Absence of Fermionic Quasiparticles in the Superfluid State of the Attractive Fermi Gas
Abstract
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≤3 the singular effective interaction between the fermions mediated by the gapless Bogoliubov-Anderson mode prohibits the existence of well-defined quasiparticles. We explicitly calculate the single-particle spectral function in the BEC regime in D=3 and show that in this case the quasiparticle residue and the density of states are logarithmically suppressed.
- Publication:
-
Physical Review Letters
- Pub Date:
- February 2008
- DOI:
- 10.1103/PhysRevLett.100.050403
- arXiv:
- arXiv:0710.1801
- Bibcode:
- 2008PhRvL.100e0403L
- Keywords:
-
- 03.75.Ss;
- 03.75.Hh;
- 74.20.Fg;
- Degenerate Fermi gases;
- Static properties of condensates;
- thermodynamical statistical and structural properties;
- BCS theory and its development;
- Condensed Matter - Superconductivity;
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- 4 RevTex pages, 3 figures