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Questions tagged [superfluidity]

A flow with no viscosity

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Landau critical velocity and sound velocity

The definition of Landau critical velocity is $v_L=\min_{q}\{\frac{\omega(q)}{q}\}$, where $\omega(q)$ is the spectrum of excitations. The viscosity vanishes when the object is moving through the ...
199 views

Superfluidity book recommendation

I'm preparing for a senior undergrad seminar on superfluidity and quantized vortices, and my professor seems to prefer old textbooks, so I wondered what modern (~90's onwards) books on these phenomena ...
61 views

Energy of the excitation in the superfluid

According to the chapter 1.3: Superfluidity, from the book "Methods of Quantum Field Theory In Statistical Physics by A.A Abrikosov, it is written that Consider a Bose liquid at absolute zero, ...
176 views

Is gapless spectrum necessary for superfluity

In 3D interacting Boson system, the condensate leads to a gapless spectrum and superfluidity. The same gapless spectrum for 2D with quasi-condensate (correct me if it is wrong ). I am wondering if it ...
255 views

788 views

Can superfluids pass through ordinary baryonic matter?

Since superfluids consists of integer spin bosons or effective bosonic Cooper-paired fermions, Pauli Exclusion Principle does not apply to them. They can thus occupy the same quantum state as any ...
53 views

Capturing superfluid condensation with exact diagonalization

Doing exact diagonalization on bosonic systems is tricky, because the possibility of multiple occupancy means that even the single-site Hilbert space is infinite-dimensional. It's my understanding ...
283 views

Rotation of superfluid

I have two questions related to rotation of superfluids. Firstly, what is the main reason that superfluid cannot rotate as a whole object ? (I found that it is true in Landau's Statistical Physics but ...
1k views

What is the difference between superfluidity and Bose condensation?

My question is about zero-temperature ground state of a Bose system. Suppose that the system stabilizes a BEC order parameter, say $\langle b^+ \rangle$, and fixes its phase. Is this a superfluid? And ...
627 views

What is the Single Mode Approximation?

When Girvin and co-workers solved the excited collective modes called magneto-rotons in Fractional Quantum Hall liquids, they used something called the Single Mode Approximation (SMA). My question is: ...
285 views

Nomenclature clarification concerning solitons

My experience with solitons is restricted to the classical setting, namely solutions to the quartic interaction $\phi^4$, the Sine-Gordon equation, and Korteweg–de Vries equations. I was explicit to ...
88 views

Where should I start learning Landau's theory of superfluidity?

Where should I start learning Landau's theory of superfluidity? For a second year undergraduate.
In the theory of superfluidity in weakly interacting Bose gases, one finds that in the symmetric phase the exctitations have the dispersion relation $\omega = \frac{k^2}{2m}-\mu$ with gap \$\Delta=-\...