Achieving higher superfluid transition Tc in atomic Fermi gases using mixed dimensionality

Achieving a higher superfluid transition Tc has been a goal for the fields of superconductivty and atomic Fermi gases. In this talk, I will present a study on the exotic superfluid and pairing phenomena in two component atomic Fermi gases in mixed dimensions, where one component feels a regular 3D continuum space, while the other is subject to a 1D optic lattice potential. Via tuning the lattice spacing and depth, one can manipulate the effective dimensionality of the lattice component from quasi-3D to quasi-1D. I shall use a pairing fluctuation theory to address the pairing phenomena beyond BCS mean-field approximations; when the interaction is strong, pairing fluctuations lead to a pseudogap and necessarily suppress Tc from its mean-field solution. In addition to the exotic pairing phenomena caused by Fermi surface mismatch, here we show that one can tune the shape of the Fermi surface of the lattice component such that the maximum Tc attainable in such a system well surpasses that in an ordinary 3D Fermi gas, making the superfluid phase easier to access experimentally.


References:

L.F. Zhang, Y.M. Che, J.B. Wang, & Q.J. Chen, Sci. Rep. 7, 12948 (2017).