Pairing gap and in-gap excitations in trapped fermionic superfluids.
We consider trapped atomic Fermi gases with Feshbach-resonance enhanced interactions in pseudogap and superfluid temperatures. We calculate the spectrum of radio-frequency (or laser) excitations for transitions that transfer atoms out of the superfluid state. The spectrum displays the pairing gap and also the contribution of unpaired atoms, that is, in-gap excitations. The results support the conclusion that a superfluid, in which pairing is a manybody effect, was observed in recent experiments on radio-frequency spectroscopy of the pairing gap.
Department of Physics, NanoScience Center, Post Office Box 35, FIN-40014, University of Jyväskylä, Finland.
J
J
Kinnunen
M
M
Rodríguez
P
P
Törmä