Quantum theory shows that particles such as photons, protons, and electrons
are excitations of quantum fields. From a great distance,
we distinguish a star from a planet because the star has a point-like appearance,
whereas a planet, in the telescope, has a diameter.
I should perhaps not be bringing Pound’s vortex
into the context of the magnon,
since it is more analagous to the roton quasiparticle.
See also in The book of science:
Readings on wikipedia: