Kohn-Sham approach to Fermi gas superfluidity: the bilayer of fermionic polar molecules

Abstract

By using a well established 'ab initio' theoretical approach developed in the past to quantitatively study the superconductivity of condensed matter systems, which is based on the Kohn-Sham Density Functional theory, I study the superfluid properties and the BCS-BEC crossover of two parallel bi-dimensional layers of fermionic dipolar molecules, where the pairing mechanism leading to superfluidity is provided by the inter-layer coupling between dipoles. The finite temperature superfluid properties of both the homogeneous system and one were the fermions in each layer are confined by a square optical lattice are studied at half filling conditions, and for different values of the strength of the confining optical potential. The T=0 results for the homogeneous system are found to be in excellent agreement with Diffusion Monte Carlo results. The superfluid transition temperature in the BCS region is found to increase, for a given inter-layer coupling, with the strength of the confining optical potential. A transition occurs at sufficiently small interlayer distances, where the fermions becomes localized within the optical lattice sites in a square geometry with an increased effective lattice constant, forming a system of localized composite bosons. This transition should be signalled by a sudden drop in the superfluid fraction of the system.

10 pages, 10 figures (accepted for publication in Phys. Rev. A)

References in corpus (12)

• Theory of ultracold Fermi gases
• Ultracold Dipolar Gas of Fermionic ${}^{23}$Na${}^{40}$K Molecules in their Absolute Ground State
• Stable Topological Superfluid Phase of Ultracold Polar Fermionic Molecules
• Local Density Functional Theory for Superfluid Fermionic Systems: The Unitary Gas
• Quantum phases of a Two-Dimensional Dipolar Fermi Gas
• Interaction-controlled transport of an ultracold Fermi gas
• Interlayer superfluidity in bilayer systems of fermionic polar molecules
• Two-dimensional scattering and bound states of polar molecules in bilayers
• Superfluidity and dimerization in a multilayered system of fermionic polar molecules
• Fixed-node diffusion Monte Carlo study of the BCS-BEC crossover in a bilayer system of fermionic dipoles
• Unconventional symmetries of Fermi liquid and Cooper pairing properties with electric and magnetic dipolar fermions
• Density functional theory of a trapped Bose gas with tunable scattering length: from weak-coupling to unitarity

Cited by in corpus (3)

• Supersolid phases of dipolar fermions in a two-dimensional-lattice bilayer array
• Out-of-equilibrium dynamics of repulsive Fermi gases in quasi-periodic potentials: a Density Functional Theory study
• Density functional theory versus quantum Monte Carlo simulations of Fermi gases in the optical-lattice arena