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.
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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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Why do superconductors conduct electricity without resistance?
Many authors have suggested that persistent currents in superconducting rings arise from the energy gap in the single-particle spectrum. Indeed, the argument has been put forward many times on this ...
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Group Theory of Superconducting Order Parameters?
In crystalline superconductors, the order parameter $\Delta(\mathbf{k})$ (aka gap, or Cooper pair wavefunction) can be classified by its symmetry according to the representations of the symmetry group ...
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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 ...
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Nambu-Goldstone bosons from a quantum anomaly symmetry breaking?
We know that:
Nambu-Goldstone bosons come from Goldstone theorem: a spontaneous (continuous)-symmetry breaking of the system leads to massless scalar modes.
quantum anomaly: is the anomalous ...
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Experimental signature of topological superconductor
I was wondering if someone can provides some clear experimental signatures of a topological superconductors ?
I was thinking about that, because for topological insulator, one of the hallmarks is ...
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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?
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BCS-BEC crossover
It would be really helpful if somebody could describe what does one mean by a BEC-BCS Crossover. I was going through articles available on the topic, but I was unable to grasp the gist of the topic.
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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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Why superconductors aren't used in space?
As we all know temperature of space is near to absolute zero.Then why super conductors aren't used there?
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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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How to derive that resistivity is zero from the BCS theory?
The conventional superconductors can be explained using the BCS theory. Usually, the BCS theory is introduced as follows:
We would like to consider the Hamiltonian that describes the system of ...
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Monopoles and the magnetic Higgs mechanism
In a paper of 't Hooft about the rôle of magnetic monopoles for a model of quark confinement, I don't understand the following sentence (end at paragraph 14)
[...] in order for monopoles to produce ...
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How is the superconducting coherence length measured experimentally?
In a superconductor, the coherence length is the mean distance between two electrons in a Cooper pair. How is the coherence length experimentally measured?
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How is Meissner effect explained by BCS theory?
Someone says we can derive the GL equations from BCS theory, which can explain Meissner effect, but I want a more clear physical picture of this phenomena.
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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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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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Why are Cooper pairs formed by electrons of opposite momentum and spin?
I understand that Cooper pair in low-temperature superconductivity are formed by electron-phonon interaction. Normally one then assumes that electrons of opposite momentum and spin are paired. This is ...
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To what extent can the superconducting order parameter be thought of as a macroscopic wavefunction?
I know that the order parameter does not obey the Schrodinger equation; it instead obeys the Ginzburg-Landau equation. However, I am unclear as to the situations under which the view of the ...
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Why don't we have a "Cooper pair" of two holes in a superconductor?
The condensate of Cooper pairs is described by a complex scalar field (or the order parameter) which, when quantized can give rise (or is capable of creating) two types of quanta with charges opposite ...
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Feshbach resonance in simple terms
I was reading up Feshbach resonances in cold atoms and I was unable to grasp the concept. I will tell you what I have understood. We consider two body scattering processes elastic as well as inelastic....
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What is the boundary condition for Ginzburg Landau equation?
I am trying to do some numerical calculation with Ginzburg-Landau (GL) equation for a superconductor. However, I am confused about the boundary condition of the GL equation.
If we introduce the GL ...
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Composite fields and statistics
The usual explanation for superconductivity is that the electrons form Cooper pairs, which are bosons. This effective boson then condenses. E.g., quoting Wikipedia,
Therefore, unlike electrons, ...
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Can neutrons detect the diamagnetic effects of superconductivity?
It is well known that an applied magnetic field to a superconducting material produces a diamagnetic response due to the induced screening currents.
Neutrons used as a probe for magnetism and crystal ...
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TQFT's as effective theories of the groundstate subspace
I often hear: "The degenerate groundstate subspace of a QFT is often a TQFT".
I'm trying to work out an example of this for, say, superconductors: In the context of condensed matter physics, the ...
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Synthesis of Fe-based superconductors
Polycrystal cuprate superconductors are generally prepared by solid state reactions: Starting reagents are in powder form, they are mixed to each other and placed into furnace on high temperature (...
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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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If a superconductor 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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How is stable levitation possible?
This question is with reference to the video in this blog post: http://www.universetoday.com/90183/quantum-levitation-and-the-superconductor/
My question is the following: how is the disc stable in ...
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Why don't low frequency phonons scatter electrons in a superconductor?
A crystal at any finite temperature has phonons, as longer wavelength phonons require less energy to be excited. It seems that the electron (or cooper pair composite particle) wave would be scattered ...
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