Can Cooper Pairs Be Explained Through the Casimir Effect?

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Discussion Overview

The discussion centers around the question of whether Cooper pairs can be explained through the Casimir effect, exploring theoretical aspects of superconductivity, phase transitions, and the nature of electron interactions in superconductors.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants assert that Cooper pairs are primarily bound by phonons, particularly in conventional superconductors.
  • Others argue that the Casimir effect is too weak to account for the coupling strength observed in superconductors, including high-Tc cuprates.
  • A participant introduces the idea of a phase transition related to resistivity, suggesting that a small number of unpaired electrons can lead to a sudden increase in resistivity.
  • Another participant questions the relevance of phase transitions to the behavior of individual electrons, emphasizing that phase transitions involve collective behavior rather than isolated particles.
  • One participant notes that the transition region can be influenced by factors such as impurities and crystalline order, suggesting that the transition is not solely dependent on electrical transport measurements.

Areas of Agreement / Disagreement

Participants express differing views on the role of the Casimir effect in explaining Cooper pairs, with no consensus reached on the relationship between phase transitions and resistivity in superconductors.

Contextual Notes

Participants highlight the complexity of phase transitions and the influence of material properties on superconducting behavior, indicating that assumptions about electron interactions and transition mechanisms may vary significantly.

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Just a general question, can cooper pairs be explained using the casimir effect?
 
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No - Cooper pairs are bound by phonons.
 
Vanadium 50 said:
No - Cooper pairs are bound by phonons.

... in conventional superconductors.

Casimir effect is extremely weak! No way can it form such coupling strength we see not only in conventional superconductors, but also high-Tc cuprates. Besides, there's no explanation for it to suddenly kick in at Tc via a phase transition-like phenomenon.

Zz.
 
Phase transition and sudden kick:

Well, if you say that resistivity appears as soon as 1 electron in 10.000 is unpaired or hot or out-of-crystalline-order or any other effect, then you get a very sudden kick from any kind of transition that would be smooth for each single electron, like a standard Fermi statistics.

In other words, the probability of an electron being at 5+ sigma is MUCH lower than at 5 sigma. This slope is steeper at 5 sigma than at 1 sigma.

Within such an explanation, the transition energy for a single electron (or a pair if you prefer, this is a separate question) must be several times higher than the superconductor's critical temperature.

I strongly believe this is the fundamental reason for resistivity to appear so brutally over a narrow temperature span.
 
Enthalpy said:
In other words, the probability of an electron being at 5+ sigma is MUCH lower than at 5 sigma. This slope is steeper at 5 sigma than at 1 sigma.

True, but I don't think this has anything to do with a phase transition. What would be the order parameter?
 
Enthalpy said:
Phase transition and sudden kick:

Well, if you say that resistivity appears as soon as 1 electron in 10.000 is unpaired or hot or out-of-crystalline-order or any other effect, then you get a very sudden kick from any kind of transition that would be smooth for each single electron, like a standard Fermi statistics.

In other words, the probability of an electron being at 5+ sigma is MUCH lower than at 5 sigma. This slope is steeper at 5 sigma than at 1 sigma.

Within such an explanation, the transition energy for a single electron (or a pair if you prefer, this is a separate question) must be several times higher than the superconductor's critical temperature.

I strongly believe this is the fundamental reason for resistivity to appear so brutally over a narrow temperature span.

Er.. a "phase transition" is a collective behavior, not the behavior of "one electron". This is certainly true for a superconductor. You can't have just one electron (or two, or three, etc) undergoing such a transition.

The rest of your post, I don't understand. Note that I can make the width of the transition region change by changing either the impurity of the material, the crystalline order of the material, putting magnetic atoms, etc. Not only that, the transition region here also in the magnetic susceptibility measurement, which is a more stringent test of a superconductor than simply the resistivity measurement. So it isn't just a matter of electrical transport transition.

Zz.
 

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