Dynamics of shock waves in a superfluid unitary Fermi gas
arXiv:1411.0188 · doi:10.1088/0953-4075/48/17/175301
Abstract
We study the formation and dynamics of shock waves initiated by a repulsive potential in a superfluid unitary Fermi gas by using the order-parameter equation. In the theoretical framework, the regularization process of shock waves mediated by the quantum pressure term is purely dispersive. Our results show good agreement with the experiment of Joseph {\it et al}. [Phys. Rev. Lett. {\bf 106}, 150401 (2011)]. We reveal that the boxlike-shaped density peak observed in the experiment consists of many vortex rings due to the transverse instability of the dispersive shock wave. In addition, we study the transition from a sound wave to subsonic shock waves by increasing the strength of the repulsive potential and show a strong qualitative change in the propagation speed of the wavefronts. In the relatively small strength regime, the speed decreases below the sound speed with increasing the strength as a scaling behavior, while in the large regime the speed remains almost unchanged, which is found to be the same expansion speed of the proliferation of the vortex rings.
19 pages, 5 figures
References in corpus (21)
- Vortices and Superfluidity in a Strongly Interacting Fermi Gas
- Collective excitations of a degenerate gas at the BEC-BCS crossover
- The Equation of State of a Low-Temperature Fermi Gas with Tunable Interactions
- On Dispersive and Classical Shock Waves in Bose-Einstein Condensates and Gas Dynamics
- Precision Measurements of Collective Oscillations in the BEC-BCS Crossover
- Formation of Quantum Shock Waves by Merging and Splitting Bose-Einstein Condensates
- Superfluid Bose-Fermi mixture from weak-coupling to unitarity
- Nonlinear Schrödinger equation for a superfluid Fermi gas from BCS to Bose crossover
- Shear viscosity of a universal Fermi gas near the superfluid phase transition
- Dynamics of a strongly interacting Fermi gas: the radial quadrupole mode
- Collective Modes in a Unitary Fermi Gas across the Superfluid Phase Transition
- Macroscopic Periodic Tunneling of Fermi Atoms in the BCS-BEC Crossover
- Sound propagation in elongated superfluid fermion clouds
- Chladni solitons and the onset of the snaking instability for dark solitons in confined superfluids
- Effective Nonlinear Schrödinger Equations for Cigar-Shaped and Disk-Shaped Fermi Superfluids at Unitarity
- Shear Viscosity of a Unitary Fermi Gas
- Life Cycle of Superfluid Vortices and Quantum Turbulence in the Unitary Fermi Gas
- Shock waves in strongly interacting Fermi gas from time-dependent density functional calculations
- Gradient corrections to the local density approximation for trapped superfluid Fermi gases
- Dynamical properties of the unitary Fermi gas: collective modes and shock waves
- Dispersive effects in the unitary Fermi gas