| Popis: |
The Mott problem asks: Is there a microscopic physical mechanism - based (explicitly or implicitly) only on Schroedinger's equation - that explains why a single alpha particle emitted in a single spherically symmetric s-wave nuclear decay produces a manifestly non-spherically-symmetric single track in a cloud chamber? This is a variant of the more general quantum measurement problem. Earlier, we proposed such a mechanism, drawing on quantum-mechanical Coulomb scattering and the thermal behavior of supersaturated vapors. Our analysis implied that, in a large enough sample, the probability that a track originates at distance R from the decay source is proportional to 1/R^2, with a proportionality constant which we expressed in terms of more fundamental parameters involving diverse physical processes, but were unable to estimate at the time. More recently, we tested the 1/R^2 law opportunistically using pedagogical cloud chamber video posted on the Internet. In the present paper, we draw on the chemical physics literature for an independent estimate of the proportionality constant. The estimate is rough, but within about 1.7 orders of magnitude (factor of 50) of a rough value that we derive directly from the video data. Given the crudeness of the experimental data, the roughness of the numerical estimates, and the extreme spread of concentrations involved (air molecules vs. subcritical vapor clusters of specific sizes), we view this level of agreement as significant, at this stage in the theory's development. |
