Spectral Functions and rf Response of Ultracold Fermionic Atoms

Understand

We present a calculation of the spectral functions and the associated rf response of ultracold fermionic atoms near a Feshbach resonance.

• The single particle spectra are peaked at energies that can be modeled by a modified BCS dispersion.
• However, even at very low temperatures their width is comparable to their energy, except for a small region around the dispersion minimum.
• The structure of the excitation spectrum of the unitary gas at infinite scattering length agrees with recent momentum-resolved rf spectra near the critical temperature.