Vortex Retention Mediated Turbulent Transitions in Self-Gravitating Bosonic and Axionic Condensates

TL;DR

This study compares vortex dynamics and turbulence transitions in self-gravitating bosonic and axionic condensates, revealing how nonlinearities influence vortex retention and energy cascades during spin-down.

Contribution

It provides the first detailed comparison of vortex behavior and turbulence scaling in bosonic versus axionic self-gravitating condensates under rotation slowdown.

Findings

Axionic condensates have more uniform density and smaller size, enabling earlier vortex entry.

Both systems show a Kolmogorov cascade followed by Vinen turbulence during spin-down.

Increased interaction strength causes axionic systems to deviate from Kolmogorov scaling due to vortex retention.

Abstract

We investigate turbulent spin-down dynamics in self-gravitating Bose-Einstein condensates, comparing purely bosonic and axionic (higher-order interacting) systems. Through simulations of the Gross-Pitaevskii-Poisson system, we study condensates pinned to a crust potential undergoing rapid rotation slowdown. We find that axionic condensates exhibit more uniform density profiles and smaller sizes compared to their bosonic counterparts for similar interaction strengths, which facilitates earlier vortex entry. The sudden spin-down triggers vortex depinning and a turbulent cascade. For comparable sizes, both systems exhibit a short-lived Kolmogorov energy cascade ($k^{-5/3}$ scaling) followed by a transition to Vinen turbulence ($k^{-1}$ scaling). Crucially, their responses diverge with increasing interaction strength (and thus condensate size): the axionic system increasingly deviates from Kolmogorov scaling because of enhanced vortex retention, a trend quantitatively confirmed by analyzing the vortex fraction and its dependence on the final rotation frequency. Spectral analysis reveals that the growth of incompressible energy is primarily driven by quantum pressure during vortex detachment, rather than by compressible flows. The compressible spectrum shows thermalization ($k$ scaling). Our results demonstrate how distinct nonlinearities govern vortex dynamics and turbulent dissipation in self-gravitating quantum fluids.