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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Intuitive picture for spin-fluctuations contribution to sign reversal of S+- state

In conventional superconductor, electron-phonon interactions lead to negative paring potential and further s-wave superconducting gap. One mechanism for superconductivity in iron-based ...
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flux quantization in superconducting ring

I am trying to understand SQUID microscopy from the ground up, so I am starting with flux quantization in superconducting rings. I found a nice presentation that covers some of the details, but I am ...
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Why do Cooper pairs not bump into other particles?

I sort of get how they get formed and how it works but why do they not bump into other particles? and do the spins have to do with this?
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Zero Field Magnetic Susceptibility of BiSCCO

I have been searching in the literature, with no results, for the (Zero Field) Magnetic Susceptibility of BiSCCO, but I cannot find any article regarding that. Does someone have a reference that ...
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Triplet pairing hard to observe?

I am reading a review on topological superconductivity and Majorana Fermions by Flensberg and Leijnse and at some point they state Triplet pairing has been predicted for the ground state of the ...
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If increasing applying energy to an atom excites electrons, why does electrical conductivity decrease as temperature increases?

Applying energy to an atom makes the electrons jump up to higher energy levels. This is known as excitation. Electrons on higher energy levels are easier to remove from an atom than those on lower ...
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Difference between $\nu=5/2$ quantum Hall state, chiral p-wave superconductor, He 3

I am interested in the relation between the following three phases of matter (in 2D): chiral $p$-wave superconductor (spineless $p_x + i p_y$ pairing) $\nu=5/2$ fractional quantum Hall state A-phase ...
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Superconductors and hoverboards

We know that superconductors are repelled by magnetic fields. The earth has a magnetic field of about $10^{-5}$ Tesla. I just want to know if it is possible to use this property of earth to make ...
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Why do superconductors have a maximum current density?

If superconductors have no resistance, what prevents you making the cross-section as small as you can handle, if there will be no power dissipated anyhow? Is there a limit on the magnetic field that ...
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Superconducting Order Parameter and Time Reversal Symmetry

How to understand the following definition of a time reversal operation $K$ given in the review by Sigrist and Ueda: $$K a_{\mathbf{k},s}^{\dagger} = \sum_{s'} (-i\sigma_y)_{s,s'} a_{-\mathbf{k},s'}$$ ...
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Charging by induction [closed]

When we charge an conductor by induction and grounding, we first bring a negative charge to the conductor. As a result the mobile electrons of the conductor get repelled and stay far from the negative ...
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Is there an electric field within a superconducting inductor?

I have learned that the magnitude of the EMF (potential difference) between the terminals of an inductor is equal to L*di/dt. Does this imply that an electric field does indeed exist in an ideal ...
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If BdG Hamiltonian has particle-hole redundancy, how can it be trusted in discussing the topological properties of superconductors?

In BdG Hamiltonians, the particle-hole symmetry is not a true symmetry but rather a redundancy of description. In my oppinion, saying with the presence of particle-hole symmetry is just saying: hey, ...
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Earth's magnetic field

New researchs found that very high pressure on certain materials may reduce the degree of temperature required to change to superconductor. So is it possible that the high pressure in earth core ...
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References on Josephson ring modulators

I would like some good references on Josephson junctions and, in particular, Josephson ring modulators. I know that Devoret has written a handful of papers and notes on JJs, but I am hoping to find ...
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Is there contradiction between BCS state and the Superselection rule? [closed]

BCS state can be projected into particle number basis. There are different particle numbers in different wave component. But according to the superselection rule there seems to be no such state. I am ...
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How to get the expectation value of the spin of a generate spin triplet states? [closed]

For two spin-1/2 electrons, the general spin triplet states is a linear combination of the three basis states: $\left.|\uparrow\uparrow\right>, ...
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Lorentz force on superconductors?

If current flows on the surface of a superconductor(for both type I & II) and is exposed to an exterior magnetic field, will a superconductor experience a Lorentz force? Knowing that a ...
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Spin interaction of Virtual Phonon's forming Cooper Pairs

Im confused about the spin of virtual Phonons, my lecture notes suggested that even spin bosons repel opposite charges, and it also suggested that cooper pairs form by considering the "Charge" to be ...
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Lorentz force on type II superconductors?

The electrical resistance being zero in a superconductor, if a magnetic field is strong enough to generate vortices where the flux lines will pass through the material, and the current flow is ...
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AdS/CFT and Kondo problem/ Ginzburg-Landau theory

I was reading the review on Unconventional superconductivity by Mike Norman, towards the end (page 22) he comments two things about AdS/CMT: "In the condensed matter context in two dimensions, one ...
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Is there a database or a classification of High-temperature superconductors?

I was wondering if there exists a list with all (or most of) the High-$T_c$ superconductor materials. In particular I'd like to know if there are databases or review that classifies them by their ...
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1D superconductivity does not exist even at zero temperature?

In class Professor claimed that 1D superconductivity does not exist even at zero temperature. I did a preliminary search and found papers on 1D superconductors. Did I or the Prof make a mistake or ...
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Do we always have particle-hole symmetry?

If we write the BdG equation for any model, and double the degrees of freedom (e.g. 4N*4N matrix for a N site chain), then we are guaranteed the particle-hole symmetry. Is there any constraints to do ...
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What's the difference between charge density wave and charge ordering for superconductors

So far, my understanding is that they are the same. Charge ordering is a phase transition and the material will have charge density waves once it's in a charge ordered state...? This sounds too simple ...
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Majorana fermions in s wave superconductor

I need some help to understand the majorana fermions in $s-$ wave superconductor and to check whether following method is correct For $s-$ wave superconductor we can write the Hamiltonian as ...
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Usage of rare earth barium copper oxide (ReBCo) superconductors (for fusion reactors)

Recently, scientist from MIT have proposed a new design for a compact fusion reactor, see for example this ArXiV paper. I do not want to discuss the physics of their reactor but am more interested in ...
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Difference between a Hamiltonian and its mean-field form?

In most solid state physics text books, BCS theory is introduced in the following way: The authors introduce a mean-field parameter (based on the superconduncting pair) and upon that, they reduce the ...
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Three-dimensional flat bands and how to create them?

Consider a three-dimensional non-interacting system with translational invariance. It is easy to create a two-dimensional flat band by putting this system into a uniform magnetic field. The energy ...
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Can the hole concentration of cuprate superconductors generally be determined from lattice parameters?

As it is known, in YBCO superconductors, lattice parameters are strongly dependent on hole concentration, so hole concentration can be determined by measuring the c-axis parameter, see e.g. "Oxygen ...
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Cooper Pair Breaking and Quasiparticle Excitations

My question concerns the breaking of Cooper pairs and the excitation of quasiparticles. At T = 0 all electrons are condensed in the ground state as cooper pairs. If one increases the temperature one ...
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Superconductivity and time-reversal symmetry

Let us consider a system of a 1D edge of a 2D topological insulator in proximity to an s-wave superconductor. The system is described by the Hamiltonian: $$ H =\frac{1}{2} \int \mathrm{d}x \ ...
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Effect of doping in Superconductor

Doping an element (for example element substitution) could be lower down the critical temperature of superconductor, but i don't know the mechanism behind this, is it because more bosons need to ...
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What is crystal “supermodulation”?

I am researching the pair density wave in cuprates, and during my reading I came across a term "crystal supermodulation". I believe it relates to BSCCO. Can anyone give me a definition or give me a ...
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Criticality in BCS Theory

Can someone provide me with a pedagogical introduction into the role of criticality in BCS theory? The QCD condensate is due to strong coupling. The BCS condensation involves only weak coupling - ...
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Why superconductor have vortex

Sorry guys I really don't understand the idea of vortex in superconductor, why superconductors type II have vortices ? Thanks in advance!
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Tunnelling from a normal metal into a superconductor

a similar question has already been asked in the forum but unfortunately I cannot yet comment and still think that some things left unanswered. My question is in general concerning the tunnelling ...
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Particle-Hole transformation in Superconductor

The Bogoliubov - de Gennes equation has a emergent particle-hole symmetry: $$ \mathcal{P}H\mathcal{P}^{\dagger} = -H\text{.} $$ My question is now what happen to the Nambu spinor: $$ ...
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Quasiparticle poisoning in fractional Josephson effect

It is predicted that in the presence of Majorana zero modes, which can mediate a current that is effectively carried by half of a Cooper pair, a Josephson junction can exhibit a periodicity of 4$\pi$. ...
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I need textbooks or articles connected to interplay between superconducting and magnetic layers in thin film heterostructures

I need textbooks or articles connected to interplay between superconducting and magnetic layers in thin film heterostructures. Links would be appreciated though names of articles and textbooks or ...
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Josephson junction exceeding the coherence length of the cooper pair

In this recent paper http://arxiv.org/abs/1504.03286, the authors present the data that they measured Fraunhofer-like diffraction pattern in a Josephson junction with graphene sandwiched between ...
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Exact Diagonalization of a BdG Hamiltonian on a Finite Lattice

I would like to numerically find the edge modes of a $p_x$ + $i p_y$ BdG Hamiltonian. The lattice version is given by H = $\sum\left[-t \left(c_{m+1,n}^{\dagger} c_{m,n} + \text{h.c} \right) - ...
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How feasible is a hoverboard arena using superconductors? [closed]

How feasible would it be to make a hoverboard arena, by analogy with skateboard arena, by having a strongly magnetic floor and a superconducting hoverboard, or vice versa? I don't know the equations ...
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Are there any practical applications of Mott insulators and Superfluids?

The potential applications of Bose-Einstein condensated is discussed here, I was wondering whether anyone could produce a similar argument for Superfluids and Mott insulators. EDIT: I fully realise ...
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BCS/Cooper Pairing in Electrons during Superconducting

Why do electrons with negative charges pair together during superconducting? Since electrons have negative charges, shouldn't they repel each other instead of pairing up? As far as I understand, ...
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Should a superconductor act as a perfect mirror?

I have been told that metals are good reflectors because they are good conductors. Since Electric fields in conductors cause the electrons to move until they cancel out the field, there really can't ...
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Quantum levitation - Real Load Weight

Can you please try to tell if it's real to create a device based on Quantum levitation that can hold adult person a few centimeters above ground. I'm curios because everywhere we see the super ...
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About superconductivity

If I take a magnet and a superconductor than it will expel the magnetic field lines of the magnet. now if there is a coil of wire on the other side of the superconductor and i start to warm up the ...
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How are superconducting magnets powered?

Since the resistance of a superconducting circuit is exactly 0, it would try to draw infinite current from a power source, since P=I^2*R. For a finite power source, I-> infinity as R->0. Correct? ...
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Why is there a superconducting dome in superconductors?

Generally speaking, by the well-known BCS theory, the more carrier density( density of state at Fermi surface) leads to higher critical temperature. However, in many researches, people fond that the ...