Why does superconductors don't radiate?

Thread starter Demystifier
Start date Mar 13, 2013
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Superconductors

In summary, in ordinary conductors, electrons can lose energy through two mechanisms: scattering on atoms in the lattice bulk, and by emitting electromagnetic radiation through acceleration. However, in superconductors, the presence of an energy gap prevents the first mechanism, but it is unclear if it also prevents the second mechanism. Some argue that the motion of Cooper pairs can be considered as a collective motion, which may explain the absence of radiation. Others suggest that the photon acquiring mass in superconductors could also explain the lack of radiation. It is also worth noting that the creation of a sustained supercurrent is through magnetic induction, not by applying an external electric field. There may also be a connection between superconductors and the Higgs mechanism in particle physics.

Mar 15, 2013

Demystifier

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DrDu said:

I also think that the original question has been clarified:
1. For a constant macroscopic current - whether superconducting or not - we expect practically no radiation due to the homogeneity of the charge and current distributions.
2. Radiation in superconductors is supressed further by a similar mechanism as scattering, i.e.
a Cooper pair can't make an energetically favourable radiative transition to a condensate with lower velocity as this condensate is not present.

As far as I am concerned, 1. is now sufficient to me.

<h2>1. Why do superconductors have no electrical resistance?</h2><p>Superconductors have no electrical resistance because they are able to conduct electricity with zero resistance when cooled below a certain temperature, known as the critical temperature. This is due to the phenomenon of electron pairing, where electrons in a superconductor form pairs and move through the material without any resistance.</p><h2>2. How do superconductors maintain their zero resistance?</h2><p>Superconductors maintain their zero resistance because of the Meissner effect, where they expel any magnetic fields that try to penetrate the material. This allows the electrons to continue moving without any interference, resulting in no electrical resistance.</p><h2>3. Why do superconductors not radiate heat?</h2><p>Superconductors do not radiate heat because they have perfect thermal conductivity, meaning they can transfer heat without any loss. This is due to the fact that electrons in a superconductor can move freely without any resistance, allowing them to carry heat without any loss of energy.</p><h2>4. What causes superconductors to lose their superconductivity?</h2><p>Superconductors can lose their superconductivity if they are exposed to temperatures above their critical temperature, or if they are subjected to strong magnetic fields. This disrupts the electron pairing and causes resistance to form, resulting in a loss of superconductivity.</p><h2>5. How are superconductors used in real-world applications?</h2><p>Superconductors are used in a variety of real-world applications, including in medical imaging devices such as MRI machines, in particle accelerators, and in power transmission lines to reduce energy loss. They are also being researched for use in quantum computing and levitating trains.</p>

1. Why do superconductors have no electrical resistance?

Superconductors have no electrical resistance because they are able to conduct electricity with zero resistance when cooled below a certain temperature, known as the critical temperature. This is due to the phenomenon of electron pairing, where electrons in a superconductor form pairs and move through the material without any resistance.

2. How do superconductors maintain their zero resistance?

Superconductors maintain their zero resistance because of the Meissner effect, where they expel any magnetic fields that try to penetrate the material. This allows the electrons to continue moving without any interference, resulting in no electrical resistance.

3. Why do superconductors not radiate heat?

Superconductors do not radiate heat because they have perfect thermal conductivity, meaning they can transfer heat without any loss. This is due to the fact that electrons in a superconductor can move freely without any resistance, allowing them to carry heat without any loss of energy.

4. What causes superconductors to lose their superconductivity?

Superconductors can lose their superconductivity if they are exposed to temperatures above their critical temperature, or if they are subjected to strong magnetic fields. This disrupts the electron pairing and causes resistance to form, resulting in a loss of superconductivity.

5. How are superconductors used in real-world applications?

Superconductors are used in a variety of real-world applications, including in medical imaging devices such as MRI machines, in particle accelerators, and in power transmission lines to reduce energy loss. They are also being researched for use in quantum computing and levitating trains.