Recent content by urnchurl

The concept of wave-particle duality exists even in classical mechanics, look at Hamilton-Jacobi theory (see Goldstein, "Classical Mechanics"). Louis de Broglie exploited this fact to conceive of matter waves, which were already conceived of by Hamilton. However, particle and wave are simply...

PhD age doesn't matter It really doesn't matter what age you get your PhD, what matters is what you do with your degree. The age at which you get your PhD has little if anything to do with intelligence or brilliance, and more to do with circumstances. In this day and age, especially, people...

Anyone know what the typical temperature in the ion tail of a comet is as it nears the Sun? Thanks.

My original question about the electron and positron annihilating has no place in classical theory. One must consider quantum electrodynamics, since afterall, pair annihilation is a consequence of relativistic quantum field theory and is easily handled in QED, as opposed to classical...

That's right, only differences in energy matter (are measurable). There are no absolute energies. I should have remembered that. But isn't the energy of the electric fields just the energy needed to construct the charges? In this case the energy needed to construct an electron or positron is...

What about the energy of the electric fields of the electron and positron?

When finding the amount of energy stored in the electric field of a point particle, one finds that it is infinite (due to the r = 0 limit in the integral of the energy density). Does this mean then that the field will never "run out" of energy? How can the electric field of a point charge, or...

Here is a question, which may seem dumb: Consider an electron and a positron that annihilate, both of which are non-relativistic (taking the observer's frame of reference to be the center of mass frame of the electron-positron pair) so that we only consider their electric fields for simplicity...