The Bose-Einstein condensation (BEC) temperature $T_{ c}$ of Cooper pairs (CPs) created from a very general interfermion interaction is determined for a { \it linear}, as well as the usual quadratic, energy { \it vs}% center-of-mass momentum dispersion relation. This $T_{ c}$ is then compared to that of Wen & Kan (1988) in $d=2+\epsilon $ dimensions, for small $\epsilon $, in a geometry of an infinite stack of parallel (e.g., copper-oxygen) planes as in a cuprate, and with a new result for linear-dispersion CPs. This allows addressing, as a rough first approximation, superconductivity for any $d>1$.
Categories: cond-mat.supr-con