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.