Speaker
Giancarlo Calvanese-Strinati
Description
Temperature dependence of the pair coherence and healing
lengths for a fermionic superfluid throughout the BCS-BEC
crossover
The pair correlation function and the order parameter
correlation function probe, respectively, the intra-pair and
inter-pair correlations of a Fermi gas with attractive
inter-particle interaction. Here, these correlation
functions are
calculated in terms of a diagrammatic approach, as a
function of coupling throughout the BCS-BEC crossover and of
temperature, both in the superfluid and normal phase across
the critical temperature $T_{c}$. Several physical
quantities are obtained from this calculation, including the
pair coherence and healing lengths, the Tan's contact, the
crossover temperature $T^{*}$ below which inter-pair
correlations begin to build up in the normal phase, and the
signature for the disappearance of the underlying Fermi
surface which tends to survive in spite of pairing
correlations. A connection is also established with
experimental data on the temperature dependence of the
normal coherence length as extracted from the proximity
effect measured in high-temperature (cuprate) superconductors.
