Bose Einstein condensation and ferromagnetism of low density Bose gas of particles with arbitrary spin

TL;DR

This paper investigates the ground state properties and excitations of a low-density ultracold spinor Bose gas with arbitrary spin, deriving equations that describe its ferromagnetic and condensate behavior.

Contribution

It derives Gross-Pitaevskii equations for spinor Bose gases with arbitrary spin and analyzes how virtual large momentum contributions influence the ground state and chemical potential.

Findings

Ground state exhibits ferromagnetic structure.

Interaction effects determine spin configuration and chemical potential.

Derived equations describe phase, density, and spin dynamics.

Abstract

Properties of the ground state and the spectrum of elementary excitations are investigated for the low density ultracold spinor 3D Bose gas of particles with arbitrary nonzero spin. Gross-Pitaevskii equations are derived. Within the framework of the considering interaction Hamiltonian it is shown that the ground state spin structure and spin part of the chemical potential is determined by the renormalized interaction, being defined by the contribution of the virtual large momenta. The ferromagnetic structure of the ground state, and the equation of the phase, density, and spin dynamics are obtained from Gross-Pitaevskii equations.