All Questions
Tagged with symmetry-breaking superconductivity
31
questions
5
votes
2
answers
365
views
Why are there no Goldstone modes in superconductor?
Usually, the absence of Goldstone modes in a superconductor is seen as an example of the Anderson-Higgs mechanism, related to the fact that there is gauge invariance due to the electromagnetic gauge ...
- 109
2
votes
1
answer
97
views
Superconducting ground-state and Higgs mechanism
I found this article on spontaneous symmetry breaking in superconductors. Using the same arguments as Weinberg, the author demonstrates that the properties of a superconductor are the consequences of ...
- 172
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-...
3
votes
0
answers
44
views
Spectral function of superconductor in the BEC regime: how does Higgs mechanism affect the spectrum?
Consider the standard BCS theory but assume that the interaction energy $U$ that enters the definition of gap parameter (i.e. $\Delta = (U/N)\sum_k \langle c_{-k\downarrow} c_{k\uparrow} \rangle$, ...
- 3,014
0
votes
0
answers
77
views
Infinite conductivity, goldstone bosons and generalized voltage
Weinberg [1] has put forth an elegant argument (summarized in [2, Section 3.3] and at the bottom of the question), which suggests that the broken symmetry phase of any $U(1)$ gauge theory will be ...
- 169
1
vote
1
answer
38
views
How to experimentally distinguish Nematic transition versus Jahn-Teller distortion?
Both nematic transition and Jahn-Teller distortion distorts the lattice and reduces the symmetry of a crystal; both of the structure transition can take place at higher temperature than the magnetic ...
6
votes
3
answers
1k
views
Mermin-Wagner and superconductivity
Why can superconductivity exist in 2D since Mermin-Wagner should forbit it? This question was asked here before, but I don't think anyone gave a satisfactory answer, so let me revisit it.
I have read ...
- 2,113
4
votes
1
answer
379
views
Why is symmetry not spontaneously broken in superconductors?
Take the BCS model of superconductivity. We have creation and annihilation operators for the electron, $\Psi/\Psi^\dagger$, and the order parameter for the phase transition from the metallic phase ...
- 61
0
votes
1
answer
368
views
BCS theory without breaking symmetry?
I'm studying the analogies between the Higgs mechanism and superconductivity, specially, the BCS theory.
To develop the BCS theory, a mean field aproximation is done, which breaks the gauge invariance....
5
votes
1
answer
332
views
Why is the Mermin-Wanger theorem not considered for superconductors in 2D?
Several papers set up a model of fermions in 2D and calculate superconducting $T_c$, e.g.:
https://arxiv.org/abs/1808.08635
https://arxiv.org/abs/1406.1193
https://doi.org/10.1073/pnas.1620651114
...
- 151
1
vote
0
answers
256
views
Anderson-Higgs Mechanism
Consider an abelian gauge field coupled with a complex field:
$$\mathcal{L}=-\frac{1}{4}F_{\mu\nu}F^{\mu\nu}+(D\varphi)^\dagger D\varphi+\mu^2 \varphi^\dagger\varphi-\lambda(\varphi^\dagger\varphi)^2.$...
- 131
0
votes
1
answer
537
views
Why isn't superconductivity destroyed by the Goldstone modes?
In BCS theory they break particle number conservation and show the existence of a gap, which would explain why groundstate properties stay relatively the same even for higher temperatures (until beta ...
- 110
0
votes
1
answer
84
views
Rest frame of massive photon in Meissner–Ochsenfeld effect
The Meissner–Ochsenfeld effect together with spontaneous symmetry breaking and the London Equation yields
$(\Box+M^2)A^\mu=0$
and gives photon an effective mass
$q\sqrt{\frac{n_c}{m_c}}$
Which is ...
- 61
3
votes
0
answers
60
views
Metallic state in 2D
Mermin Wagner theorem prevents any spontaneous breaking of continuous symmetry for short ranged interactions for dimensions, D $\leq$2 for any finite temperature. So I understand that superconducting ...
- 667
0
votes
0
answers
108
views
How does phase gets aligned in a superconductor?
I am trying to make an analogy between the spontaneous symmetry breaking occurring in magnetism and that of superconducvity, but I am struggling to make it precise.
In magnetism, we know that ...
- 1,480