Topological excitations
will become a part of the book on Advanced Quantum Mechanics I write with Jeroen Danon. I’m currently squeezing the material to a chapter devoted to superfluidity. It’s a difficult piece of writting: yet I dream it will be a good one.
The trick to implement the concept is to consider the superfluid in lower dimensions where vortices have finite energy and can be regarded as elementary excitations. I also hope to be able to say something about Feynmann’s roton variational function: a gem almost forgotten in modern education.
