Static properties and spin dynamics of the ferromagnetic spin-1 Bose gas in magnetic field

TL;DR

This paper investigates the static properties and spin dynamics of ferromagnetic spin-1 Bose gases under magnetic fields, revealing phase transitions and critical behaviors through mean-field and RPA methods.

Contribution

It provides a detailed analysis of phase diagrams and spin dynamics in ferromagnetic spin-1 Bose gases, including the identification of a first-order transition and critical soft modes.

Findings

Existence of a first-order phase transition with coexisting magnetizations

Behavior of soft modes at the magnetic phase transition

Thermodynamic properties derived using mean-field approximation

Abstract

Properties of spin-1 Bose gases with ferromagnetic interaction in the presence of a nonzero magnetic field are studied. The equation of state and thermodynamic quantities are worked out with the help of a mean-field approximation. The phase diagram besides Bose-Einstein condensation contains a first order transition where two values of the magnetization coexist. The dynamics is investigated with the help of the Random Phase Approximation. The soft mode corresponding to the critical point of the magnetic phase transition is found to behave like in conventional theory.