Thursday, May 3, 2012

Laue and the relativity crucial step

A reader credits Einstein by making the comment below:
For instance, you cite van Laue in support of your position, yet von Laue later argued for Einstein's crucial originality in his 1905 paper. See "Dismissing renewed attempts to deny Einstein the discovery of special relativity", Roger Cerf, University Louis Pasteur
The 2006 Cerf paper (pdf) says:
Einstein’s crucial step was that he abandoned the mecha- nistic ether in favor of a new kinematics. He saw that the Lorentz group, required by electromagnetic theory, can be derived in all generality by kinematic arguments from the relativity principle, provided an experimental definition is given of the correspondence between times at different loca- tions, based on the constancy of the velocity of light. Max von Laue described this crucial step at the celebration of Einstein’s 70th birthday on March 14, 1949 (the italics are von Laue’s):
“In Lorentz’s published work, his transformation yielded, next to absolute true time and absolute true space, other times and other space co- ordinates that, as far as Maxwell’s equations were concerned, were equivalent to these “true” quanti- ties. But they appeared as properties of the field of mathematics. Only Einstein took the step of justi- fying the equivalence of all these times and all these co-ordinates for all natural phenomena. No one before him had had this insight into the nature of space and time measures.”
Max von Laue was a German physicist who won the Nobel Prize in 1914 and wrote some important early papers on relativity, so his opinion should be taken seriously. He was also a longtime personal friend of Einstein. The “von” Is some sort of nobility title.

However, Laue is demonstrably incorrect about Einstein's "crucial step" being Lorentz transformations applied to all natural phenomena. Lorentz and Poincare took that crucial step, but Einstein did not. Poincare's short 1905 paper said:

But that's not all: Lorentz, in the work quoted, found it necessary to complete his hypothesis by assuming that all forces, whatever their origin, are affected by translation in the same way as electromagnetic forces and, consequently, the effect produced on their components by the Lorentz transformation is still defined by equations (4).
This was published and delivered to Einstein's library a couple of weeks before Einstein submitted his first relativity paper. It was in French and Einstein was fluent in French. Poincare is referring to Lorentz's 1904 paper, which said:
In the second place I shall suppose that the forces between uncharged particles, as well as those between such particles and electrons, are influenced by a translation in quite the same way as the electric forces in an electrostatic system.
While Lorentz was interested in molecular forces, Poincare was interested in the bigger picture, and applied relativity to the speed of gravity, as explained by Carlip.

By comparison, Einstein is missing this crucial idea, and only applies relativity to electromagnetism. Here is Einstein's famous 1905 paper:

They suggest rather that, as has already been shown to the first order of small quantities, the same laws of electrodynamics and optics will be valid for all frames of reference for which the equations of mechanics hold good.
The 1905 sequel starts:
I based that investigation on the Maxwell-Hertz equations for empty space, together with the Maxwellian expression for the electromagnetic energy of space, and in addition the principle that:—

The laws by which the states of physical systems alter are independent of the alternative, to which of two systems of coordinates, in uniform motion of parallel translation relatively to each other, these alterations of state are referred (principle of relativity).

With these principles* as my basis ...

Footnotes * The principle of the constancy of the velocity of light is of course contained in Maxwell's equations.

So this "crucial step" was published by Lorentz and Poincare before Einstein, and Einstein had access to those papers before submitting his first relativity paper, and yet Einstein did not have the crucial step.

I don't know whether Laue was ignorant of these papers, or dishonest, or just praising his friend, or what, but it is remarkable that he has 40 years to find some argument for crediting Einstein and gives such a poor argument. Physicists were incredibly biased towards crediting Einstein, but their arguments do not hold water.

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