Broken-axisymmetry state and magnetic state diagram of spin-1 condensate through the prism of quadrupole degrees of freedom

Abstract We theoretically study a weakly interacting gas of spin-1 atoms with Bose–Einstein condensate in external magnetic field within the Bogoliubov approach. To this end, contrast to previous studies, we employ general Hamiltonian, which includes both spin and quadrupole exchange interactions as well couplings moment (the linear quadratic Zeeman terms). The latter is responsible for emergence broken-axisymmetry state. also reexamine ferromagnetic, quadrupolar, paramagnetic states employing proposed Hamiltonian. For all states, find relevant thermodynamic characteristics such magnetization, moment, potential. obtain three-branch excitation spectrum show that state can be prepared at three different regimes applied field. Finally, present diagrams each regime realizing