Thursday 13 November 2008

MG's BIG mouth, fuzzy little balls and a strange theory of light and matter

I had an email from MG a couple of days ago. "Hi Penguin, someone's floundering in QED, I said we might help them (and maybe some others) out. You up for a bit of oversimplification to get Dick's message across?"

Thanks, Malcolm Goodson, all round 'nice guy' (some say :) and only too willing to impress his idiot of an ego on an unsuspecting planet. Sometimes I think he 'jests' on purpose when he supposes that he was Attilla the Hun in a previous life! I can just imagine the pasty faced dwarf galloping across the plains on his little mongolian pony! Well what can you do? So I said yes.

Therefore, anyone who reads this blog with a desire for insightful analysis, charm and wit in equal proportions, a slightly different take on the world or just an amusing read might be well advised to steer clear of any blog which is titled 'QED + anything else'. On the other hand, those posts might give you a modest insight into the most bizarre ideas ever and cause you to question whether there is any objective reality out there so....................................

Here they are, the combined ramblings of two diseased minds working in concert but trying, faithfully, to render the great Richard Feynman's ideas in language that everyone can understand. We do not, in any way, think that we are telling 'the truth' here. It can only be an interpretation . (We do this to cover our ar**s.) We do not have the maths! BUT we believe we have it right and hope that it enlightens!

A small digression. Dick 'shared' his Nobel prize with two others but, crucially, only Dick's 'solution' is ever used. All hail to the mighty Dick :)

So, Quantum Electrodynamics, the interaction of light with matter. But first a small history lesson

By 1900 the atomic theory of matter was well advanced. A point like nucleus with electrons in orbit around, a microscopic planetary system. This was borne out by experiment, notably Rutherford's. He aimed beams of 'particles' at solids and noticed they were scattered but not as much as he expected if the atoms inside were solid ball-like objects. It seemed like there was a lot of 'space' in between the atoms which a planetary model could explain. However Newtonian mechanics, which did explain planetary motion, did not explain certain behaviour of the 'planetary' electrons.

In the very early days of the 20th century, Max Planck, solved the issue of black body radiation by proposing that electrons could only lose or gain energy in discrete amounts, 'quanta'. They were prevented from accumulating or shedding energy in a progressive way, ie by adding loss or gain cumulatively. It was all or nothing. In this way, Planck prevented the electron from spiralling into the nucleus of the atom, it could only go so far inwards since it couldn't shed 'half a quantum'.

In 1905, Albert (that's Einstein for any of the educationally challanged out there, not Roux) demonstrated that it was also possible to explain why electrons are emitted from, say, a metal when you shine a light on it, the photoelectric effect, by positing that light was not a 'wave' but discrete particles.
Only when the light particles have sufficient energy could the electron acquire enough energy to break free from the nucleus by absorbing a light particle, a photon. It didn't matter how much light (how many photons) you shone on the object, the only thing that mattered was the frequency of the 'light wave', the energy of the photons. Below a certain photon energy level (wavelength) no effect was observed. Each photon had insufficient energy to allow the electron to absorb enough to break free, no mattter how 'bright' the light, or better, no matter how many photons. He got a Nobel prize for that! The godfather of quantum mechanics who denied his own godson to the end!

By 1926, Heisenberg, Schroedinger, Bohr, De Broglie, Planck et al had got a basic theory together and thus was born 'the collapse of the (Schroedinger's) wave function', the 'uncertaintity principle', 'wave/particle duality' and an inherant 'fuzziness' to the entire universe.

However quantum mechanics had hit its first major obstacle. If you tried to predict the outcome of an experiment to match actual results using quantum theory, you could do so at a 'coarse grained' level, an approximation, but as you tried to fine tune your calculations and bring them closer to the 'measured outcome' by graining more finely, a remarkable thing happened. Suddenly, infinity entered the equations! It was as though nature had no intention of letting you see what was really going on!

In 1931, Paul Dirac postulated a 'magnetic moment' for the 'perfect', non interacting, electron of 1.0. A magnetic moment of an electron is a bit like imagining the electron as a little magnet, how magnetic is it? This was broadly in line with Maxwell where electricity, which is no more than a stream of electrons, is essentially the reverse side of the coin of magnetism. They are interlinked. One always induces the other. Experiment put this 'moment' value at 1.00118. Now it was known (from Einstein above) that electrons interacted with light, photons; so this has to be factored in and then this would then bring the theoretical more in line with experiment, wouldn't it? It must, after all, only be a minor adjustment, the difference is so small. Unfortunately, any adjustments just led to infinities again! Quantum mechanics had come to an impasse with nature. The theory on the surface looked sound but if you delved 'deeper', it all fell apart, there were these 'stupid' infinities that just would not go away! God was always closing the curtains!

It was not until 1948 that first Julian Schwinger (and independently, Tomonaga), then Feynman showed that there was a way out of the morass of infinities. It is interesting that Feynman in his lectures gives precedence to Schwinger (he was the first) but omits to say that Schwinger's methods are not used nor are Tomonaga's and also omits to say that only his are! This penguin, at least, wishes that he had had the opportunity to meet Mr Feynman. We could have played some serious bongos together!

So, where are we? Light is made of particles, photons. Electrons can 'capture' a photon and take its energy to increase its own and we have equations that work at a coarse-grain level but not fine grain. We have a theory that explains things classical physics explains and things that classical physics does not explain so we ought to be on the right track. All we have to do is get rid of those bl**dy infinities!

In the next QED blog we'll be looking at the partial reflection of light from glass and why it cycles through 0-16% reflection depending on the thickness of the glass.

23 comments:

  1. As much as I begged pleaded and otherwise cajoled thee to present this matter, I was never more relieved than to see that thou truly livest and was not consumed by some mythological germ-beast lurking under your covers when you returned a fortnight ago.

    I cannot read this now, but will return later. To ponder, hopefully with some form of comfort food- it is wet, cold and rainy here. A recipe for certain mania.

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  2. I printed it out, and read it. Now need to formulate my questions. I think I am going to consult Dick first, so I can compile several at once.

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  3. What, you don't trust me :( I die, best, ay?

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  4. I don't trust anyone until I trust myself. Don't know when that will be.

    More later

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  5. In the meanwhile here is a link for you to ponder, and if possible, expound upon how it relates to what you have written.

    The American

    :)

    http://www.newscientist.com/article/mg20026821.200-is-earth-at-the-heart-of-a-giant-cosmic-void.html?DCMP=OTC-rss&nsref=physics-math

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  6. It's funny, that article sums up why I don't read New Scientist any more. Essentially the whole article hangs on "It is thought that type 1a supernovas have the same luminosity" And yet there is not a scrap of supporting evidence in the article. That is sloppy and crap journalism! But then I don't have much time for the 'union bashing' IPC Media anyway!

    Interesting how the file name starts 'mg....' :)

    It's hard to take articles like that seriously when they start off so fundamentally flawed. What happens to all of the speculation when, in fact, all type 1a supernovas don't have the same luminosity?

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  7. Okay, I actually understood everything. You explained it well. Moving on....:)

    Thank you for your comments. I would have missed that point entirely. It was certainly entertaining, but I'm looking for facts, so.... Moving on....:)

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  8. BTW-

    I was taking the "American Scientist" for a little while, and found the writing to be quite unscholarly, though admittedly, they brought up an interesting array of topics. The New Yorker (recently bashed by the "expert journalist" in my life) seemed more scholarly, less subjective scientific topics than either of these two journals.

    I caught some typos in the New Science article I read yesterday. It's not a good sign.

    Would you mind suggesting a journal that is more critical?

    What do you think of National Geographic?

    Also, who funds the National Science Foundation? (or do you have a different one over in the UK? If so, what is the name?)

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  9. 'Nature' and 'Scientific American' are the closest to a 'half way house' but these are wide ranging and not limited to a single discipline. They can also be too 'scientific' because their articles are often peer reviewed, not just something slapped together by some itinerant journalist. However they are expensive for casual reading.

    I used to get 'Nature' across my desk when I worked for the Medical Research Council but...(Should now say thank you properly to Shereen for all those Bob Bakker articles from the seventies on 'warm blooded dinosaurs' you dug out for me; and John Ostrom articles too tho' I never asked! It's nice to know I was ahead of the game, even then. Where are you now, Feduccia?:)

    The UK has a 'network' of Govt funded 'Research Councils', quasi government departments similar to the NSF and NIH, the funding comes from central Government but they notionally have autonomy about how the money is spent. They are intended to promote research in medical, physical, engineering and social sciences, both in their own establishments and in universities.

    Strange, thinking back, how easy it was to bump into a Nobel Prize winner; Max Perutz, Sidney Brenner (and his motorbike), Peter Medawar, Cesar Milstein, Francis Crick and that rare beast indeed, a 'double laureate', Fred Sanger. Oh and more 'Knights of the Realm' than you could count. Also responsible for the only times I ever got into 'print', 'thanks to....' usually for digging in archives :)

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  10. :) At least you are mentioned. So, what is your degree?

    What, exactly do you do now? (Other than hi-jack a penguin's blog)

    Always curious who it is I am speaking with, what they do, and how they got there. Sort of a meta- PHYSICAL study in the end justifying(or not) the means.

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  11. Okay, questions:

    What are: Nonlinear Dynamics
    Eigenvectors
    Eigenvalues

    Also, what do you know about The Imperial College of London, as far as recent research trends/ successes?

    Thanks!

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  12. Languages.

    I went from archivist to managing records, usually of people, and fell into IT in a part-time sort of way about twenty years ago. Now, full time, I do a little coding, a little database administration, a little network support, communications, some software support and lots of banging my head against the desk when Windoze does something it's not supposed to :)

    Scarcely the most exciting job in the world but it pays the mortgage, keeps me in the occasional bottle of Krug and it's nice on occasion to confound people's expectations of what someone in IT is supposed to be like :) Burger/pizza guzzling geek I am not :)

    Work should actually be fun for a change on Monday. I shaved my beard off for the first time in nine years today! It's taken ten years off me, I only look a pasty faced 14 now :) They probably won't let me in the door, unrecognisable! I'll probably regret it tomorrow. That and the fact that the robin now has to look for another home :)

    Non-linear dynamics? The opposite of linear dynamics :) Seriously, most science is founded on linear dynamics because the equations are soluble with a pen and a piece of paper. Even quantum mechanics is linear. Non linear dynamics, flowing liquid, turbulence, weather etc are much harder, almost impossible, to model mathmatically because initial conditions and later perturbations can affect the behaviour of the system in predictable but very hard to calculate ways, the so-called 'butterfly effect' of chaos theory. Computers do however now make the maths a little easier. It is to say the least very much about the maths!

    Eigenstate: one of the possible states of a quantum system. It is also very much in the maths. If you apply an 'operator' to a wave equation and that wave equation remains essentially the same (most change) then that is an eigenstate. Multiples of the eigenstate are I believe called eigenvectors. So, for example, Schroedinger's cat has eigenstates of dead & alive (as well as half dead, half alive, almost dead, almost alive, etc, etc) Help?

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  13. Oops. Imperial College. Used to have a good reputation, don't know about now, although I suspect it's till a good place to study. Don't think they've has a laureate on staff for a while tho'. If memory serves, I think Brian May, Queen's guitarist, did his astronomy PhD there. My only real knowledge of it is from a few brilliant gigs back in the seventies by the likes of Queen, T2, possibly the Groundhogs, etc :)

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  14. For some confounded reason, I'm fascinated by chaos theory. Perhaps because I feel it embodies the closest explanation of ME.

    Thanks for the comment on the essay. Not exactly an easy post to comment on. Not sure why I decided to post it again, except as a way to find the place I was at, bring it forth from the abyss and notice how far I've come before I put it away- hopefully forever.

    Sort of wonder sometimes what type of book it all would make, but can't seem to make up my mind wether it is more helpful/hurtful to write about it.

    So, moving on to Quantum Electrodynamcs- hopefully lots about mirrors, of which I have a small fascination.

    The American

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  15. One more question:

    if you have room at the bottom of your next post, could you put some of your favorite science websites? Thanks!!

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  16. I'm afraid I'm of the old school. Books are my my markers, not websites. Books require thought, websites do not! Including this one.

    Mirrors may be a little delayed, MG has a problem with the diagrams! :)

    MY REAL problem with the last (of your posts) is that it might actually be real and everything else becomes disturbing at that point.

    One can only write about what you feel, everything else is intellectual masturbation, be true to to yourself, is there anything else?

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  17. Hmm. Time will tell.

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  18. I have a question about applying heron's formula to finding the unknown side of a scalene triangle. Think you can help?

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  19. Um, this has nothing to do with QM it is schoolboy trig, work it out.The maths is easy!

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  20. Aagh! Left off the smiley from last comment. If it's till a problem after you've tried the maths, come back to me.

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  21. I know you thought I was mad. I was at first, but I did find the answer. You are right to make me try to find it on my own. :)

    So, I have another question, but I don't want to ask it here. Oh, and, the other night on our date, as we traipsed through the wine aisle, my husband suggested I buy a bottle of Penguin for my Penguin friend. I thought it was a cute idea, but no way do I want to spend the tarrifs on some cheap wine if I don't know how good it is. :)

    Questions on refraction and deflection, but will ask later. I have spelling tests to give for the next hour.

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  22. Just so long as you don't think I'm needlessly cruel:)

    Was that 'the Little Penguin' wine from Australia. I've heard good things about it. Although I'm not so keen on the SE Australian whites, I prefer the French versions, the Australians do produce some of the fruitiest and richest reds with their variant of the Syrah grape, Shiraz.

    Sometimes it's enough just to inhale, so berry laden is the scent. Also stops you drinking the whole bottle to yourself, a problem if you have the proper burgundy glasses which hold about half a bottle each if filled to the brim :)

    Ask the other question in an email if it's easier.

    Oh that takes me back, when shopping was a date! We would stagger into the pub for a drink after shopping miles away from where we lived - people can be so strange - especially when they are in love :)

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  23. Totally freaked out by your new post, so came over to see what you had to say.

    Yah, it was a pathetic date, but actually quite fun. We walked down the wine aisle (rarely do we actually indulge) picking out attractive labels, joking about how many redneck, silly, ridiculous and downright low-class labels (Red Truck? wth?) (Yellow Bicycle- charming, but a little too fifties)(Kendall Jackson- sounds like a suit and a tie- not a roll in the hay)

    I was actually looking for one named 'Diablo' because it had a strange effect on me- one I won't ever forget.

    Nevertheless, we amuse ourselves easily. Probably a good sign. At least we won't be the old farts in the grocery store who shop to get out of the house and spend the entire time ramming each other with the shopping cart.

    A date simply means, we held hands and tried to behave kindly toward each other. That's something I have to put on the calendar since it doesn't come naturally. :)

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