Eur. Phys. J. D (2013) 67: 140
https://doi.org/10.1140/epjd/e2013-30418-x

Regular Article

Soliton appearing in boson-fermion mixture at the third order of the interaction radius

¹ Department of Theoretical Physics, Physics Faculty, Moscow State University, Moscow, Russian Federation
² Department of General Physics, Physics Faculty, Moscow State University, Moscow, Russian Federation

^a e-mail: andreevpa@physics.msu.ru

Received: 5 July 2012
Received in final form: 19 November 2012
Published online: 16 July 2013

Abstract

In this paper we consider an ultra-cold mixture of boson and fermion atoms on the basis of quantum hydrodynamics. Small one-dimensional perturbations in such systems are being analyzed. A possibility is shown for soliton solutions of a new type to appear if the third order of the interaction radius is taken into account in the analysis of interactions. A fermion-fermion interaction occurs in explicit form if this approximation is accepted. The conditions that lead to occurrence of this type of soliton in a mixture of boson and fermion atoms were investigated. Restrictions on the fermion-fermion interaction were found that are necessary for this kind of perturbations to appear in the system. Conditions determining whether perturbances would be a condensed soliton or a rarefied soliton are shown.