Free expansion of fermionic dark solitons in a boson-fermion mixture

TL;DR

This paper models and simulates the free expansion of fermionic dark solitons in a boson-fermion mixture, highlighting their formation, evolution, and potential for experimental detection.

Contribution

It introduces a dynamical mean-field-hydrodynamic model for fermionic dark solitons in a mixed quantum gas, extending previous pure boson studies.

Findings

Dark solitons exhibit a growing central notch during free expansion.

Numerical simulations confirm the soliton's stability and evolution.

Potential for experimental observation of fermionic dark solitons after expansion.

Abstract

We use a time-dependent dynamical mean-field-hydrodynamic model to study the formation of fermionic dark solitons in a trapped degenerate fermi gas mixed with a Bose-Einstein condensate in a harmonic as well as a periodic optical-lattice potential. The dark soliton with a "notch" in the probability density with a zero at the minimum is simulated numerically as a nonlinear continuation of the first vibrational excitation of the linear mean-field-hydrodynamic equations, as suggested recently for pure bosons. We study the free expansion of these dark solitons as well as the consequent increase in the size of their central notch and discuss the possibility of experimental observation of the notch after free expansion.