Thermal effects on the spin-domain phases of high spin- f Bose-Einstein condensates with rotational symmetries

Abstract

In spinor Bose Einstein condensates (BEC) gases, a fraction of its thermally excited atoms can still interact with the condensate ground state, leading to spin-spin interactions that can modify the main features of its spin-phase diagrams. In this work we study the spin-phase diagram of a BEC of general spin-$f$ and fully characterize its noncondensate thermal fraction. The latter provided that the condensate ground state lies within a spin phase with rotational symmetry. The study is based in the Hartree-Fock approximation in conjunction with the Majorana stellar representation approach for pure and mixed quantum states and the use of point-group symmetry arguments. The method allows us to study the phase diagram of spinorial BECs with usual point-group symmetries, including those with some exotic phases associated to the platonic solids ($f=2,3,4,$ and 6), which are known to lead to non-Abelian topological excitations. In addition, we explore the temperature effects on the admissible spin-phase domains for general spin values, as well as its physical implications on their multipolar magnetic moments.