own, too!), and thereby ends up presenting a pretty well-balanced viewpoint. Not necessarily the most comprehensive picture, but still, a pretty balanced one in terms of what all it does consider, anyway (and he does cover an impressive lot of the territory.))

Yet, if you go through all of those hundreds of comments (sometimes even 600+ comments) that each of Aaronson’s posts generates, you would certainly come out getting a definite feeling that something deeper is at work here than what meets the eye at the surface. Not just a feeling, not even just an evidence of sociology, but more: you will come out also with a lot of links pointing towards hard evidence too.

It’s almost as if someone or some influential group in that giant, American government-sponsored, R&D machine has decided to throw the monkey wrench into any QC works, esp. that elsewhere, by “showing,” sometimes even via dishonestly thin argumentation, that any new results favoring scalable QC is either unbelievably unreliable or that there is nothing QM-ness about it, that the result is what should be expected on the basis of classical mechanics alone. (BTW, “government-sponsored,” or, better still, “government-controlled” is what the phrase “public science” actually translates into.)

Of course, the “public science” in America is not the only party against any of these scalable QM kind of claims (or even experiments). Dr. Roger Schlafly [^], a more or less completely independent researcher, too, has flatly denied any possibility of ever building a scalable QC. He doesn’t have any specific evidence or a principle to cite in defence of his position. Apparently, he just feels that way. Oh, BTW, Prof. Scott Aaronson (himself) has (justifiably) criticised Schlafly.

(BTW, I otherwise have a significantly good opinion of also of Schlafly’s judgment, much of it formed in reference to his book on Einstein. I haven’t read this book completely, but from whatever portion of it that I read, it seems to be a very well written, and an even better researched a book. (BTBTW, the Google Books Preview (still) allows you to read this book in its entirety. It’s just that I haven’t found the time to complete my reading. (TBD!)))

Anyway, coming back to the issue at hand: With this background, I thought that Dr. Mankei’s comments at the above-mentioned (CalTech+PhDComics) blog post came perhaps a bit too early, and perhaps they were not sufficiently thought through. (He also immediately posted an independent paper to arXiv, for this purpose!)

Secondly, in any case, what I wanted to point out and emphasize was the possibility of a way that should convincingly show the quantum nature of the mechanical oscillator in this kind of an experimental arrangement. Overall, I am happy about suggesting the single-photon version of this QM experiment.

I sincerely believe that not only is the single-photon regime interesting in its own right but that in systematically reducing the flux by some 15 orders of magnitude, we could perhaps also be covering some interesting intermediate regimes as well.

Of course, the main point still concerns the single-photons regime. If you see the red-shift even in the single-photon regime, but no blue-shift, I believe that no one will be able to come up with a very rational argument interpreting such a result in a classical mechanics framework. And, a systematic reduction of light flux should provide additional clues to the way that the quantum nature of matter emerges gradually.

It’s true that our intuitions can so easily go wrong once in the quantum realm. Yet, my own intuition is that even if not in this particular experimental set-up (i.e. with this big a beam for the mechanical oscillator) then at least in a different but similar experimental set-up, the quantum blue-red asymmetry would continue to show up even in the single-photon regime. (TBD: write a post to indicate the reason behind keeping this intuition.) It should make the critics skeptics fall silent (for a while!!).

One final note. If you wish to see more comments on this matter, see Sean Carroll’s coverage of the same experimental development (and the same PhDComics-produced video) at his blog, here: [^].

* * *

I have quite a queue of (even very recent) comments I made elsewhere. I should be back with a couple of them pretty soon. Also, a few interesting links.

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One more series! … What happened to the earlier series on tensors?:

I will resume my series on tensors once I get settled in Karjat. As of today, I am too busy organizing my stuff for the relocation to Karjat. And, I anyway don’t have a scanner at home. (Have been jobless, remember?). Friends whose scanner I could have used also all seemed to be too busy these days. So, I have decided to postpone the tensor-related series for a month or so. I will do the experiment myself and resume the tensors-related series in or after mid-July.

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Update (June 23, 2013, 11:38 PM)

A Song I Like:
(Marathi) “ghar thakalele sanyaasi, haLu haLU bhint hee khachate…”
Music and Singer: Hridaynath Mangeshkar
Lyrics: Poet “Grace”, i.e., (Marathi) MaNikrao GoDghaaTe


[As usual, may be I will come back and edit this post a bit—or, may be, I will not!]

[Update June 23, 2013: Added: The “A Song I Like” section. May be, I will come back and edit and streamline this post, once, again!! OR, May be, I will NOT!!!]]



So, it is a QC (at least this week!)

I wanted to write on tensors etc., but a few very fresh inputs concerning the D-Wave device have appeared, all barely within the past 24 hours or less.

First, it was Prof. David Poulin commenting at Prof. Scott Aaronson’s blog once again [^], alerting some new work from Prof. Troyer. Unlike in his last comment (on the same post, when he thought that it was not a QC), Poulin has now come closer towards (or has started) supporting the position that the D-Wave device is a QC:

“…the problem instances that are easy for the D-wave device can sometimes be hard for the SS model. This is interesting new evidence supporting the quantum nature of the D-wave device.”

Next, a very valuable comment by one Bill Kaminsky appeared on Aaronson’s blog, very neatly explaining the Smolin and Smith model [^], and then contrasting it with the new result by Troyer. [Guess this Bill Kaminsky is the same as one William Kaminsky, who, in turn, is a PhD student in QIS at MIT. (… Just a Google search, that’s all!)] … Incidentally, more explanatory material concerning the adiabatic quantum optimization, quantum annealing, and classical annealing, written by Kaminsky, had already been put up last week at Henning Dekant’s blog; see here [^].

Finally, while idly thinking about all these things, even as idly browsing Prof. Poulin’s home page, I just idly happened to hit the “New on quant-ph” link [^] at its bottom, and thereby landed at the arXiv site; and once there, I noticed a new paper by Troyer (and (eight!) pals): [^].

Essentially, what Troyer et al. now say is that the D-Wave device does something that the classical devices apparently don’t, and so, the D-Wave device must be quantum! … If not all the classical devices, then at least the two devices: one, considered by they themselves, and the other, considered by Smolin and Smith. The D-Wave device behaves unlike both.

Further, Troyer et al. offer the following conjecture to account for the difference between the D-Wave chip and the [semi-]classical models:

“…The question of why SQA and semi-classical spin models correlate so differently with the D-Wave device is obviously important and interesting. We note that while SQA captures decoherence in the instantaneous energy eigenbasis of the system, so that each energy eigenstate—in particular the ground state—is itself a coherent superposition of computational basis states, semi-classical spin models assume that each qubit decoheres locally, thus removing all coherence from the ground state. We conjecture that the fact that the D-Wave machine succeeds with high probability on certain instances which the semi-classical models finds hard, can be understood in terms of this difference.”

[emphasis mine]

So, looks like, it is a quantum computer, after all. … At least, for this week!

* * *

Clearly, more studies required. So, here are a few questions to the QC research community:

What needs to be done to study the above conjecture more closely? Would some simple and special-purpose simulations that directly allow for a parametric control of the degrees of decoherence, help at least to illustrate (if not to fully support) the above conjecture? Such simulations could be highly simplified (say involving just a linear graph) but, still, sufficiently complete so as to be able to isolate, study, and possibly help settle, this issue.

How do you square off the quantum-ness of the D-Wave chip, and the “absence” of a speed-up, as discussed on Aaronson’s blog?

What measures would you suggest to capture the “percentage quantum-ness” of a QC? of an adiabatic quantum device such as D-Wave’s?

On these measures, how quantum are the current two D-Wave chips (D-Wave One and Two)? What is your estimate?

* * *

May be, more, later. (Who knows, it might once again collapse back to being a simple classical computer, next Monday!)


[May be I will come back (right today) and edit this post a bit, so as to make the write-up a bit more streamlined.]




Is it a QC?

This post began its life as a supposedly brief update to my earlier post [^] on D-Wave’s paper, but the text soon grew long enough to become a separate post by itself. So, here we go.

Predictably, a controversy concerning the D-Wave paper (and its coverage in the media) came up soon later, at Prof. Scott Aaronson’s blog [^]. At 300+ comments (as of publishing this post), there is a lot of speculation, skepticism, and hilarity of the usenet/slashdot kind going on over there, apart from also some commentary.

However, as far as I am concerned, the most interesting part in (re) examining the paper and the related claims, was the following doubt which the controversy helped highlight: whether this particular D-Wave device had actually succeeded in exploiting, at least in part, the specifically quantum-mechanical effects, or not; whether there was an engineering success in controlling, at least in part (and to a practically significant extent), the quantum decoherence effects, or not.

The controversy was not entirely unexpected; recall this bit from the first New York Times story [^]:

““There is no sense in which this is the definitive statement about quantum computing,” Ms. McGeoch said. “I’m more interested in how well it works, not whether or not it is quantum.””

Though they called it a “quantum computer” (and I repeated the term), the term obviously was being used in a somewhat loose sense.

And, yes, I will admit it: without going through the paper well, I rather relied on the peer-review process, and so certainly thought, at least at the time of writing my earlier post, that D-Wave had a more impeccable and comprehensive result than what now seems to be the case.

But returning to who is interested in what: Well, as far as I am concerned, the issue of whether they got any speed-up or not, is strictly secondary—it’s “just” a consequence!

(In fact, I even don’t care if a QC research group cannot factor any composite beyond some single digit number, as of today. So long as they demonstrate a practically significant control of decoherence, and some clue about how they expect to scale it up, even their success in factoring only a small number would still make sense to me. Any future value of a QC in cracking open secret codes, or in designing better drugs through quantum chemical modeling, would be “just” a consequence, as far as I am concerned.)

To my mind, the real issue is: whether D-Wave succeeded in building a quantum computer (with some promise of some significant levels of a future scalability), or not.

So, from this angle, the most significant comment at Aaronson’s blog has been this one [^] by Prof. David Poulin, alerting the appearance of a paper by John Smolin and Graeme Smith, both of IBM, at arXiv, yesterday [^]. In case you are wondering whether to give this paper a read or not, let me remind you that IBM is a (corporate-sector) competitor to D-Wave. And, if that isn’t going to help, let me quote a bit from the main text of the paper:

“Since classical simulated annealing is intrinsically random and ‘quantum annealing’ is not…”

[emphasis mine]

and a line from their conclusions section:

“The deterministic nature of quantum annealing leads to rather different behaviors than the random processes of simulated annealing.”

[emphasis mine]

Interesting, no? (LOL!)

Of course, my own interests are in the foundations of QM, in providing a proper conceptual explanation for (and even mathematical expression to) the specifically quantum-mechanical effects/paradoxes/oddities, and not in the details of this or that quantum-mechanical process, whether it has some/a lot of/very great merit in building a scalable QC, or not.

So, I am not going to look too closely into this IBM paper either. Or provide a commentary on the position(s) it takes, its merits, or any polemical value it provides in this controversy (or in any other!). Or, add in any other way, to this D-Wave-related  controversy. … That way, I am not totally averse to controversies, but as far as this one goes, I find that it is a greater fun taking a ring-side view, here.

For another thing, these days, I am also thinking of quite different (and between them, somewhat unrelated) things: diffusion, small dams and water resources engineering/management, and tensors. Expect a post or two on these topics, soon enough.

So, all in all, even if I am having fun watching this controversy develop and grow, I guess I am going to sign off blogging about it. I won’t write any further on this topic, unless, of course something even more funny (or definitive, even if a bit serious) emerges from it.


The QC pulls ahead of the CC

The first peer-reviewed paper to demonstrate that a quantum computer (QC) outperforms a conventional computer (CC), is here (PDF) [^]. [HT to Henning Dekant [^]].

The New York Times’ story is here [^].

Oh, BTW, this is one of those rare occasions when a peer-reviewed PDF of a scientific paper is being made available from a newspaper’s commercial servers—not from a server at some government-run Important National Lab, or a taxpayer-funded Wonderful State University, or for that matter, even arXiv! An interesting bit by itself, don’t you think?

(And, BBTW, I am old enough that as soon as I read this news, I instinctively slipped into wondering as to the time when the Russians might come forward with some “evidence” to show that they had accomplished the same thing some a few years earlier. … I guess I should go and enquire with the folks at the JNU New Delhi, ISI Kolkata, or IIT Bombay—they should know.)

Anyway, coming back to this exciting bit of news itself: at least at the time of going to wordpress, far too many American blogs on quantum computing still were completely silent. Especially those being maintained by the American academics. Several days over, and still not even a cursory acknowledgment!

Yet, this bit of news is not a hype; the advancement is for real.  Check out the following links (many of which were mentioned in Henning’s post, anyway): New Scientist [^], MIT’s Technology Review [^], IEEE [^], and even Nature [^].

So, an exciting news item, this one surely is. But what is comprehensively missing is one thing: that American (Hindi word) “taDkaa.”

The MIT Technology Review story, for instance, has this as the subtitle of its online story:

“Tests suggest that a CIA-backed quantum computing technology can be very powerful for some kinds of problems.”

Very careful.

“A” quantum computing technology—not the first to get a definite practical success.  “CIA-backed”—which means, this hint: the CIA has the money to pour into some potentially wasteful projects, and also have the means to choke out any adverse news reports if they fail, unlike the real innovative, open, democratic institutions like certain US universities. And, only “some” kind of problems would become solvable—it’s certain that with more research at MIT and Berkeley, the hardware is bound to get intelligent, but don’t expect it to be omniscient, that’s all. (Parenthetically: the company is Canadian.)

Sooooooo careful.

So, all in all, what I am missing out on is that American “taDkaa.” Even if Lockheed Martin, an American firm, already has gone ahead with the plans to use it [^], and an American by name Bo Ewald has become involved with the DWave [^]. [Full disclosure: I worked with e-Stamp roughly around the same time that Bo Ewald did. [Hi Bo!]]

The major reason I want to see some real American “masaalaa” and “taDkaa” on and around this topic, and if not that, then at least some ordinary hype on it, is: so that people get mysterious about this whole thing. Remember, the field of quantum computing carries two highfalutin words: “quantum” and “computing.” Even if the second word has lost a bit of a shine (Steve Jobs is no longer around, Chairman Bill is no longer the Chairman, and even the DC threatens Google only once in a while—there is no real DoJ action), it still carries a lot of aura. And, till date, they have managed to keep the first word, neatly wrapped up in a thick, impenetrable kind of an aura of a mystery.

When you combine the two together, there should be a multiplicative/exponential kind of a synergy. “Quantum Computing,” you know, should sound big. BIG. VERY BIG.

It, then, would be such a fun to step in on to the scene, and begin explaining how quantum computing is such a simple thing, after all! … How it is not all that big a mystery; how it really works. Explaining quantum computing on the basis of [clears the throat] my novel approach, would be fun, provided there is a preceding American “taDkaa” to it. In sufficient quantities. Together with “masaalaa.” To make it all mysterious in the first place.

There is no fun carrying just a pin around, no matter how sharp it may be. It’s no fun if you do have the pin, but there is no balloon in the first place—or, as in this case, there is that balloon, but still, no one is willing to inflate it.

* * *

Congratulations to the engineers and physicists at the D-Wave, anyway!