1106.6193 (F. Palestini et al.)

Dispersions, weights, and widths of the single-particle spectral
function in the normal phase of a Fermi gas    [PDF]

F. Palestini, A. Perali, P. Pieri, G. C. Strinati

The dispersions, weights, and widths of the peaks of the single-particle
spectral function in the presence of pair correlations, for a Fermi gas with
either attractive or repulsive short-range inter-particle interaction, are
determined in the normal phase over a wide range of wave vectors, with a
twofold purpose. The first one is to determine how these dispersions identify
both an energy scale known as the pseudo-gap near the Fermi wave vector, as
well as an additional energy scale related to the contact C at large wave
vectors. The second one is to differentiate the behaviors of the repulsive gas
from the attractive one in terms of crossing versus avoided crossing of the
dispersions near the Fermi wave vector. An analogy will also be drawn between
the occurrence of the pseudo-gap physics in a Fermi gas subject to pair
fluctuations and the persistence of local spin waves in the normal phase of
magnetic materials.

View original: http://arxiv.org/abs/1106.6193