Novel Fermi Liquid of 2D Polar Molecules

Abstract

We study Fermi liquid properties of a weakly interacting 2D gas of single-component fermionic polar molecules with dipole moments $d$ oriented perpendicularly to the plane of their translational motion. This geometry allows the minimization of inelastic losses due to chemical reactions for reactive molecules and, at the same time, provides a possibility of a clear description of many-body (beyond mean field) effects. The long-range character of the dipole-dipole repulsive interaction between the molecules, which scales as $1/r^3$ at large distances $r$, makes the problem drastically different from the well-known problem of the two-species Fermi gas with repulsive contact interspecies interaction. We solve the low-energy scattering problem and develop a many-body perturbation theory beyond the mean field. The theory relies on the presence of a small parameter $k_F{r}_{\ast }$, where $k_F$ is the Fermi momentum, and $r_{\ast }=m{d}^2/{\hslash }^2$ is the dipole-dipole length, with $m$ being the molecule mass. We obtain thermodynamic quantities as a series of expansion up to the second order in $k_F{r}_{\ast }$ and argue that many-body corrections to the ground-state energy can be identified in experiments with ultracold molecules, like it has been recently done for ultracold fermionic atoms. Moreover, we show that only many-body effects provide the existence of zero sound and calculate the sound velocity.

19 pages, 2 figures

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• Dipolar physics: A review of experiments with magnetic quantum gases
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• Ground-state and dynamical properties of two-dimensional dipolar Fermi liquids
• Itinerant ferromagnetism in 1D two-component Fermi gases
• Fixed-node diffusion Monte Carlo study of the BCS-BEC crossover in a bilayer system of fermionic dipoles
• Unconventional superfluids of fermionic polar molecules in a bilayer system
• Zero sound in a two-dimensional dipolar Fermi gas
• Two-dimensional Mixture of Dipolar Fermions: Equation of State and Magnetic Phases
• Fulde-Ferrell-Larkin-Ovchinnikov state in bilayer dipolar systems
• Second-order interaction corrections to the Fermi surface and the quasiparticle properties of dipolar fermions in three dimensions
• Bound Chains of Tilted Dipoles in Layered Systems
• Competing many-body instabilities in two-dimensional dipolar Fermi gases
• Self-consistent field theory of polarized BEC: dispersion of collective excitation
• Pseudopotentials for an ultracold dipolar gas
• Quantum gas of polar molecules ensembles at ultralow temperatures: f-wave superfluids
• Wigner Crystallization in Two Dimensions: Evolution from Long- to Short-Ranged Forces
• Composite quasiparticles in strongly-correlated dipolar Fermi liquids
• Dipolar fermions in a multilayer geometry
• Superfluid transition in disordered dipolar Fermi gases
• Quantum Degenerate Majorana Surface Zero Modes in Two-Dimensional Space
• Field-induced ferromagnetic phase transition in 2D Fermi systems with magnetic dipole-dipole interaction