Strongly Spinor Ferromagnetic Bose Gases

TL;DR

This paper investigates the phase diagrams of ferromagnetic spin-1 Bose gases, revealing two superfluid phases with first-order transitions due to the interplay of ferromagnetism and quadratic Zeeman energy, especially in lattice systems like ${}^7$Li.

Contribution

It provides a detailed analysis of the phase structure of ferromagnetic spinor Bose gases in lattice systems, highlighting the existence of first-order phase transitions induced by external magnetic fields.

Findings

Identification of two distinct superfluid phases.

Discovery of first-order phase transitions between these phases.

Contrast with continuum system behavior.

Abstract

By studying the zero-temperature and nonzero-temperature phase diagrams of the ferromagnetic spin-1 Bose-Hubbard model under an external magnetic field, we find that the competition between ferromagnetism and the quadratic Zeeman energy yields two superfluid phases, which feature discontinuous first-order phase transitions between them for a strongly spinor Bose gas such as ${}^7$Li, contrary to the corresponding continuum system.