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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Interpolation formula for BCS superconducting gap

In BCS theory, the superconducting gap is given by solving at different temperatures the integral ...
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Expansion in Pauli matrices - coefficient set equal to zero

Lets say you want to calculate the gap parameter $\Delta$ for a superconductor. One approach that is often used is the self-consistency approach for the self energy. Details can be found in this paper ...
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Superconductor in a parallel vs perpendicular magnetic field

My question concern's the huge difference in critical fields regarding a thin superconductor(SC) which is surrounded by a magnetic field. lets imagine the SC is a thin film in the x-y Plane: Applying ...
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A magnet floating due to Meissner effect

If a magnet is floating due to the Meissner effect, can the magnet rotate freely under influence of external field in spite of the presence of north and south pole in it ?
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Superconducting electromagnets?

Is it true that superconducting electromagnets don't need any power? So... energy to created a magnetic field via a superconductor would be zero? Since resistance is zero, does that also mean that ...
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What is the difference between a Josephson junction and a superconducting tunnel junction?

I am wondering if there is any difference between a Josephson junctions and superconducting tunnel junctions. I appreciate a good explanation.
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Are there topological non-trivial states in zero dimension?

The periodic table of topological insulators and superconductors suggests that there can be topological non-trivial phases in zero dimension in non-interacting system with certain symmetries. Are ...
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Does the real part of the inverse dielectric function have to be negative at some point for Cooper pairs to form?

Electrons naturally repel one another. However, in a superconductor, a phonon-mediated interaction causes the electrons to have a weak attractive interaction. Suppose that the interaction between two ...
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How do Cooper pairs form?

How can Cooper pairs formation be possible, even though it is made up of two likely charged particles? (those particles being electrons)
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Question about superconductivity

A long cylinder of radius $R$ is made from two different material. Its radius $r<r_0$ $(r_0<R)$ part is a material with superconducting transition temperature $T_1$, and its $r_0<r<R$ ...
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What kinds of behavioural anomalies can a zero-field-cooled (ZFC) / field-cooled (FC) split indicate?

If a material shows a spiltting in the ZFC and FC curves, is it necessarily superparamagnetic, or could there be any other reason for the irreversibility? I have heard spin glasses also show ZFC-FC ...
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Chemical potential of Cooper pairs

Consider a BCS Hamiltonian with an additional term that reads: $i\mu c_k^+c_{-k}^+ + H.c$. What is the meaning of $\mu$? How one can write this term in real space, and does this term show up in the ...
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About Majorana fermion in spin-orbit coupled quantum wires

Majorana mode has attracted great theoretical and experimental interest. The experimental evidence is obtained in quantum wires. The origin theoretical proposals of quantum wires are the papers: 1、R. ...
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What determines the spatial variation in phase in a superconductor?

I'm assuming that since a superconductor is in one common wave function, the time evolution is governed by the typical global phase variation: $$ \psi (t) = e^{-\frac{i}{\hbar}E_nt}\psi(0) $$ ...
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physics of the beaker experiment for superfluid helium

here is an illustration and explanation of the beaker experiment over superfluid helium: So, according to this experiment, can anyone say what is the cause? I mean the superfluids are disconnected ...
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Can current be induced in a superconductor?

Moving a magnet close to a conductor induces a current. If it consists of a superconducting material with resistance $R=0$, then my textbook says: Then the induced current will continue to flow ...
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Could some astronomical objects have superconducting properties?

The colder it is, the more efficient the superconductivity process works. And as we know, if there is no star nearby, space gets pretty cold. I do appreciate that many condensed, burnt out, stars ...
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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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Lorentz force on superconductor vortices

I am reading a paper on superconductivity and in it it says that the vortices are subject to a Lorentz force given by $$\vec{F}_L=\frac{\Phi_0\vec{I} \times \vec{H}}{cH}$$ Here $\vec{F}_L$ is the ...
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Question about Meissner Effect video

In this video, what material is on top of the superconductor disk that keeping it cold? Is it just a circular chunk of dry ice? http://www.youtube.com/watch?v=Ws6AAhTw7RA I'm planning on recreating ...
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Is the first excited state of a superconducting qubit a stationary state?

A superconducting qubit is essentially an anharmonic oscillator with uneven spacings of the eigenstates. These states are eigenstates of the overall hamiltonian, which should mean that it is an energy ...
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Topological superconductors: what is the role of spin-orbit coupling? Are there topological non-trivial states without spin-orbit?

Let's say I have a one-dimensional system with particle-hole symmetry and with broken time-reversal symmetry. As a consequence, the chiral symmetry is also broken in this case (the chiral symmetry ...
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Superconductors in a magnetic field — mixed phase

In my Stat Mech class we're learning about the phase transition between superconducting and non-superconducting metals in the presence of a magnetic field (Chapter 7, Kittel). I understand that the ...
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What is a d + id superconductor and why does it break time reversal symmetry?

There are a lot of publications dealing with d-wave and d + id superconductivity, but I found no satisfying answer what exactly makes a superconductor d + id and why they break time reversal symmetry. ...
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Ampère's law and superconductors

I have been reading about superconductors and emerge me a inquietude about the explanation of existence of currents inside the superconductor while their magnetic field (inside too) is zero. Based in ...
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Does a magnet floating over a superconductor slowly fall and take infinite time to stabilize?

The reasoning being that as the magnet moves towards the superconductor it induces an opposite magnetic field, until the latter rises sufficiently to equal the weight of the magnet. Except that looks ...
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Questions concerning BCS theory (particularly the “pairing Hamiltonian”)

I've been reading up about the BCS theory of superconductivity, and the treatments I've seen begin rather mysteriously with a Hamiltonian that (in the language of second quantization) looks ...
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What determines a state of matter?

Earlier I studied about the three states of matter-gaseous,liquid ans solid. Then, I came to know about Plasma and Bose-Einstein Condensate. Now, scientists are trying to explain superconductivity as ...
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Magnetization of a type I superconductor

How could I derive an expression for the magnetization of a spherical type I superconductor? I've searched in many sites but I haven't found any way to proceed.
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What kind of free energy do we use for a superconductor in a magnetic field?

My reasoning is as follows (using Gaussian units): Start from the second law: $$dU=TdS+dW,$$ where $dW$ is the work done by the magnetic field. To derive $dW$, we consider a solenoid with current ...
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Lifting capacity of superconductors

How does the strength of the magnetic field the superconductor is exposed to affect its ability to levitate/lock heavier objects? Or is there no relationship (for superconductors) between magnetic ...
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The requirements for superconductivity

Which properties are sufficient evidence for a material to be not superconducting? I am looking for a set of statements like If the material is semiconducting, it is not superconducting Edit: I ...
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Mutual inductance versus self inductance of two parallel thin-film wires

I am considering the scenario of two long superconducting thin-film wires (thickness << width << length) running parallel to eachother. They carry a current density that is as usual peaked ...
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Why is a transmon a charge qubit?

The classic charge qubit is the cooper pair box which is a capacitor in series with a Josephson junction. In my understanding, by changing the gate voltage at the capacitor, one can create a ...
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Is there net current through a Josephson junction at zero bias?

It is widely stated that when a Josephson junction is placed in a superconducting circuit, the cooper pairs can tunnel through and create a net current without a bias voltage. However, given that the ...
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Does flux quantization require uniform pair density?

Consider a superconducting circuit with a "box-like 8" geometry like [|] (ie. two square loops which share one side of wire). Here we can have three different currents ($I_1=I_2+I_3$, see H. J. Fink ...
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How to compute the density of state from the Green function?

I'd like to plot the density of state (DOS) for a specific system, say an s-wave BCS superconductor, the Green function of which is ...
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Why is the quench temperature fluctuation not a concern for maglev trains?

I am having trouble discovering why temperature fluctuations and magnetic field fluctuations are not a stability concern for superconducting magnetic levitation trains. I am under the impression that ...
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can we have a phase transition from superconductor to the normal only by applying magnetic field?

for superconductors we have a phase transition diagram. according to that phase diagram in a temperature below Tc, we can only increase the applied magnetic field to make a superconductor a normal. ...
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How do superconducting materials float in magnetic field?

The movie Avatar got me interested in the subject, but so far I only found sophisticated articles loaded with unfamiliar words. Is there a simple way to explain how magnetic field affects ...
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Superconductivity in space [closed]

Do you think you could use the drastically reduced temperatures in space to create superconductivity on the outside of a ship, for power on the inside, preventing overheating, and a near constant ...
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Is current in superconductors infinite? If they have 0 resistance then I (V/R) should be infinite? [duplicate]

I learned many years ago that according to Ohm's law, current is equal to voltage divided by resistance. Now if superconductors have zero resistance then the current should be infinite. Moreover the ...
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Meissner effect and levitation

In a field less than critical field, decreasing the temperature below the critical temperature will eliminate the magnetic field inside a superconductor and increase the magnetic field around it. ...
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How can Ohm's law be correct if superconductors have 0 resistivity?

Ohm's law states that the relationship between current ( I ) voltage ( V ) and resistance ( R ) is $$I = \frac{V}{R}$$ However superconductors cause the resistance of a material to go to zero, and ...
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what experiments can be used to distinguish between s-wave and d-wave superconductivity?

What are some experiments which be used to distinguish between s-wave and d-wave superconductivity?
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Analogies between Fraunhofer diffraction and Josephson junctions

There are several analogies between diffraction patterns and Josephson junctions, especially between a double slit experiment and two Josephson junctions in a superconducting ring (like this): Both ...
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The wavefunction of the superconductor A consists of two parts: B and C

In reading this article, I come across this paragraph: The pink marked place is where I can't understand, why can we use direct product of the former but not the later? This is may be a basic ...
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Does the Meissner effect only effect magnetic fields?

I find this effect very interesting and was wondering what tests have been performed to check its effects on other fields? Also a side question related to this effect, can it trap a magnetic field. ...
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How much charge per unit time passes with the Josephson current

I wonder how does the simple defintion of a current $I = \frac{dQ}{dt}$, i.e. charge per unit time which passes through some area, is applied to the Josephson effect. If I have a Josephson junction ...