2026/03/05 by Yiming Xing, Yousef Alihosseini, Sosuke Inui +1 · 1 voice
Physics and Astronomy · #cond-mat.other #physics.flu-dyn
Quantized vortex dynamics in superfluid 4He (He~II) are widely regarded as well established: circulation is quantized in units of κ=h/m4, vortices carrying more than one quantum are expected to split into singly quantized filaments, and vortex rings shrink while accelerating due to dissipation from thermal-quasiparticle scattering. Using particle tracking velocimetry with frozen deuterium tracers, we uncover rare vortex-bound particle events that disrupt this canonical picture. In a class of events exhibiting the acceleration characteristic of shrinkage driven vortex ring motion, the measured kinematics cannot be reconciled with a singly quantized ring. Instead, they require an effective circulation nκ with n>1, directly challenging the standard expectation that multiquantum vortices are short lived. A more prosaic possibility is that the inferred nκ arises from a bundle of closely spaced singly quantized rings, which could generate similar large-scale motion. However, this scenario is disfavored by vortex-filament simulations that show rapid bundle dispersion. Furthermore, the persistence of particle trapping at the observed high speeds suggests a much deeper core trapping potential, consistent only with a truly multiquantum core. Together, these results point to anomalously long-lived multiquantum rings, a striking puzzle that calls for dedicated scrutiny beyond the prevailing paradigm.