Recent content by guyingfei

The concept of “fields” told us that our physics is local, while the concept of "entanglement" seems to say that there is something nonlocal So I wonder whether our physics laws are local?

When you consider a "effective theory" you don't care what on hell the particle is, a hole or a real particle.

I think that is because photon is gapless, which means you can creat or kill one very easy. While the chemical potential is a parameter which describe "how difficult" you put one particle into your system. In this way, all particles(including quasi-particles) with zero mass will have zero...

Sorry, I misuse my friend arielleon's account. That's me

I think superfluid is clear known, but quantum fluids is a much 'wide' concept. quantum fluid= interacting atoms or electrons without long range order?

I am not very clear about your question. But I guess that is the mean-field solution, so the 4-operator reduce to 2-operator with some proper approximate

I guess it will open a gap because it break the space inverse symmetry. You can get help from the famous Haldane Model.

I regard chemical potential as a parameter to control the particle numbers. I hope the idea could help you. I remeber chemical potential was first introduced as lagrange mutiplyier in statistics mechanics.