Collective modes, stability and superfluid transition of a quasi-two-dimensional dipolar Fermi gas

Abstract

We examine collective modes, stability, and BCS pairing in a quasi-two-dimensional gas of dipolar fermions aligned by an external field. By using the (conserving) Hartree-Fock approximation, which treats direct and exchange interactions on an equal footing, we obtain the spectrum of single-particle excitations and long wavelength collective modes (zero sound) in the normal phase. It appears that exchange interactions result in strong damping of zero sound when the tilting angle between the dipoles and the normal to the plane of confinement is below some critical value. In particular, zero sound cannot propagate if the dipoles are perpendicular to the plane of confinement. At intermediate coupling we find unstable modes that can lead either to collapse of the system or the formation of a density wave. The BCS transition to a superfluid phase, on the other hand, occurs at arbitrarily weak strengths of the dipole-dipole interaction, provided the tilting angle exceeds a critical value. We determine the critical temperature of the transition taking into account many-body effects as well as virtual transitions to higher excited states in the confining potential, and discuss prospects of experimental observations.

References in corpus (17)

• A High Phase-Space-Density Gas of Polar Molecules
• Strongly correlated 2D quantum phases with cold polar molecules: controlling the shape of the interaction potential
• Reactions of ultracold alkali metal dimers
• Stable Topological Superfluid Phase of Ultracold Polar Fermionic Molecules
• Stability of quasi-two-dimensional Bose-Einstein condensates with dominant dipole-dipole interactions
• Quantum fluids of self-assembled chains of polar molecules
• Quantum phases of a Two-Dimensional Dipolar Fermi Gas
• Interlayer superfluidity in bilayer systems of fermionic polar molecules
• Phase space deformation of a trapped dipolar Fermi gas
• Universal rates for reactive ultracold polar molecules in reduced dimensions
• Superfluidity and dimerization in a multilayered system of fermionic polar molecules
• Spontaneous inhomogeneous phases in ultracold dipolar Fermi gases
• Dynamics of ultracold molecules in confined geometry and electric field
• Electric field suppression of ultracold confined chemical rates
• Density instabilities in a two-dimensional dipolar Fermi gas
• Density ordering instabilities of quasi-two-dimensional fermionic polar molecules in single-layer and multi-layer configurations: exact treatment of exchange interactions
• Collective modes of monolayer, bilayer, and multilayer fermionic dipolar liquid

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