2004/09/14 by T. Domański, T. Domanski, J. Ranninger
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Coupling (piping) #Fermion #Feshbach resonance #Pairing #Phase (matter) #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Quantum, superfluid, helium dynamics #Quasiparticle #Resonance (particle physics) #Superconductivity #Superfluidity #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.70.184513
published as Phys. Rev. B 70, 184513 (2004). · 5 pages, 3 figures; to appear in Phys Rev B
arxiv created 2004/09/14 · openalex publication_date 2004/11/16 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The signature of superfluidity in bosonic systems is a sound-wave-like spectrum of the single particle excitations which in the case of strong interactions is roughly temperature independent. In Fermionic systems, where Fermion pairing arises as a resonance phenomenon between free Fermions and paired Fermionic states (examples are: the atomic gases of 6Li or 40K controlled by a Feshbach resonance, polaronic systems in the intermediary coupling regime, d-wave hole pairing in the strongly correlated Hubbard system), remnants of such superfluid characteristics are expected to be visible in the normal state. The single particle excitations maintain a sound-wave-like structure for wave vectors above a certain qmin(T) where they practically coincide there with the spectrum of the superfluid phase for T<Tc. Upon approaching the transition from above this region in q space extends down to small momenta, except for a narrow region around q=0 where such modes change into damped free particle like excitations.