Explaining Quantum Mechanics to My Daughter
My daughter saw an article in the student newspaper at her university about the recent result on neutrino oscillations from the MINOS experiment. She thought the write up in the newspaper was dumbed down and asked me what I thought about it. In an uncharacteristly sarcastic moment I wrote back.
Yes, but are you surprised that it is dumbed down? Would you like me to explain in its fully gory detail? It turns out that eigenstates of flavor are not eigenstates of mass, so when a neutrino is produced in a weak interaction it is a mixture of mass eignstates. As the neutrino propagates the mass eigenstates evolve in time at a different rates so the relative strength of the two or three eigenstates changes with time and the probability of observing any particular flavor eigenstate therefore evolves with time.
I did my dissertation on neutrino oscillations and I also worked on B meson oscillation measurments. These are a fascinating quantum phenomena that that can be explained quite nicely using the quantum mechnics from a sophmore level university modern physics class, but first you have to learn about eigenvalues and eigenstates. There are classical analogs to the quantum oscillation like the normal modes of coupled oscillators, but I do not find them quite satisfactory. The normal mode of an oscillator just does not seem as fundamental as the flavor of a neutrino. The role of eigenvalues and eigenstates to quantum mechanics is so fundamental that one cannot even discuss quantum mechanics without them.
I have trouble explaining how exciting I find this physics to people who have not studied quantum mechanics.