Dynamical Structure Factor and Spin-Density Separation for a Weakly-Interacting Two-Component Bose Gas

TL;DR

This paper demonstrates that spin-density separation occurs in higher-dimensional weakly-interacting two-component Bose gases, influenced by interaction ratios, with distinct dynamical structure factor signatures for different regimes.

Contribution

It extends the understanding of spin-density separation beyond 1D to higher dimensions and analyzes the effects of interaction ratios on excitations and dynamical structure factors.

Findings

Spin-density separation occurs in higher dimensions.

The nature of spin waves depends on the interaction ratio α.

Dynamical structure factor shows distinct peaks for different regimes.

Abstract

We show that spin-density separation in a Bose gas is not restricted to 1D but also occurs in higher dimension. The ratio ($\alpha$) of the intra-species atom-atom interaction strength to the inter-species interaction strength, strongly influences the dynamics of spin-density separation and the elementary excitations. The density wave is phonon-like for all values of $\alpha$. For $\alpha<1$, spin wave is also phonon-like. The spin waves have a quadratic dispersion in the $\alpha=1$ coupling regime, while in the phase separated regime ($\alpha>1$) the spin waves are found to be damped. The dynamical structure factor (DSF) reveals two distinct peaks corresponding to the density and spin waves for $\alpha \le 1$. For $\alpha > 1$ there is only one DSF peak corresponding to the density wave.