Absence of fermionic quasi-particles in the superfluid state of the attractive Fermi gas
Loading...
Date
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Description
We calculate the effect of order parameter fluctuations on the fermionic single-particle excitations in the superfluid state of neutral fermions interacting with short range attractive forces. We show that in dimensions D \leq 3 the singular effective interaction between the fermions mediated by the gapless Bogoliubov-Anderson mode prohibits the existence of well-defined quasi-particles. We explicitly calculate the single-particle spectral function in the BEC regime in D=3 and show that in this case the quasi-particle residue and the density of states are logarithmically suppressed.
4 RevTex pages, 3 figures; title changed, new Figure 1, added references. We argue that in the entire regime of the BCS-BEC crossover the quasi-particle picture breaks down in D <=3 for neutral fermions (but NOT for charged fermions)
4 RevTex pages, 3 figures; title changed, new Figure 1, added references. We argue that in the entire regime of the BCS-BEC crossover the quasi-particle picture breaks down in D <=3 for neutral fermions (but NOT for charged fermions)