Self-localization of a small number of Bose particles in a superfluid Fermi system

TL;DR

This paper investigates how a few Bose particles can self-localize within a superfluid Fermi system, forming bound states or solitons, with analysis of effects at different dimensions and temperatures.

Contribution

It demonstrates the self-localization phenomena of Bose particles in superfluid fermionic systems across 1D and 3D, including effects of interactions and temperature.

Findings

Self-localization occurs for repulsive interactions in 3D.

Bose particles form vector solitons in 1D with fermions.

Thermal effects minimally impact self-localization.

Abstract

We consider self-localization of a small number of Bose particles immersed in a large homogeneous superfluid mixture of fermions in three and one dimensional spaces. Bosons distort the density of surrounding fermions and create a potential well where they can form a bound state analogous to a small polaron state. In the three dimensional volume we observe the self-localization for repulsive interactions between bosons and fermions. In the one dimensional case bosons self-localize as well as for attractive interactions forming, together with a pair of fermions at the bottom of the Fermi sea, a vector soliton. We analyze also thermal effects and show that small non-zero temperature affects the pairing function of the Fermi-subsystem and has little influence on the self-localization phenomena.