| Popis: |
We revisit the old problem of exotic superconductivity as Cooper pairing with finite angular momentum emerging from a central potential.\ud Based on some general considerations, we suggest that the phenomenon\ud is associated with interactions that keep electrons at some particular,\ud finite distance r(0), and occurs at a range of intermediate densities\ud n similar to 1/r(0)(3). We discuss the ground state and the critical\ud temperature in the framework of a standard functional-integral theory\ud of the BCS to Bose crossover. We find that, due to the lower energy\ud of two-body bound states with l = 0, the rotational symmetry of the\ud ground state is always restored on approaching the Bose limit. Moreover\ud in that limit the critical temperature is always higher for pairs\ud with l = 0. The breaking of the rotational symmetry of the continuum\ud by the superfluid state thus seems to be a property of weakly-attractive,\ud non-monotonic interaction potentials, at intermediate densities. |
