REVIEWING SOME CURRENT THEORIES FOR HIGH-TEMPERATURE SUPERCONDUCTORS

In this article, some theories on the properties of high-critical-temp erature superconductors are briefly reviewed, with a special emphasis on those theories based on pairing by antiferromagnetic fluctuations a nd the resonating-valence-bond scenarios. Ideas linking the physics of the cuprates with those of the recently discovered ladder materials a re presented. Possible explanations for the spin gap in the high-criti cal-temperature materials using preformed pairs and stripes are briefl y discussed. The goal of this article is to provide simple explanation s for the main ideas and concepts, while keeping the mathematical and computational details to a minimum.