A What Other Symmetries Exist in Superfluids?

[Superfluid universe]

I am reading "Introduction to superfluidity" by Andreas Schmitt. He mentions the global symmetry U(1). What other symmetries are there in superfluids?

Thank you.

 

[Superfluid universe]

Yes. I can add more information. For example, I've read that in superfluids there is a global U(1) symmetry. I was asking if there are other symmetries as well. :)

 

[MathematicalPhysicist]

You can read the last section of Kardar's Statistical Physics of particles the 7.7 section that discusses the superfluid He^4.

I am not sure he says anything about the symmetries of this supefluid, but that's all that I read about superfluid.

 

[Superfluid universe]

Thank you, MathematicalPhysicist.

Another example : https://arxiv.org/pdf/1206.3906.pdf This article talks about global u(1) symmetry in superfluid neutron stars. It says that the goldstone mode for that symmetry breaking is a phonon. I was asking for other symmetries that exist in superfluids.

Thank you.

 

[MathematicalPhysicist]

If you searched google for "symmetries of superfluids" and found that there's no mention of other symmetries then it might mean there are no currently known symmetries other than U(1).

 

[Superfluid universe]

Hello Mathematicalphysicist. In the book "Introduction to Superfluidity" by Andreas Schmitt, it was mentioned that U(1) was the simplest symmetry, which means there are other symmetries too. ( in my opinion)

https://books.google.bg/books?id=vtQlBAAAQBAJ&pg=PA33&lpg=PA33&dq=introduction+to+superfluidity+simplest+symmetry&source=bl&ots=8e-6J1Ifn4&sig=KEovmOSYsVYIrJhU_5v31A2wE7k&hl=bg&sa=X&ved=0ahUKEwj-rKqU2ZbaAhVQyqYKHYS8BnUQ6AEIJzAA#v=onepage&q=introduction to superfluidity simplest symmetry&f=false

page 33 says 'U(1) is the simplest continuous symmetry given by one real parameter"

 

[muscaria]

What other symmetries are there in superfluids?

It depends on what kind of superfluid you have in mind, but for typical ones which I assume you have in mind (described by the Gross-Pitaevskii equation) you also have space-time symmetry transformations, instead of the field transformations you have already mentioned (U1 gauge symmetry). For instance Galilean symmetry, which includes translations, rotations and boosts to reference frames moving with uniform velocity.