Finite-frequency normal and superfluid drag effects in two-component atomic Bose-Einstein condensates

Physical Review A: Atomic, Molecular, and Optical physics. 2024. Vol. 110. No. 1. Article 013318.

Azat F. Aminov, Alexey A. Sokolik, Yurii E. Lozovik

Two-component systems consisting of mutually interacting particles can demonstrate both intracomponent transport effects and intercomponent entrainment (or drag) effects. In the presence of superfluidity, the intracomponent transport is characterized by dissipative conductivity and superfluid weight in the framework of two-fluid model, and intercomponent entrainment gives rise to normal and nondissipative drag effects. We present unified treatment of all these effects for spatially homogeneous two-component atomic Bose-Einstein condensates based on the Bogoliubov theory, focusing specifically on the drag effects. Calculating finite-frequency intra- and intercomponent conductivities with taking into account quasiparticle damping, we derive and numerically check analytical Drude-like approximations applicable at low frequencies and Lorentz-like approximations applicable at higher frequencies in the vicinity of the resonant energy of spin-to-density Bogoliubov quasiparticle conversion. As possible physical realizations of two-component atomic systems, we consider three-dimensional Bose-Bose mixtures and closely spaced two-layered systems of magnetic dipolar atoms.

Keywords: superfluidity, сверхтекучесть, Bose condensation, бозе-конденсация, ультрахолодные квантовые газы, ultracold quantum gases, эффект увлечения, drag effects

Publication based on the results of: Modeling of physical processes in continuous and discrete media (2024)