A survey on the crossover from BCS superconductivity to Bose-Einstein condensation

The BCS superconducting instability of a Fermi system (due to an attractive interparticle interaction) and the Bose-Einstein condensation of bosons be low a critical temperature can be bridged by following the continuous evolu tion between the two (BCS and Bose-Einstein) limits as the strength of the attractive fermion interaction is increased. In addition to being of specif ic interest for high-temperature (cuprate) superconductors, a theoretical s tudy of this evolution leads to a deeper understanding of the phenomenon of superconductivity per se. This paper provides a survey of the main ideas a nd results obtained in this field, with emphasis on the perspectives for fu ture research.