Polarized Rabi-coupled and spinor boson droplets

Abstract

Self-bound quantum droplets form when the mean-field tendency of the gas to collapse is stabilized by the effectively repulsive beyond mean-field fluctuations. The beyond mean-field effects depend on Rabi-frequency $\omega_R$ and quadratic Zeeman effect $q$ for the Rabi-coupled Bose mixtures and the spinor gases, respectively. The effects of varying $\omega_R$ and $q$ on the quantum droplet have recently been examined for unpolarized Rabi-coupled Bose mixture with zero detuning $\delta = 0$ and unpolarized spinor gas with $\langle F_z \rangle=0$. In this paper, we theoretically explore the stability of the droplet phase for polarized $\delta \neq 0$ Rabi-coupled Bose mixture and $\langle F_z \rangle \neq 0$ spinor gas. We calculate the Lee-Huang-Yang corrections for both gases with polarized order parameters and obtain the phase diagram of the droplets on the parameter space of $\omega_R$-$\delta$ and $q$-$p$ for Rabi-coupled mixture and spinor gas, respectively. Finally, we highlight the similarities and differences between the two systems and discuss their experimental feasibility.