# Michelson-Morley meets Quantum Mechanics

The Michelson-Morley experiment (read the original paper here) is one of the first textbook experiments that you learn about in support of the light postulate. From this postulate, together with the principle of relativity, it is easy to derive the group of Lorentz transformations, which form the basis for special relativity theory. (Honesty note: some more mild-mannered principles are also required for this derivation, such as the homogeneity and isotropy of space.)Of course, it is possible to derive the Lorentz transformations without the light postulate (Torretti 1983, ch. 3). And famously, historian Gerald Holton revealed in an interview that Einstein was not influenced by this experiment when developing the theory of special relativity. (What experiments did influence him still remain a mystery, at least to me).

So when I read this article, somehow I just wasn’t that shocked.

The guy is suggesting that the Michelson-Morley experiment could have been understood within Galilean kinematics, using the fact that in traditional quantum mechanics, phase-difference between transmittor and receiver is a velocity-independent quantity.

This now seems like a bit of a crank-trick to me. But the general idea that there might have been other ways to explain the experiment is interesting.

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