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

learn more… | top users | synonyms (1)

5
votes
1answer
311 views

A question on the doped Kitaev-Heisenberg model?

Recently, some groups have studied the effects of doping the Kitaev model on honeycomb lattice(e.g.,http://arxiv.org/abs/1109.6681 and http://arxiv.org/abs/1109.4155) and their calculations show the ...
4
votes
2answers
2k views

Why does a superconductor obey particle-hole symmetry?

We normally solve the Bogoliubov-de Gennes (BdG) equations in order to compute the energy spectrum of a superconductor. The Nambu spinor is a common object that is used in formulating these equations. ...
20
votes
4answers
793 views

What observables are indicative of BCS Cooper pair condensation?

What observables are indicative of BCS Cooper pair condensation? "Thought" experiments and "numerical" experiments are allowed. This question is motivated by the question Has BCS Cooper pair ...
3
votes
1answer
299 views

Flow of supercurrent in a superconductor

I have two questions one practical and one theoretical. Even though I have a decent understanding of superconductivity both phenomenological as well as theoretical (i.e. BCS), some things just slipped ...
0
votes
1answer
234 views

Effect of strength of magnetic field on the height of a levitating superconductor?

Quantum levitation, flux pinning -- basically, when a superconductor floats above a permanent magnet, is really fascinating. But does the strength of the magnetic field influence the superconductor's ...
5
votes
4answers
277 views

Induction cooker + superconductive pot

What will happen if I put a super-conductive object on an induction cooker, and turn the cooker on?
4
votes
2answers
1k views

Superconducting gap, temperature dependence: how to calculate this integral?

Tinkham (page 63) states that the temperature dependence of the gap energy of a superconductor $\Delta(T)$ can be calculated using the following integral: How can this actually be carried out? I am ...
3
votes
1answer
533 views

Zero Resistance in Quantum Hall Effect and Superconductivity

What is the difference between the zero resistance of $R_{xx}$ in integer quantum Hall effect and the zero resistance in superconductivity?
7
votes
3answers
581 views

Superconducting Wavefunction Phase (Feynman Lectures)

In Volume 3, Section 21-5 of the Feynman lectures (superconductivity), Feynman makes a step that I can't quite follow. To start, he writes the wavefunction of the ground state in the following form ...
1
vote
2answers
346 views

Superconductor general concept questions

I was thinking about building an electric motor using superconductors and I have some general concept questions in regards to how the behavior might be different from ordinary wires. The Meissner ...
3
votes
0answers
52 views

What is meant by the quantum integrity in a superconducting loop

I encountered this in the context of using squid microscopy to test for d-wave pairing in an iron arsenide superconductor where the goal of the experiment was to detect half integer flux quantum ...
3
votes
1answer
86 views

What are virtual excitations in the context of superconductors?

In a superconductor I have read that the energy gap can be defined as the energy difference between the ground state and the virtual excitations of the system. Is this the energy required to form a ...
5
votes
2answers
2k views

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 ...
5
votes
2answers
1k views

What do massive photons have to do with superconductivity?

I keep reading that the idea of massive photons leads to an explanation of the Meissner effect but I fail to see how photons are involved with the repulsion of fields inside a superconductor. How ...
6
votes
3answers
676 views

Why can't a superconductor make a DC motor self sustaining?

Superconducting wire can host a low current magnetic field. I do not know if it supports a corresponding electrical field. Can a superconducting wire that sustains a current accelerate a DC motor? ...
12
votes
4answers
1k views

Usage of helium in MRIs

More and more articles pop up on the shortage of helium, and on the importance of it. Its usage in MRI's spring to mind for example. I looked it up and found out that helium is used for its 'low ...
0
votes
1answer
70 views

Superconducting nanowire in a parallel magnetic field

Consider a nanoscopic wire (with radius $R$) of superconducting material. The wire lies along the $z$-axis and a magnetic field $\mathbf{H}_a = H\mathbf{e}_z$ is applied. The magnetic field is too ...
5
votes
2answers
272 views

Meissner Effect for Type-II Superconductors

I was wondering whether the breakdown field strength for the Meissner effect may be attributed to the Zeeman effect? I can see the latter (along with the Stark effect) to be more analogous to electron ...
2
votes
4answers
259 views

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 ...
8
votes
2answers
504 views

What does “particle number conservation” mean in condensed matter physics?

What exactly does it imply about a condensed matter system to have particle number conserved or not conserved? For example, why does the superconducting phase break particle number conservation while ...
1
vote
1answer
106 views

What papers detail the early research on heavy fermion superconductors?

Can someone point me to the papers detailing when/where/how heavy fermion superconductors were first synthesized, tested and documented?
4
votes
2answers
385 views

Has BCS Cooper pair condensate been observed in experiment?

Feshbach resonance in s-wave scattering states a BCS Cooper pair condensation at B-field just above the resonance where the scattering length a <0. Just wondering if the condensation has been ...
6
votes
2answers
811 views

Why are Topological Superconductors hard to make?

Topological insulators (TI) have already been made in lab. Topological superconductors (TSC), being close cousins of TI, seem harder to make. Why is that? It seems that materials in connection with ...
4
votes
1answer
819 views

Looking for a complete review of the BEC-BCS crossover

I'm looking for comprehensive review of the BEC-BCS crossover, both from a theoretical point of view, and from a experimental one. Even something at textbook level, but exhaustive, would be OK, but I ...
10
votes
3answers
418 views

What does the term liquid mean in condensed matter physics?

In condensed matter physics, people always say quantum liquid or spin liquid. What does liquid mean?
2
votes
1answer
128 views

Crystal magnetic response only skin deep?

The Hamiltonian for a single electron in a magnetic field reads $$H=\left(\frac{{\bf p}^{2}}{2m_{e}}+q_{e}\phi\right)+\mu_{B}\left({\bf \hat{L}}+g{\bf \hat{S}}\right)\cdot{\bf ...
4
votes
1answer
147 views

What is the smallest amount of He you can use to cool a superconducting magnet?

This is an engineering question, but it is adressed to physicists who build accelerators. This question: An electromagnetic space elevator? notices that a NbSn superconducting ring around the equator ...
4
votes
3answers
362 views

In what way do Cooper pairs of electrons bond and stay bonded in superconductors?

I understand how electrons initially move into another's vicinity, but nowhere can I find a fathomable answer to this. Also, does the pairs forming 'a condensate' mean a Bose-Einstein condensate?
1
vote
2answers
287 views

What exactly is superconductivity?

Does superconductivity mean that the coulomb force or some magnetic force has gone up? I guess that it applies only to wires which get less resistance due to cooling... Is this wrong? Also, Are there ...
7
votes
1answer
621 views

Relativistic drift velocity of electrons in a superconductor?

Is there a formula for the effective speed of electron currents inside superconductors? The formula for normal conductors is: $$ V = \frac{I}{nAq}$$ I wonder if there are any changes to this ...
1
vote
2answers
433 views

Practical issues with Superconductivity

Well, Is it really possible to maintain such low temperatures required for super-conductors (taking High-temperature superconductivity into account) over large distances? What I say is - Even if we ...
2
votes
0answers
41 views

What is the status of the Gennes - Alexander theory of Superconducting Micronetworks?

I have started reading the book Connectivity and Superconductivity which gives an introduction to the ideas of de Gennes-Alexander theory. My question is: how is this theory regarded experimentally? ...
6
votes
3answers
686 views

Aharonov-Bohm Effect and Flux Quantization in superconductors

Why is the magnetic flux not quantized in a standard Aharonov-Bohm (infinite) solenoid setup, whereas in a superconductor setting, flux is quantized?
6
votes
4answers
294 views

Intuitive explanation to why superconductivity breaks at high temperatures

I was recently caught up in a situation where I tried to explain to someone with only vary basic knowledge of physics (notion of atoms and electrons, etc.) what causes superconductivity. One thing I ...
9
votes
3answers
763 views

How come a photon acts like it has mass in a superconducting field?

I've heard the Higgs mechanism explained as analogous to the reason that a photon acts like it has mass in a superconducting field. However, that's not too helpful if I don't understand the latter. ...
1
vote
1answer
172 views

Superconductor: What form of paramters (like London penetration depth) to use?

I am dealing with thin film and LN2 temperature, and am trying to calculate values such as the Pearl Length, but am trying to find clarification as to which value of $\lambda_L$ to use in this case. ...
0
votes
1answer
308 views

Faraday's law and superconductivity

According to Faraday's law of induction, volts = -Number of coils in a solenoid * change in strength of magnet / change in time. This doesn't take into account distance or speed, only time. If amps = ...
2
votes
4answers
5k views

If something has zero resistance, does it have infinite amperage?

If amps = volts / ohms, and ohms is 0, then what is x volts / 0 ohms?
4
votes
3answers
2k views

Quantum levitation (locking) 3mm thick disk could carry 1000kg small car claim

I watched this TED presentation: http://www.ted.com/talks/boaz_almog_levitates_a_superconductor.html It is about superconductivity and quantum levitation. It tells that super-thin, three-inch disk ...
2
votes
1answer
341 views

Strength of Magnetic Field Around a Superconductor

I recently learned that the strength of a Magnetic field around a conductor is proportional to the current flowing in it. So if we have a Mercury wire at absolute zero and pass a current through it ...
10
votes
2answers
304 views

Superconductivity reasons (Intutitive)

Superconductivity I read in a book "Physics - Resnik and Halliday" the explanation of Type-I Superconductors{cold ones} that: The Electrons that make up current at super-cool temperatures move in ...
1
vote
2answers
139 views

Reference needed for Iron-based superconductors

Iron-based superconductor is a class of high-$T_c$ superconductors discovered in 2008. Are there any review papers about these superconductors yet? If not, which are the key papers in the field?
8
votes
3answers
631 views

Is a superconductor really a super conductor?

It is known that a superconductor is a material with electrical resistance zero. My question is, it is exactly zero, a theoretical zero, or for practical realistic reasons it is effectively zero?
2
votes
1answer
259 views

half Skyrmion vs Meron

Is there a difference between a half skyrmion and a meron? I'm asking this in regard to half skyrmion theories of High Tc Superconductors. It would be interresting to know if the proposed half ...
0
votes
1answer
111 views

Superconductors on each side of a flexible membrane what happens?

I have a sheet of flexible Kevlar 16th of an inch thick coated on each side with a high temperature superconductor, what happens when you put hundred amp of current into each side, and then 1000 and ...
0
votes
2answers
834 views

How can I measure the conductivity of a copper rod?

I would like to perform an experiment to measure the conductivity of a copper rod. What device can I use to perform to experiment? is there such a thing as a conductivity meter? All i found was an ...
3
votes
1answer
303 views

Effects of parallel superconducting plates

Assuming the existence of virtual particle field ( zero point energy field) Casimir force is produced by 2 parallel conducting plates excluding some of the frequencies between the plates, if these 2 ...
1
vote
1answer
207 views

Quantum Locking and gravity

Can a device be constructed of a super conducting disk connected to a electromagnet that generates a field such that the disc locks "in" the field generated by the electromagnet such that the device ...
10
votes
1answer
1k views

Has Chandra Varma explained cuprate superconductivity?

Chandra Varma is a theoretical physicist at University of California, Riverside. A couple years ago, he gave a talk at my institution purporting to explain superconductivity in the cuprates. It all ...
6
votes
2answers
316 views

Layman explanation for superconductivity?

I'm interested in reading an explanation of superconductivity, but though I have an undergraduate degree in engineering, I'm not sure I'm up to reading a detailed mathematical treatment of the theory. ...