Misplaced Pages

It's my understanding that San Marco 1 used U.S. launch vehicle, the Scout. See http://www.univ-perp.fr/fuseurop/sanma_e.htm If you have different information, please let me know.--agr 16:55, 25 September 2005 (UTC)

Fitzmas

Thanks for noting the CNET story in the debate about deleting Fitzmas. It's a valuable addition to the discussion, as a good indication that the article should be kept. I've also added a reference to it on Misplaced Pages:Misplaced Pages as a press source 2005. There's a similar entry in the September 21-30 section -- a London Times article that cites a person's Misplaced Pages article as evidence of his importance. JamesMLane 10:46, 30 October 2005 (UTC)

Glad to be of help. --agr 14:37, 30 October 2005 (UTC)

causality and QM

Hi,

I checked out your own site. Interesting. You've been doing computer stuff forever, compared to me. I built an EZ-80 around when the Z-80 first came out, (wire wrap on perf board), and later put together a couple of "Big Board" computers (later to become the first Xerox 820s (I have the circuit boards to prove it), Kaypros, and DEC Robins). But anyway I'm writing because of the comments you put up on the causality article. I agree with what you said. But Ingham, the person who inserted that stuff, is a bright guy who reminds me of lots of my physics major cohorts who were inarticulate when you took calculus out of the picture. I suspect that he may actually have something to say, and if that is the case it should not be lost because some editors of Misplaced Pages are impatient and zap out anything that seems questionable to them. On the other hand I have spent 20-30 fruitless hours trying to get a separate line on what he is talking about. Others tell me it is vanilla QM stuff, but if that is the case he has even more of a problem communicating than I had recognized. I put a link to the "diff" that gives his original article after your remarks on the discussion page for the causality article. If you have time, please take a look at it and see whether it might have some "coded" sense to it. I don't like to see new contributors chewed to pieces, but that is what has happened in the last few days in response to the request for deletion that was put against his article.

Thanks. P0M 03:34, 5 November 2005 (UTC)

I've responded at Talk:Determinism#Determinism and QM --agr 17:06, 6 November 2005 (UTC)

And thanks again, for making about first substantive contribution I can remember. Unfortunately it may be that Ingham has gotten so frustrated that he has stopped communicating. Please ignore the following if it doesn't pique your interest. I've wasted far too much time on it already.

Here is the central point of his article, back before I started mucking around with it -- together with my comments of today:

In the measurement process, new particles, such as light are brought in to perform the measurement. If, at first, these measuring particles are described quantum mechanically, the description remains deterministic and no probabilities arise. However to get the information into a notebook or (non-quantum) computer, it must be brought to the human scale where maintaining phase coherence is impossible.

This language seems subject to many different interpretations. He may have something in mind like the Heisenberg's_microscope thought experiment. If so, he is saying that a gamma-ray photon and an electron and a microscope with a piece of unexposed photographic film at the place where the image is focused are all in a closed box, that one has "quantum mechanically described" them, and that when the photon hits the electron and bounces to where it shows up on the film then everything is perfectly "deterministic, and no probabilities arise." (Carrying this idea back to the article on causality where this stuff all got started, that would presumably mean that what happens when one bounces a gamma ray off an electron is all deterministically causal, no dice throwing God involved.) But the experimenter has "the information", presumably because s/he had the original "quantum mechanically described" data and can calculate from there. Now it sounds like he is saying that the next step is that this known data must be "brought up to the human scale" -- which is going to sound to the average well-informed reader as though the experimenter does something to the "mystical data" (my mystified attempt to describe it) to make it understandable by non-physicist or non-mystic readers. He gives a clue to what he is probably really talking about by mentioning the loss of phase coherence, but I've never been able to get him to clarify this passage. I think that means that he believes that physicists (and maybe physicians) can understand it and that the average reader can be properly ignored, but I'm probably being cynical, which is why I've resisted saying any of this so directly before.

Because the classical approximation does not conform to the uncertainty principle, it contains information that the quantum system, which does conform, cannot supply. This non-physical information is generated randomly.

To me this sounds like either of two things that we talked about freely as undergraduates trying to get the answers in the back of the book: (1) waving the magic wand, or (2) supplying the fudge factor. The classical approximation (to what? to the real answer?) contains information. But it must really contain "information" that doesn't exist because it has to be created by a random number generator of some kind. It's almost as though he thinks the experimenter has replaced Einstein's dice-throwing God.

If classical physics were an adequate model for this situation, one would fire gamma ray photons in fairly rapid sequence that would hopefully light up any electron that happened to drift into the microscope's field of view, occasionally that would happen, and one could track the electron as it drifted across the microscope's field of view, judging its x and y coordinates by successive black spots on the developed negative, and perhaps even getting the z coordinates by some sort of auto-focus device on the microscope that would keep a log of how it racked the microscope in and out. To me, the photo-chemical reactions that occur in the photographic film count as physical events and as providing information about the real world, but I am not sure what Ingham would say. In the classical version I would not say that these spots are "generated randomly." I wonder if Ingham thinks they are "generated randomly" under a correct QM description. But I am grasping at straws.

In addition phase information in the quantum description cannot be represented classically, and is lost.

I guess I am a helpless literalist, but to me this statement fits in the general category of the magician who says, "Now you see it, now you don't." I think Ingham is anthropomorphizing terribly. I imagine that he is trying to express something entirely different, but what he says I must interpret as there being "phase information" sitting there in the quantum description of the experiment that he has thusfar not even really described, and then for the benefit of poor mortals somebody come along and puts it into classical terms. (Like what, x, y, z, t...?) Then having done that the phase information is dumped into some quantum waste dump somewhere in the void.

One of Messiah's examples is measuring the position of an electron with light. If the light's wave function is not know and included in the system wave function, the predictions are of probabilities, because the light photons exchange unknown amounts of momentum with the electron.

I think I found Messiah's description of Heisenberg's microscope, I, 143, and it is perfectly straightforward and comprehensible, even to me. It has nothing to do with the mystification in Ingham's account.

I am wondering if I am missing something in the above quotation. How much is he assuming is not known about the photon? Its frequency? Its direction of travel from source to electron? Conceivably one could calculate an impact for a gamma photon on a straight-line course and actually have a bank shot by an ultraviolet photon. I think that if so little were certain I would call any calculation a guess not a probabilistic prediction.

Anyway, if the contrary were the case, if the photon's wave function were known, would that make the predictions not probabilistic? To me he appears to be saying that if one knew enough about the photon, the electron, and the rest of the apparatus, then one could predict in a non-probabilistic way where the photons would show up on the detection screen (photographic film). He sounds more like Bohm than Messiah to me.

So, it is the requirement for extra information, beyond what is specified by the uncertainty principle, in a classical description that is responsible for the probabilities.

It could be that all he is saying is that if Δx * Δp >|= h, then when we state a value for x or for p we have to say something like x±d or p±d'. But I don't think so.

From this point of view, this information does not describe reality.

I suppose it is perfectly obvious to Ingham what "this information" is supposed to refer to. Whatever it is, is he saying that empirical observations of the form "In this run of the one at a time electrons through a double slit experiment, hits were recorded at p1,p2,....pn" do not describe reality? According to my limited command of the English language, it would seem so.

The experimenter is simply "asking more from one poor little electron than it has".

i.e., "An electron does not have a position and we insist on giving it a position"?

A Cal Tech grad student, or maybe it was U Cal Berkeley, told me his stuff all makes perfect sense, so hopefully it is my English that is at fault -- or maybe not. P0M 18:23, 6 November 2005 (UTC)

Just to be clear -- the real question is how, if Ingham has a point and knows what he is talking about, should what he is trying to say be put into words that a bright high school student can understand? (It doesn't have to be comprehensible to me, just to the average well-informed reader.) P0M 18:34, 6 November 2005 (UTC)

I think the short answer to your question is that we have to rely on the Misplaced Pages process. If someone has a clearer explanation, it can go in one of the articles on QM. If other editors don't think the explanation is superior, it will be edited out. Note what it says at the bottom of the edit page: "If you don't want your writing to be edited and redistributed by others, do not submit it." If Mr. Ingham is discouraged by this, there are other places to publish his views. For example, I have a screed on Bell's inequality on my home page that I probably would not submit to Misplaced Pages. --agr 19:01, 7 November 2005 (UTC)

Jerome H. Lemelson

Thanks for your last edit in this article! --Edcolins 20:51, 17 November 2005 (UTC)

Category:cryptography

Category:cryptography is getting too big. I'd suggest a project to move articles to sub categories where possible and maybe add some categories as necessary. Perhaps trim the text on the category page too.--agr 18:34, 2 December 2005 (UTC)

I agree it needs sorting out. The thing that puts me off is that you can't edit categories directly; you have to change tags on each individual article, which makes it cumbersome to maintain. Maybe there are bots which can help? — Matt Crypto 11:28, 3 December 2005 (UTC)

MacBook Pro

I just checked out your recent edit to MacBook Pro. You state that the DVD burner is dual-layer read but only single-layer write. I have no firm evidence one way or another but it was my impression that the drive is actually a dual-layer writer. Are you sure that it is actually only single-layer? --Yamla 22:48, 12 January 2006 (UTC)

Yes, for now. I just talked to Apple at MacWorld. See my comments in the discussion page.--agr 22:51, 12 January 2006 (UTC)

Thanks. Very interesting and a little surprising. Maybe I'll sit out this round and pick up the next round when they've brought back some of the features. Oh, who am I kidding? If I had the money now, my order would already be in. I've never had the need for dual layer, not with the media as expensive as it currently is.  :) --Yamla 22:56, 12 January 2006 (UTC)

I got the sense that they accepted these limitations for now to get the product out for a MacWorld announcement. They way one Apple person put it to me was that that the MacBook specs "do not commit" to the ability to write dual layer. Another said these are "first generation drives".--agr 14:57, 13 January 2006 (UTC)

Re: Classified information

Thank you. I've responded at talk:classified information. — Instantnood 23:53, 14 January 2006 (UTC)