Shawan K. Jha | Searcharxiv

arXiv2026

Faraday pattern formation in dipolar superfluid and supersolid quantum gases

We investigate Faraday instabilities in three-dimensional parametrically driven trapped dipolar quantum gases within the framework of the extended Gross-Pitaevskii equation. In the superfluid regime, periodic modulation of the short-range interactions induces the resonant excitation of discrete polygonal surface modes displaying sub-harmonic response. The resonance frequencies and the parametric windows of instability are accurately captured by an appropriate Mathieu equation, further corroborating our simulations. It is also shown that dipolar interactions in superfluids shift the resonance frequencies to lower values compared to their non-dipolar counterparts. Near the superfluid-to-supersolid transition, intrinsic density undulations associated with the softened roton mode accelerate pattern formation, yielding hybrid surface and bulk excitations. The bulk patterns prevail deeper in the supersolid regime, emerging from droplet collisions with the superfluid background. Our results reveal a crossover from surface collective modes to hybrid surface-bulk excitations and demonstrate how parametric driving dictates pattern formation in long-range interacting quantum fluids.

cond-mat.quant-gas↗

arXiv2025

Vortex configuration dependent equilibrium and non-equilibrium states in two-dimensional quantum turbulence

In this work, we analyze the evolution of four vortex configurations, namely, dipole, plasma, cluster, and lattice, using the two-dimensional mean-field Gross-Pitaevskii equation, focusing on their dynamical decay and approach to the equilibrium. Our analysis reveals that the cluster vortex configuration reaches equilibrium more rapidly than the others, while the dipole, plasma, and lattice configurations exhibit persistent non-equilibrium behavior, tending toward non-thermal fixed points. Specifically, the cluster configuration follows Kolmogorov-like scaling ($\varepsilon^{i}(k)\sim k^{-5/3}$) in the incompressible spectrum, while the other configurations follow Vinen-like scaling ($\varepsilon^{i}(k)\sim k^{-1}$). In the compressible spectrum, the cluster case exhibits a $k$ scaling, indicating full mode equilibration, while for the other configurations, the modes thermalize only above a critical wave number. Additionally, the transfer function for the cluster configuration displays a Gaussian distribution, typical of equilibrium states, while the other configurations exhibit skewed Gaussian or exponential distributions, indicative of their non-equilibrium nature. Finally, the particle number spectra show that the cluster case follows dynamical scaling closer to equilibrium, while the dipole, plasma, and lattice configurations evolve towards non-thermal fixed points. Our findings provide new insights into the dynamics of vortex configurations and their approach to equilibrium or non-equilibrium states, offering guidance for future studies on quantum turbulence and its control.

cond-mat.quant-gas↗