Small amplitude collective modes of a finite-size unitary Fermi gas in deformed traps

Abstract

We have investigated collective breathing modes of a unitary Fermi gas in deformed harmonic traps. The ground state is studied by the Superfluid Local Density Approximation (SLDA) and small-amplitude collective modes are studied by the iterative Quasiparticle Random Phase Approximation (QRPA). The results illustrate the evolutions of collective modes of a small system in traps from spherical to elongated or pancake deformations. For small spherical systems, the influences of different SLDA parameters are significant, and, in particular, a large pairing strength can shift up the oscillation frequency of collective mode. The transition currents from QRPA show that the compressional flow patterns are nontrivial and dependent on the deformation. Finally, the finite size effects are demonstrated to be reasonable when progressing towards larger systems. Our studies indicate that experiments on small and medium systems are valuable for understanding effective interactions in systems with varying sizes and trap deformations.

10 pages, 10 figures

References in corpus (22)

• Many-Body Physics with Ultracold Gases
• Theory of ultracold Fermi gases
• Collective excitations of a degenerate gas at the BEC-BCS crossover
• The Equation of State of a Low-Temperature Fermi Gas with Tunable Interactions
• Precision Measurements of Collective Oscillations in the BEC-BCS Crossover
• Determination of the Superfluid Gap in Atomic Fermi Gases by Quasiparticle Spectroscopy
• Local Density Functional Theory for Superfluid Fermionic Systems: The Unitary Gas
• A Unitary Fermi Supersolid: The Larkin-Ovchinnikov Phase
• Finite amplitude method for the quasi-particle-random-phase approximation
• Goldstone mode and pair-breaking excitations in atomic Fermi superfluids
• Resonantly Interacting Fermions In a Box
• Broyden's Method in Nuclear Structure Calculations
• Finite-Temperature Collective Dynamics of a Fermi Gas in the BEC-BCS Crossover
• Deformed Coordinate-Space Hartree-Fock-Bogoliubov Approach to Weakly Bound Nuclei and Large Deformations
• Effective-Range Dependence of Resonantly Interacting Fermions
• Collective Modes in a Unitary Fermi Gas across the Superfluid Phase Transition
• Large Amplitude Dynamics of the Pairing Correlations in a Unitary Fermi Gas
• Density-functional theory for fermions in the unitary regime
• The role of superfluidity in nuclear incompressibilities
• Sign-free stochastic mean-field approach to strongly correlated phases of ultracold fermions
• Temperature and finite-size effects in collective modes of superfluid Fermi gases
• Dynamic structure factor of a strongly correlated Fermi superfluid within a density functional theory approach