Suthar, K.K.SutharRoy, ArkoArkoRoyAngom, D.D.Angom2025-08-302025-08-302015-04-1310.1103/PhysRevA.91.0436152-s2.0-84929497588https://d8.irins.org/handle/IITG2025/21475We show the emergence of a third Goldstone mode in binary condensates at phase separation in quasi-one-dimensional (quasi-1D) optical lattices. We develop the coupled discrete nonlinear Schrödinger equations using Hartree-Fock-Bogoliubov theory with the Popov approximation in the Bose-Hubbard model to investigate the mode evolution at zero temperature, in particular, as the system is driven from the miscible to the immiscible phase. We demonstrate that the position exchange of the species in the ⁸⁷Rb-⁸⁵Rb system is accompanied by a discontinuity in the excitation spectrum. Our results show that, in quasi-1D optical lattices, the presence of the fluctuations dramatically changes the geometry of the ground-state density profile of two-component Bose-Einstein condensates.falseArticlehttps://arxiv.org/pdf/1412.04051094162213 April 201520043615arJournal21