Abstract:

(I) Calibration of Interaction Energy between Bose and Fermi Superfluids. (arXiv: 1409.0282). In this job we study the interaction energy in a mixture of Bose and Fermi superfluids realized in recent cold atom experiment. On the Bose-Einstein-condensate (BEC) side of a Feshbach resonance between fermionic atoms, this interaction energy can be directly related to the scattering length between a bosonic atom and a dimer composed of fermions. We calculate the atom-dimer scattering length from a three-body analysis with both a zero-range model and a separable model including the van der Waals length scale, and we find significant deviation from the result given by a mean-field approach. We also find that the multiple scattering between atom and dimer can account for such a deviation. Our results provide a calibration to the mean-field interaction energy, which can be verified by measuring the shift of collective oscillation frequency.
(II) Effect of short-range interaction for collision of ultracold dipoles (arXiv: 1410.0545). In this job we consider the scattering of two ultracold polarized dipoles with both a short-range interaction (SRI) and a weak dipole-dipole interaction (DDI) which is far away from a shape-resonance. In previous works the scattering amplitude is usually calculated via 1st-order Born approximation. Our results show that significant derivation from this approximation can arise in some cases. In these cases the SRI can significantly modify the dipole-dipole scattering amplitude, even if the scattering amplitude for the SRI alone is negligibly smaller than the dipolar length of the DDI. We further obtain approximate analytical expressions for the inter-dipole scattering amplitude.
 
 
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