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No perfect conductors exist. Some materials *approach* the definition. But light gray isn't white, and an *almost perfect* conductor isn't a perfect conductor. —Preceding unsigned comment added by 75.13.228.32 (talk) 23:26, 2 October 2007 (UTC)Reply

Arrrgh! The last edit by Art Carlson is useful but is also a good example of why I called the page classical superconductor in the first place. That term is used, e.g., in the textbooks of Jackson, Griffiths, and Wheeler to distinguish between the classical limit of zero resistivity and the general case of zero resistivity. Ordinary superconductors exhibit zero resistivity (and hence are perfect conductors), but also many quantum mechanical effects (of which the Meissner effect is one). Classical superconductors don't have physical reality but are useful for modeling (as perfect conductors with no other special properties).

When the page got renamed "perfect conductor" I groaned but decided to wait and see what happened -- but, sadly, we still need a "classical superconductor" page. zowie 20:23, 20 September 2005 (UTC)Reply

Do we need this page at all? There are only two links to perfect conductor and none at all to classical superconductor. I think the information here (what little there is) should be incorporated into superconductivity.

I don't know how Jackson, Griffiths, and Wheeler use the term, but a quick google of "classical superconductor" seems to indicate that it is more commonly used in contrast to HTSC.

--Art Carlson 07:26, 21 September 2005 (UTC)Reply

I actually wrote both the classical superconductor stub and the two references to it (I worked on both pages around the same time and noticed that each would benefit from a link to a classical superconductor page...) -- but they were renamed to "perfect conductor" after the fact. I don't especially think that we need a "perfect conductor" page. We may not even need a "classical superconductor" page, but it's a nice contrast to actual superconductors, which have quite surprising properties (the second most obvious, after the Meissner effect, is the quantization of magnetic flux through closed loops of superconductor). On the other hand, classical electron radius is similarly abstruse but exists... zowie 18:37, 21 September 2005 (UTC)Reply

Not having heard back, I went ahead and made classical superconductor a disambiguator, and also added references to the ambiguity here to this page. zowie 18:01, 27 September 2005 (UTC)Reply

Fine! I replaced the links to superconductivity with links to conventional superconductor. _R_ 17:18, 28 September 2005 (UTC)Reply

Thanks, Rorro. I feel much better now. :-) zowie 19:58, 28 September 2005 (UTC)Reply

I think there's something important missing here. It is a well known result in quantum mechanics that electrons in the periodic potential of the ions in a solid (see bloch wave) move with a constant mean velocity if the lattice is perfect, this is, for a perfect lattice the resistance is strictly zero. Resistance happens in real world because of temperature, which distorts the lattice, and defects, vacancies... (neglecting interactions). This is what I would call a perfect conductor, and it is not a superconductor in the sense of Cooper pairing. I don't quite get what a "classical superconductor is", both perfect conductivity and superconductivity are intrinsically quantum mechanical. (Although it is true that some people call classical to the ordinary superconductivity as opposed to high-Tc) --El perseguidor 00:57, 26 July 2007 (UTC)Reply

Is the ratings bar actually wikimedia legit? --86.29.233.192 (talk) 06:30, 12 May 2011 (UTC)Reply