Eur. Phys. J. D (2015) 69: 124
https://doi.org/10.1140/epjd/e2015-50686-6

Regular Article

A binary mixture of spin-1 atoms in a weak magnetic field: the effect of quadratic Zeeman energy

¹ College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, P.R. China
² Beijing Computational Science Research Center, Beijing 100084, P.R. China

^a e-mail: yfpan@nuaa.edu.cn

Received: 16 September 2014
Received in final form: 11 January 2015
Published online: 8 May 2015

Abstract

The effect of quadratic Zeeman energy (q) is studied for a binary mixture of spin-1 Bose-Einstein condensates with antiferromagnetic spin interactions in a weak magnetic field. Despite the low strength of the magnetic field, the ground states contain some new phases due to the competition of q, p (linear Zeeman energy) and spin interactions. The phase diagram in the (q,p) plane is constructed and the stability for different phases is discussed in a low-energy limit. The elementary excitations of a special phase is calculated by Bogoliubov theory, showing the different effects of q and p.