Patterns, spin-spin correlations and competing instabilities in driven quasi-two-dimensional spin-1 Bose-Einstein condensates

Abstract: We analyze the formation of transient patterns and spin-spin correlations in quasi-two-dimensional spin-1 homogeneous Bose-Einstein condensates subjected to parametric driving of $s$-wave scattering lengths. The dynamics for an initial ferromagnetic phase is identical to that of a scalar condensate. In contrast, intriguing dynamics emerges for an initial polar state. For instance, we show that competition exists between density patterns and spin-mixing dynamics. Dominant spin-mixing dynamics lead to a gas of polar core vortices and anti-vortices of different spin textures. The density modes of the Bogoliubov spectrum govern the wavenumber selection of Faraday patterns. The spin modes determine the vortex density and the spatial dependence of spin-spin correlation functions. When the density patterns outgrow the spin-mixing dynamics, the spin-spin correlations decay exponentially with a correlation length of the order a spin healing length; otherwise, they exhibit a Bessel function dependence. Strikingly, competing instabilities within density and spin modes emerge when both scattering lengths are modulated at different frequencies and appropriate modulation amplitudes. The competing instability leads to a superposition of density patterns or correlation functions of two distinct wavelengths. Our studies reveal that fine control over the driven dynamics can be attained by tuning interaction strengths, quadratic Zeeman field, driving frequencies, and amplitudes.