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
60
votes
2
answers
27k
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 ...
- 691
38
votes
3
answers
2k
views
Why is high temperature superconductivity so hard to solve?
The phenomenon of high temperature superconductivity has been known for decades, particularly layered cuprate superconductors. We know the precise lattice structure of the materials. We know the band ...
- 381
36
votes
2
answers
4k
views
Should a superconductor act as a perfect mirror?
I have been told that metals are good reflectors because they are good conductors. Since an electric field in conductors cause the electrons to move until they cancel out the field, there really can'...
- 912
33
votes
6
answers
23k
views
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 ...
- 948
27
votes
6
answers
8k
views
Why don't superconductors, which have zero electrical resistance, violate the second law of thermodynamics?
There are bunch of questions on here asking whether superconductors really have exactly zero resistance and answers saying they do. My question is how this doesn't violate the second law of ...
- 2,327
27
votes
4
answers
8k
views
Are room temperature superconductors theoretically possible, and through what mechanism?
At the moment, the highest critical temperature superconductor known to science (or myself, at least) is mercury barium calcium copper oxide. With a $T_{c}$ of roughly 133 K, that's well above the ...
- 2,714
26
votes
2
answers
3k
views
Do topological superconductors exhibit symmetry-enriched topological order?
Gapped Hamiltonians with a ground-state having long-range entanglement (LRE), are said to have topological order (TO), while if the ground state is short-range entangled (SRE) they are in the trivial ...
- 5,382
26
votes
3
answers
1k
views
Why is there a band structure for strongly correlated systems?
The existence of band structure of a crystalline solid comes from the Bloch theorem, which relies on the independent-electron approximation. Why do people still talk about the band structure for a ...
- 414
25
votes
2
answers
2k
views
Is an electron a superconductor?
A superconductor has zero resistance. What about an electron in a vacuum? Could this simple system be considered superconducting?
- 6,015
23
votes
3
answers
7k
views
Mean field equations in the BCS theory of superconductivity
In BCS theory, one takes the model Hamiltonian
$$
\sum_{k\sigma} (E_k-\mu)c_{k\sigma}^\dagger c_{k\sigma} +\sum_{kk'}V_{kk'}c_{k\uparrow}^\dagger c_{-k\downarrow}^\dagger c_{-k'\downarrow} c_{k'\...
- 8,160
22
votes
4
answers
14k
views
What makes a superconductor topological?
I have read a fair bit about topological insulators and proximity induced Majorana bound states when placing a superconductor in proximity to a topological insulator.
I've also read a bit about ...
- 373
22
votes
5
answers
4k
views
What is the link between the BCS ground state and superconductivity?
The link between the BCS ground state
$$
\left|\Psi_\mathrm{BCS}\right\rangle = \prod_k \left( u_k - v_ke^{i \phi} c_{k\uparrow}^{\dagger} c_{-k\downarrow}^{\dagger}\right) \left|0\right\rangle
$$
and ...
- 1,480
22
votes
4
answers
2k
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 ...
- 13.2k
21
votes
3
answers
14k
views
Can a superconducting wire conduct unlimited current?
A superconducting wire has no electrical resistance and as such it does not heat up when current passes through it. Non-superconducting wires can be damaged by too much current, because they get too ...
- 3,197
20
votes
1
answer
9k
views
Superconductor symmetry breaking
When water freezes continuous translational symmetry is broken. When a metal becomes superconducting, what is the symmetry that gets broken?
- 606