Recent content by Aethermimicus

I'm struggling to understand the relation between phi4 theory,non-linear sigma model and ferromagnets. I've read this in a paper(Phys.Rev.B14(1976)3110):'It is possible to describe the long-distance behavior of the Heisenberg ferromagnets in two different ways:the phi4 theory which corresponds...

Thanks! I've also found an article. Christian, R.S., Davis, R.E., Tubis, A., Anderson, C.A., Mills, R.I., and Rossing, T.D. (1984). Effects of air loading on timpani membrane vibrations. J. Acoust. Soc. Am. 76, 1336-1345.

I'm trying to understand the function of the air cavity inside drums. I've read that 'The air cavity inside the drum will have a set of resonance frequencies determined by its shape and size. This will emphasize some frequencies at the expense of others.' Then what are the resonance...