Dark soliton collisions in superfluid Fermi gases

Autor: W Van Alphen, G Lombardi, S N Klimin, J Tempere
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: New Journal of Physics, Vol 20, Iss 5, p 053052 (2018)
Druh dokumentu: article
ISSN: 1367-2630
DOI: 10.1088/1367-2630/aac2a9
Popis: In this work dark soliton collisions in a one-dimensional superfluid Fermi gas are studied across the BEC-BCS crossover by means of a recently developed finite-temperature effective field theory (2015 Eur. Phys. J. B 88 122). The evolution of two counter-propagating solitons is simulated numerically based on the theory’s nonlinear equation of motion for the pair field. The resulting collisions are observed to introduce a spatial shift into the trajectories of the solitons. The magnitude of this shift is calculated and studied in different conditions of temperature and spin-imbalance. When moving away from the BEC-regime, the collisions are found to become inelastic, emitting the lost energy in the form of small-amplitude density oscillations. This inelasticity is quantified and its behavior analyzed and compared to the results of other works. The dispersion relation of the density oscillations is calculated and is demonstrated to show a good agreement with the spectrum of collective excitations of the superfluid.
Databáze: Directory of Open Access Journals