I'm having trouble understanding some things about the De Broglie relation, λ=h/p 1. A massive system, such as an atom, is a composite of several particles (protons/neutrons, electrons), each of which is a matter wave with its own wavelength, according to De Broglie relation. But the atom considered as a single particle, has its own (lower) wavelength. How do these individual λ_proton, λ_electron, etc. waves combine into the single λ_atom wave? In other words, what does it mean that the atom is a matter wave with a single wavelength - isn't it a composite of its many individual component waves? 2. Actually, even a single particle does not have a single well defined wavelength - the fourier decomposition of its wave function produces many component wavelengths - so what does the λ in λ=h/p stand for then?