Hi all. Just a quick question, probably a silly one. Due to wave-particle duality all particles have both wave-like and particle-like behaviors. The wave-like properties of, say, an electron can result in an electron interference pattern. So, my question is: Can waves of different things interfere? For example, an electron "wave" and an EM "wave"? I'm thinking no. It doesn't quite make sense to simply "add" two different types of waves to produce some sort of "mixed" interference. However, I'm looking for a bit of physical reasoning beyond this. Thanks!