6533b822fe1ef96bd127d984

RESEARCH PRODUCT

Signatures of superfluidity for Feshbach-resonant Fermi gases

Päivi TörmäMirta RodriguezJami J. Kinnunen

subject

PhysicsCondensed Matter::Quantum GasesCondensed matter physicsStrongly Correlated Electrons (cond-mat.str-el)Condensed Matter::Othermedia_common.quotation_subjectGeneral Physics and AstronomyFOS: Physical sciencesBCS theoryAsymmetrylaw.inventionSuperfluidityCondensed Matter - Strongly Correlated ElectronslawPseudogapFeshbach resonanceFermi gasExcitationBose–Einstein condensatemedia_common

description

We consider atomic Fermi gases where Feshbach resonances can be used to continuously tune the system from weak to strong interaction regime, allowing to scan the whole BCS-BEC crossover. We show how a probing field transferring atoms out of the superfluid can be used to detect the onset of the superfluid transition in the high-$T_c$ and BCS regimes. The number of transferred atoms, as a function of the energy given by the probing field, peaks at the gap energy. The shape of the peak is asymmetric due to the single particle excitation gap. Since the excitation gap includes also a pseudogap contribution, the asymmetry alone is not a signature of superfluidity. Incoherent nature of the non-condensed pairs leads to broadening of the peak. The pseudogap and therefore the broadening decay below the critical temperature, causing a drastic increase in the asymmetry. This provides a signature of the transition.

yearjournalcountryeditionlanguage
2004-01-27
https://dx.doi.org/10.48550/arxiv.cond-mat/0401543