Whenever we have a "macro" object like a buckyball, it has many electrons and quarks if not something more fundamental, all of which have their own wavefunctions that interact with each other. But in the double-slit experiment, we show that the minimas and maximas occure for only photons/electrons with a single wavelength. If we take a combination of wavelengths, like visible light, we won't have a distinct interference pattern. (although we do see some separation at the edges of bright intensity bands) Then, how is it possible that something that is a combination of various matter waves with different wavelengths like a buckyball, also shows the same kind of interference pattern?
$\begingroup$ This question would benefit from some references to such experiments, because the issues you raise are certainly addressed in the papers describing the experiments for a skeptical audience. $\endgroup$
Commented Nov 18, 2019 at 19:51$\begingroup$ It would be too good to be true if the interference pattern for a certain particle depended sensitively on the details of its internal structure. This would be like an infinitely powerful microscope, and we wouldn't need to build particle accelerators. $\endgroup$
Commented Nov 18, 2019 at 23:43$\begingroup$ @Rob Can I please ask you to add some links to the question that you find are suitable and would benefit a wide audience? I came across this question after reading some articles on how "recently" double slit experiment was tested on macro objects. $\endgroup$
Commented Nov 20, 2019 at 12:19$\begingroup$ @BenCrowell, does it not happen, at least in case of protons? i.e the wavefunctions of quarks being combined to give wavefunction of proton or neutrons? Also, to write the hamiltonian of any system, don't I need to kow the internal workings of it? Which means, basically I shall be including wavefinctions of internal particles, if any. $\endgroup$
Commented Nov 20, 2019 at 12:36$\begingroup$ @Astik Generally we expect the person who asks the question to do their own background research. If you "came across this question after reading some articles," those articles are a good place to start looking for links (or are good links themselves). $\endgroup$