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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Interaction strength in BCS theory
I'm looking to plot the band gap $\Delta(T)$ as a function of temperature between $T = 0$ and $T = T_c$ by numerical evaluation of the band gap equation
$$\frac{1}{\mathcal{N}(0)V} = ...
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45 views
Superconductivity [duplicate]
What is the correct explanation of why superconductivity occurs in metals when they are cooled to a temperature below $T_c$?
My textbook has the following explanation:
Superconductivity is the ...
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41 views
Some questions about the edge states for time-reversal invariant topological superconductors?
Stimulated by my some recent calculations on edge states(ES) for time-reversal invariant(TRI) topological superconductors(TS) as well as many questions concerning the "edge states" in Physics ...
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1answer
70 views
Ginzburg-Landau model for superconductivity
Could someone kindly elaborate more on the Simple Interpretation section from this Wikipedia Article? I refer to the part on the natures of $\alpha , \beta$. Why can one assume that ...
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67 views
What is the importance of the Fermi energy $E_F$ or the chem. potential $\mu$ for topological superconductors
A lot of effort is put into shifting the Fermi energy of a topological insulator to exactly zero which then provides some advantages when this TI is coupled with a superconductor.
I don't understand ...
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How can Ohm's law be correct if superconductors have 0 resistivity
Ohm's law states that the relationship between current ( I ) voltage ( V ) and resistance ( R ) is
$$I = \frac{V}{R}$$
However superconductors cause the resistance of a material to go to zero, and ...
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Alternative to Cooper pairing in superconductivity
BCS theory, in which electrons form Cooper pairs, has been successful in explaining conventional superconductivity. Physicists have adopted similar pairing mechanism in an attempt to explain ...
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How is a Majorana fermion created when a s-wave superconductors is in proximity to a topological insulator (e.g. via an antidot)
Kane and Fu proposed a few geometries how to create Majorana zero modes using a s-wave superconductor in proximity to a 3D topological insulator (TI).
-> ...
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1answer
93 views
What is a $p_x + i p_y$ superconductor? Relation to topological superconductors
I often read about s-wave and p-wave superconductors. In particular a $p_x + i p_y$
superconductor - often mentioned in combination with topological superconductors.
I understand that the overall ...
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1answer
76 views
Electrical energy storage in superconductors
I am a first year A-level student and I am doing a project about the possibility of storing electrical energy in a superconductor. I have researched and I am aware of the critical current density and ...
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1answer
56 views
What is paramagnetic current-current correlation?
I know what paramagnetism is. But first I want to know about the paramagnetic current and then the above-mentioned correlation?
Actually, I am working on a paper on superconductivity where I have ...
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1answer
152 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 ...
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155 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. ...
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What is the “BCS Cooper pair condensation” as a physical phenomenon in terms of experiments?
"Thought" experiments and "numerical" experiments are allowed.
This question is motivated by the question Has BCS Cooper pair condensate been observed in experiment? ,
and by our recent research on ...
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1answer
88 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 we theoretical (i.e. BCS) some things just slipped ...
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75 views
Superconductors for sale? [closed]
Does anyone know where I can purchase superconductors for a school presentation? I don't need a whole kit, just the disk itself. Thanks.
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42 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 ...
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3answers
183 views
Induction cooker + superconductive pot
What will happen if I put a super-conductive object on an induction cooker, and turn the cooker on?
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2answers
129 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 ...
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1answer
161 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?
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227 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 ...
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77 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 ...
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38 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 ...
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1answer
42 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 ...
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2answers
247 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 ...
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2answers
198 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 ...
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40 views
How fast is an anti-quench?
Is there any evidence it is slower than a quench?
The rapid, energy-rich return of a superconducting electromagnet to the normal state is called a quench, and occurs very rapidly, perhaps almost ...
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281 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? ...
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547 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 ...
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1answer
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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 ...
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2answers
162 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 ...
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4answers
142 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 ...
4
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1answer
237 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 ...
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1answer
77 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?
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2answers
159 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 ...
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272 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?
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1answer
115 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 ...
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3answers
184 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?
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2answers
185 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 ...
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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 ...
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1answer
155 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 ...
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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? ...
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2answers
364 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?
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4answers
194 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 ...
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3answers
254 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. ...
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1answer
123 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. ...
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56 views
Should we expect reliable nano-particle engines within the next 5 years?
"Regarding engines" what are the current theories and examples of ongoing progress in nanoparticles?
References:
National Nanotechnology Initiative
electric motor made from one molecule 18 atoms
...
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1answer
174 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 = ...
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4answers
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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?
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2answers
653 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 ...
