TY - JOUR
A2 - Reshak, Ali Hussain
AU - Zinner, N. T.
PY - 2012
DA - 2012/08/01
TI - Effective Potential for Ultracold Atoms at the Zero Crossing of a Feshbach Resonance
SP - 241051
VL - 2012
AB - We consider finite-range effects when the scattering length goes to zero near a magnetically controlledFeshbach resonance. The traditional effective-range expansion is badly behaved at this point,and we therefore introduce an effective potential that reproduces the full T-matrix. To lowest orderthe effective potential goes as momentum squared times a factor that is well defined as the scatteringlength goes to zero. The potential turns out to be proportional to the background scatteringlength squared times the background effective range for the resonance. We proceed to estimate the applicability and relative importance of this potential for Bose-Einstein condensatesand for two-component Fermi gaseswhere the attractive nature of the effective potential can lead to collapse above a critical particle numberor induce instability toward pairing and superfluidity. For broad Feshbach resonances the higher order effect iscompletely negligible. However, for narrow resonances in tightly confined samples signatures might beexperimentally accessible. This could be relevant for suboptical wavelength microstructured trapsat the interface of cold atoms and solid-state surfaces.
SN - 2314-8039
UR - https://doi.org/10.1155/2012/241051
DO - 10.1155/2012/241051
JF - Journal of Atomic, Molecular, and Optical Physics
PB - Hindawi Publishing Corporation
KW -
ER -