What are the major types of waves possible (in principle) in a superfluid? I read about sound waves, temperature waves, sound capillary waves, thin film waves, surface waves, spin waves, shock waves, etc. It's a bit confusing to me. I would like a classification of the major types of waves possible (in principle) in a superfluid. Also, same question for a mixture of two superfluids. I would also appreciate a discussion related to the ways they might have counterintuitive properties, when compared to waves in regular fluids. An answer to at least one of these three questions is OK. Thank you.