Dipolar Fermi gases in anisotropic traps

Journal Article · Tue Jun 15 04:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.81.063629· OSTI ID:21437951

Lima, Aristeu R. P.; Pelster, Axel ^[1]

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1. Institut fuer Theoretische Physik, Freie Universitaet Berlin, Arnimallee 14, D-14195 Berlin (Germany)

The quest for quantum degenerate Fermi gases interacting through the anisotropic and long-range dipole-dipole interaction is an exciting and fast developing branch within the cold-atom research program. Recent experimental progress in trapping, cooling, and controlling polar molecules with large electric dipole moments has, therefore, motivated much theoretical effort. In a recent letter, we have briefly discussed the application of a variational time-dependent Hartree-Fock approach to study theoretically both the static and the dynamic properties of such a system in a cylinder-symmetric harmonic trap. We focused on the hydrodynamic regime, where collisions ensure the equilibrium locally. Here we present a detailed theory extended to encompass the general case of a harmonic trap geometry without any symmetry. After deriving the equations of motion for the gas, we explore their static solutions to investigate key properties like the aspect ratios in both real and momentum space as well as the stability diagram. We find that, despite the lack of symmetry of the trap, the momentum distribution remains cylinder symmetric. The equations of motion are then used to study the low-lying hydrodynamic excitations, where, apart from the quadrupole and monopole modes, the radial quadrupole mode is also investigated. Furthermore, we study the time-of-flight dynamics as it represents an important diagnostic tool for quantum gases. We find that the real-space aspect ratios are inverted during the expansion, while that in momentum space becomes asymptotically unity. In addition, anisotropic features of the dipole-dipole interaction are discussed in detail. These results could be particularly useful for future investigations of strongly dipolar heteronuclear polar molecules deep in the quantum degenerate regime.

• OSTI ID: 21437951
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 6 Vol. 81; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANISOTROPY
APPROXIMATIONS
ASPECT RATIO
ATOM COLLISIONS
ATOMS
CALCULATION METHODS
COLLISIONS
DIFFERENTIAL EQUATIONS
DIMENSIONLESS NUMBERS
DIPOLE MOMENTS
DIPOLES
ELECTRIC DIPOLE MOMENTS
ELECTRIC MOMENTS
ENERGY-LEVEL TRANSITIONS
EQUATIONS
EQUATIONS OF MOTION
EXCITATION
FERMI GAS
FLUID MECHANICS
HARTREE-FOCK METHOD
HYDRODYNAMICS
MECHANICS
MOLECULES
MULTIPOLES
PARTIAL DIFFERENTIAL EQUATIONS
TIME DEPENDENCE
TIME-OF-FLIGHT METHOD
TRAPS
VARIATIONAL METHODS