Questions tagged [superconductivity]
Superconductivity is the transmission of current with no resistive losses, and is one of the most active areas of condensed matter physics research.
1,305
questions
1
vote
1
answer
30
views
What is nematic phase in superconductors
I've seen the picture of nematic phase in liquid crystals like this one
https://saylordotorg.github.io/text_general-chemistry-principles-patterns-and-applications-v1.0/s15-08-liquid-crystals.html, ...
- 99
1
vote
0
answers
32
views
Assuming vortex defect pinning is equal, and number of tubes are equal should longer flux tubes lead to stronger pinning?
Suppose you have two superconductors that resemble rectangular prisms with identical width and length. The first superconductor call it $A$ is shorter than $B$ visualized below:
Now both $A$ and $B$ ...
- 2,979
2
votes
5
answers
144
views
How would current be distributed among two parallel paths of zero resistance?
In an ideal circuit with two wires in parallel, if one path has zero resistance and another has a nonzero resistance, all of the charges will flow through the wire with zero resistance (if I ...
- 21
4
votes
1
answer
157
views
Inconsistency in microscopic derivation of the Josephson effect?
My question is related to, but different from, other questions in this platform (see this, this and this).
One of the few places I have found in literature that provide a microscopic derivation of the ...
- 1,540
1
vote
1
answer
50
views
If you embed an extremely thin magnetic strip in superconducting block do supercurrents form around the strip?
Given a superconducting block (lets assume type 1) in grey below and a very thin magnetic strip with a simple magnetic dipole structure (in blue below) inserted into the block. If we were to cool the ...
- 2,979
1
vote
0
answers
53
views
Physical meaning of the terms in the Mattis-Bardeen Integrals
Mattis-Bardeen Integrals
The Mattis-Bardeen integrals for the complex conductivity $\sigma = \sigma_1-j\sigma_2$ of a superconductor describe the electromagnetic response to a high frequency drive.
...
- 11
-1
votes
1
answer
102
views
How can I can solution to BCS gap eq. around critical point $T_c$?
The BCS gap equation is $$1=gn\int_0^{\Delta\epsilon} d\epsilon \frac{1}{\sqrt{\epsilon^2+\Delta^2}}\tanh\frac{\sqrt{\epsilon^2+\Delta^2}}{2kT}.$$ At the critical point, we have $\Delta=0$, therefore ...
- 3
0
votes
0
answers
41
views
Are there thermodynamic reasons a super diamagnet cannot exist?
We define a super diamagnet as a substance which not only expels any internal magnetic fields but actually produces a stronger internal magnetic field in the opposite direction of the external field, ...
- 2,979
1
vote
0
answers
41
views
Does electric charge have any effect on diamagnetism?
Diamagnetic materials repel magnetic fields because freely moving electrons or cooper pairs within the material can form eddy currents in response to a changing magnetic field.
It is natural to wonder ...
- 2,979
0
votes
0
answers
27
views
Current in a Superconducting Loop Interrupted by a Josephson Junction
Assuming we have the following circuit consisting of a superconducting loop having the same superconductor material everywhere, and interrupted by the short Josephson junction J1 with a phase ...
- 101
0
votes
0
answers
90
views
Anderson Higgs mechanism and superconducting phase fluctuations
In the context of superconductivity, in the Anderson Higgs mechanism (see, for instance, https://doi.org/10.1119/1.5093291 (PDF), or https://doi.org/10.21468/SciPostPhysLectNotes.11 (PDF), the gauge-...
2
votes
1
answer
73
views
Are there any known bulk superinsulators?
I recently learned about superinsulators. Basically materials which exhibit an abrupt phase transition to becoming perfectly resistive.
The wiki article reveals that this phenomenon is exhibited in ...
- 2,979
-1
votes
1
answer
74
views
How much liquid nitrogen is required for Maglev trains?
I understand magnets require cooling to achieve supermagnetivity. How much of liquid nitrogen do Maglevs carry with them? How much is required to keep them cool? What is liquid nitrogen consumption ...
- 1
2
votes
0
answers
40
views
Expansion of interaction potential in terms of spherical harmonics in unconventional superconductivity
I am currently reading the book Introduction to Unconventional Superconductivity by V. P. Mineev and K. V. Samokhin. In Equation (1.6), the interaction potential $V$ is expanded in terms of spherical ...
- 21
2
votes
0
answers
89
views
Josephson supercurrent measurement in a lab
This may be a very trivial question but I am a theoretician and can't find the answer to this question for the life of me. Is it possible to actually measure the Josephson supercurrent flowing through ...
- 155