Superconductivity is the transmission of current with no resistive losses, and is one of the most active areas of condensed matter physics research.

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Quantum Locking Superconductors on Earth's Magnetic Field

Is the earth's magnetic field strong enough to hold a quantum locked superconductor, or the superconductor wouldn't be able hold its own weight? How strong should be the earth's magnetic field to ...
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How to derive electron number equation of Bogoliubov Hamiltonian using thermodynamic relations.

My question arise from this article: Edge superconducting correlation in the attractive-U Kane-Mele-Hubbard model. I will describe my question in detail so that you might not need to look into that ...
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Solving the BCS Hamiltonian via the Bogoliubov Transformation

I was doing a calculation in Giamarchi's Introduction to Many Body Physics, chapter 3, on BCS theory and second quantization, and ran into some confusion with the BCS Hamiltonian. The pdf is here for ...
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Long range order in the BCS ground state

I am trying to prove the following equivalent form for long-range-order in superconductivity (Annett's book states something like this) : \begin{equation}\lim_{|R-R'|\to ...
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Monopoles and the magnetic Higgs mechanism

In a paper of 't Hooft about the rôle of magnetic monopoles for a model of quark confinement, I don't understand the following sentence (end af paragraph 14) [...] in order for monopoles to ...
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Abrikosov and his fluxoids (why only one ?)

In superconductivity, when we solve the ginzburg-landau equations relative to a 2 dimensional plane immersed in a magnetic field, we find that a periodic lattice of vortices is a solution. When we ...
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Could energy be stored into (not extracted from) the quantum zero point field (like a battery)?

In order to explain the question clearly, I will make a short introduction. In 1962, Josephson predicted that for a sufficiently thin insulating layer, it should be possible for Cooper pairs to ...
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Similarities between laminar-turbulence transition and others like BCS-BEC crossover, quark-hadron transition etc

From my limited readings on fluid dynamics, my understanding is that as the system changes from near-laminar flows to full turbulence, the dimensionless Reynolds number changes from $ R << 1$ to ...
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53 views

Does electrical current have a measurable momentum?

If I were to build a levitating super-cooled superconducting loop of wire with a electrically charged circuit that would discharge its stored energy to produce a large circulation of current around ...
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Why are Cooper pairs formed by electrons of opposite momentum and spin?

I understand that Cooper pair in low-temperature superconductivity are formed by electron-phonon interaction. Normally one then assumes that electrons of opposite momentum and spin are paired. This is ...
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75 views

Toroidal magnet in Tonomura et al. demonstration of Aharonov-Bohm effect

What does the magnetic field look like in Tonomura's toroidal magnet coated with a superconductor? See this paper to find results showing conclusive proof of the A-B effect and flux quantization. ...
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Exact wavefunction of superconducting state

Eventhough we know the mechanism of superconductivity (conventional superconductors) why couldn't we obtain the exact wavefunction of this state? Edit: is there any simpler example in which we know ...
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What is the maximum current carrying capacity of a Josephson tunnel junction?

In 1962, Josephson predicted that for a sufficiently thin insulating layer, it should be possible for Cooper pairs to tunnel between two pieces of superconductor. With a potential difference $V$ ...
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What is a “charged order parameter”?

In condensed matter physics, especially in the context of superconductors, if an author uses the phrase "charged order parameter", what does it refer to? Since the superconductor has a close relation ...
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87 views

Characteristic polynomial of a Matrix

In fact, this problem is more likely to be a math problem. When I read a paper(http://arxiv.org/abs/0707.2875), the author includes the characteristic polynomial for a type of matrix $A_k$ with ...
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41 views

A single valued function from a multi-valued function

In Schrieffer's book "Theory of Superconductivity", there is said when he deals with multiple connected superconductors (and discuss London equations), that if one takes the line integral of the ...
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What happens in a circuit, when the wire and the battery are superconducting. And shorted

When a wire with no resistance is connected to the terminals of an ideal battery, will a current exist in the circuit? If a capacitor is added to the circuit, will it be charged by the battery or will ...
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Simple & intuitive explanation of superfluidity?

I know that superfluidity is caused by the fluid having zero viscosity. This only happens at very low temperature, so the fluid (e.g. Helium-4) is a Bose-Einstein condensate. I also know that in a ...
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Where does the phase difference come from in a Josephson Junction?

When you separate two superconductors by a thin insulating film, a current $I(t)=I_0 \sin{\theta(t)}$ flows between the superconductors, where $\theta$ is the phase difference between the ...
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How Does The Macroscopic Wavefunction Build Up?

How does the macroscopic wavefunction (the order parameter) builds up from zero value to the a finite value when liquid He undergoes a transition from normal to the superfluid state? How does it ...
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74 views

Could a super conductor actually be used to repel gravity? [duplicate]

I've always been interested in anti-gravity and how you could do it. I know that it would make space travel easier because less fuel would be required, but is it possible?
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Commutators of differential and field operators

In $p+ip$ superconductivity, a term in the Hamiltonian (in polar coordinates) is $$ H=\int \mathrm{d}^2\vec{r} \left[ \left( \partial_r -\frac{i}{r} \partial_{\theta} \right) \psi^\dagger(\vec{r}) ...
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Superconducting loop as a particle detector?

Imagine that one has induced a persistent current in a superconducting loop. If a particle interacted with an electron in one of the Cooper pairs then would some decoherence and dissipation occur? I ...
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Drift velocity of electrons in a superconducting loop

Do electrons travel at the Fermi velocity in a superconducting loop? For metals the Fermi velocity seems to be around $10^6$ m/s. So would electrons (in a Cooper pair) travel around the loop at this ...
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Superconducting wire in a Magnetic Field?

A superconducting wire($SC$) is moved rapidly in a magnetic field( $1$ $Tesla$), what would happen to the wire? Are there any forces induced of attraction or repulsion? In a typical conductor, we ...
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Why is there a Majorana zero mode in the $\pi$ flux core of the p+ip superconductor?

In this review paper (http://arxiv.org/pdf/1202.1293.pdf), the author shows that threading a $\pi$ flux through a 2D $p_x+ip_y$ superconductor will trap a Majorana zero mode at the flux center. The ...
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Superconductivity in graphene with spin orbital coupling, is it proper to let the order parameter on two sub-lattice equal?

I am reading this article: Edge superconducting correlation in the attractive-U Kane-Mele-Hubbard model. Considering just the first part of the article, where a negative-U Hubbard model with the ...
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229 views

Seiberg-Witten theory and Superconductivity

There seems to have some (deep) relation between Seiberg-Witten theory and superconductivity. e.g. this Witten paper. Q: Could someone introduce the relations between the twos both physically in ...
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257 views

Bogoliubov - de Gennes Hamiltonian and Zeeman energy

For my system I can write down the Hamiltonian in this form: $$ H = \begin{pmatrix} \epsilon_{1\downarrow}-\mu_{B}B & 0 & 0 & 0 \\ 0 & \epsilon_{2\uparrow}+\mu_{B}B & 0 & 0 \\ ...
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339 views

In superconductivity, is resistance =0?

If a metal shows superconductivity of electricity at definite temperature, then during superconductivity can we consider resistance of metal = 0?
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How does Cooper pairing work?

Cooper pairs are one of the models how superconductivity is explained. What still baffles me is how a vibration of the crystal lattice (the so-called phonon) can interact with the electron (an actual ...
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108 views

Numerical solution of the BCS gap equation, with Coulomb potential

I'm interested in the excitons condensation, which is described by an equation which is very similar to the standard BCS gap equation. I will be referring to this article: ...
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176 views

Why superconductors aren't used in space?

As we all know temperature of space is near to absolute zero.Then why super conductors aren't used there?
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How are superconductors discovered?

How do scientists discover superconductors? Do they test properties of every material available on Earth? Or do they do something mathematically?
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Qubit in Type 1.5 superconductor?

I'm interested in Type 1.5 superconductors, first proposed by Egor Babaev in 2002 and found in the laboratory in 2009 (magnesium dibromide). Such conductors favor small bundles of vortices. The most ...
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Reference for Correlation Lengths of various superconducting materials

Is there a standard reference in which one would look up the experimentally determined correlation lengths $\xi_0$ for various superconducting materials? This is often called the intrinsic coherence ...
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How do photons decay in superconductors?

If $A$ is the vector potential, the London equations imply that: $$(\nabla^{2}-\mu^{2})A=0$$ if there is no external current. This can be interpreted as an effective photon mass and so, light ...
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Does the presence of atoms hinder current flow?

When current flows through a material, electric resistance is observed when the electrons collide with the material's vibrating atoms. My textbook says that when we cool the material till the point ...
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Triangular lattice arrangement of vortices in a superfluid

In a simply connected container containing a superfluid and rotating, there is a net circulation of superfluid. This is found due to the vortices formed, around which the superfluid rotates. These ...
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Falling to closest quantized circulation level in a rotating superfluid

To make a superfluid rotate in an annulus shaped container, we start with a normal fluid, rotate the container, then cool it to below critical temperature to get a rotating superfluid. The allowed ...
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What is the difference between diamagnetism and superconductivity?

Basically, What is the difference diamagnetism and superconductivity? As far as I understand, diamagnetism comes from the fact, that all electrons in a solid, when exerted by an external magnetic ...
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Magnetic field exclusion and retention in superconductors

I'm studying the behaviour of superconductors in different cases, and I can't understand this. We have a superconducting cylinder with a coaxial hole inside (vacuum). When the cylinder is cooled ...
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Does Fluctuation-exchange (FLEX) approximation including spin-orbit coupling (SOC) exist?

FLEX method was invented by N.E.Bickers and D.J.Scalapino in 1989 (PRL 62,961; Ann. Phys. 193,206). Later it was extended to multi-orbital system (T.Takimoto,PRB,69,104504). But I don't find FLEX ...
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Josephson effect - fractional or not

It is well known that a current proportional to $J\propto\sin(\phi_1-\phi_2)$ flows when two superconductor with phases $\phi_1$ and $\phi_2$ are connected. Also, a current which depends on the ...
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Superconductivity: why can't the resistance reach 0?

When we study electricity in high school we examine the resistance of conductors and its relation with temperature. Diagrams show the relationship at the beginning is pretty much a linear with ...
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Do Cooper pairs act like Cheshire cats?

Could the pairing up of electrons be explained by their spin being in a different position? What would separating the spin from an electron in matter do in theory?
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Acting on a current density operator in second quantization

I have a current density operator in second quantization in the form: $\hat{J} = -i\left(\psi^\dagger \partial_x \psi - (\partial_x \psi^\dagger) \psi \right) $ operating on some state: $|\phi ...
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164 views

BCS Theory of Superconductivity

I'm currently taking an introduction to Solid State Physics class, and is now on the subject of superconductivity (SC). Currently I'm reading about the BCS theory, and how this works on a microscopic ...
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Bulk modulus of Liquid helium and first sound

Does anyone know where to find the bulk modulus of liquid helium ? I've been looking all over the internet but everywhere I get N/A. Any tips ? I'd need it to estimate the speed of first sound in ...
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What is the relation between vortex and quantized magnetic flux in superconductor?

A vortex is a topological defect of the order parameter. As far as I am concerned, I think a vortex is a phase singularity point and a vortex always has a quantized flux. And we know that the magnetic ...