Low Temperature Physics: 47, 700 (2021); https://doi.org/10.1063/10.0005559
Fizika Nizkikh Temperatur: Volume 47, Number 8 (August 2021), p. 760-773    ( to contents , go back )

Multipole degrees of freedom in physics of high-spin quantum atomic gases

M.S. Bulakhov1,2, A. S. Peletminskii1,2, and Yu. V. Slyusarenko1,2

1Akhiezer Institute for Theoretical Physics, National Science Center “Kharkiv Institute of Physics and Technology” Kharkiv 61108, Ukraine

2V. N. Karazin Kharkiv National University, Kharkiv 61022, Ukraine
E-mail: aspelet@kipt.kharkov.ua
pos Анотація:1045

Received April 2, 2021, published online June 25, 2021

Abstract

We provide the general arguments that quantum atomic gases of interacting high-spin atoms represent a physical system in which the multipole (hidden) degrees of freedom may be manifested. Their manifestation occurs when the interatomic interaction is of non-local type. For a local interaction described by the s-wave scattering length, the multipole degrees of freedom do not reveal themselves. To illustrate our findings, we theoretically examine the phenomenon of Bose–Einstein condensation in an interacting gas of spin-1 atoms in an external magnetic field. This study is based on the SU(2) invariant Hamiltonian, which has a bilinear structure in the spin and quadrupole operators along with the scalar term. It is shown that depending on the conditions imposed on the interaction amplitudes (stability conditions), the ground state of the system may exhibit three different phases: quadrupolar, ferromagnetic, and paramagnetic. The basic thermodynamic characteristics affected by hidden degrees of freedom are found for all phases.

Key words: high-spin atoms, quantum atomic gases, Bose–Einstein condensation.

Download 484510 byte View Contents