Dynamics of a strongly interacting Fermi gas: the radial quadrupole mode

Abstract

We report on measurements of an elementary surface mode in an ultracold, strongly interacting Fermi gas of 6Li atoms. The radial quadrupole mode allows us to probe hydrodynamic behavior in the BEC-BCS crossover without being influenced by changes in the equation of state. We examine frequency and damping of this mode, along with its expansion dynamics. In the unitarity limit and on the BEC side of the resonance, the observed frequencies agree with standard hydrodynamic theory. However, on the BCS side of the crossover, a striking down shift of the oscillation frequency is observed in the hydrodynamic regime as a precursor to an abrupt transition to collisionless behavior; this indicates coupling of the oscillation to fermionic pairs.

11 pages, 11 figures v2: minor changes

References in corpus (7)

• Observation of Bose-Einstein Condensation of Molecules
• Observation of the Pairing Gap in a Strongly Interacting Fermi Gas
• Crossover from a molecular Bose-Einstein condensate to a degenerate Fermi gas
• Collective excitations of a degenerate gas at the BEC-BCS crossover
• Pure Gas of Optically Trapped Molecules Created from Fermionic Atoms
• Precision Measurements of Collective Oscillations in the BEC-BCS Crossover
• Coupling of hydrodynamics and quasiparticle motion in collective modes of superfluid trapped Fermi gases

Cited by in corpus (18)

• Theory of ultracold Fermi gases
• Efficient all-optical production of large ${}^6$Li quantum gases using D${}_1$ gray-molasses cooling
• Collective oscillations of a Fermi gas in the unitarity limit: Temperature effects and the role of pair correlations
• Finite-Temperature Collective Dynamics of a Fermi Gas in the BEC-BCS Crossover
• Collisions between tunable halo dimers: exploring an elementary four-body process with identical bosons
• Signature of the FFLO phase in the collective modes of a trapped ultracold Fermi gas
• Breathing Mode of a BEC Repulsively Interacting with a Fermionic Reservoir
• Observation of interference between two molecular Bose-Einstein condensates
• Collective modes of trapped Fermi gases with in-medium interaction
• Finite temperature damping of collective modes of a BCS-BEC crossover superfluid
• Numerical solution of the Boltzmann equation for trapped Fermi gases with in-medium effects
• Pure Goldstone mode in the quench dynamics of a confined ultracold Fermi gas in the BCS-BEC crossover regime
• Trap anharmonicity and sloshing mode of a Fermi gas
• Radial quadrupole and scissors modes in trapped Fermi gases across the BCS phase transition
• Lifetime of angular momentum in a rotating strongly interacting Fermi gas
• Higher-Harmonic Collective Modes in a Trapped Gas from Second-Order Hydrodynamics
• Dipole-Mode Spectrum and Hydrodynamic Crossover in a Resonantly Interacting Two-Species Fermion Mixture
• Coupled oscillator model of a trapped Fermi gas at the BEC-BCS crossover