Volume 116, Number 3, November 2016
|Number of page(s)||5|
|Section||Condensed Matter: Structural, Mechanical and Thermal Properties|
|Published online||19 December 2016|
Interplay of the pseudogap and the BCS gap for heteropairs in 40K-6Li mixture
1 Faculty of Mathematics and Physics, Charles University - Ke Karlovu 3, 12116 Prague 2, Czech Republic
2 Department of Quantum Matter Physics, University of Geneva - 24 quai Ernest-Ansermet, 1211 Geneva, Switzerland
Received: 21 September 2016
Accepted: 24 November 2016
The description of heteropairs like 40K-6Li near and in the superconducting state requires a fully self-consistent theory (see Hanai R. and Ohashi Y., Phys. Rev. A, 90 (2014) 043622). We derive analytic pseudogap Green's functions for the “normal” and superconducting states from the Luttinger-Ward theory with the T-matrix in the static separable approximation. The self-consistency in the closing loop of self-energy has two pronounced effects on the single-particle spectrum. First, the single-particle excitations decay before the asymptotic quasiparticle propagation is established, therefore the normal state is not a Fermi liquid. Second, the pseudogap has a V shape even for s-wave pairing. The V-shaped pseudogap and the U-shaped BCS gap interfere resulting in slope breaks of the gap walls and the in-gap states in the density of states. Various consequences of an incomplete self-consistency are demonstrated.
PACS: 67.85.-d – Ultracold gases, trapped gases / 67.85.Lm – Degenerate Fermi gases / 05.30.Fk – Fermion systems and electron gas
© EPLA, 2016
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