Imaging quantized vortex rings in superfluid helium to evaluate quantum dissipation

Abstract

The motion of quantized vortices is responsible for many intriguing phenomena in diverse quantum-fluid systems. Having a theoretical model to reliably predict the vortex motion therefore promises a broad significance. But a grand challenge in developing such a model is to evaluate the dissipative force caused by thermal quasiparticles in the quantum fluids scattering off the vortex cores. Various models have been proposed, but it remains unclear which model describes reality due to the lack of comparative experimental data. Here we report a visualization study of quantized vortex rings propagating in superfluid helium. By examining how the vortex rings spontaneously decay, we provide decisive data to identify the model that best reproduces observations. This study helps to eliminate ambiguities about the dissipative force acting on vortices, which could have implications for research in various quantum-fluid systems that also involve similar forces, such as superfluid neutron stars and gravity-mapped holographic superfluids.

Physics news on the Internet: July 2023

“…However, direct experimental observations of the predicted effect have been absent up to now, and theoretical calculations of different groups have given different prognoses concerning the exact mechanism and the magnitude of dissipation. Y Tang (National High Magnetic Field Laboratory and Florida State University, USA) and her co-authors have performed a new experiment, where the dissipation effect in vortices was observed for the first time [4]. To this end, solid deuterium particles were added to liquid helium-4 as markers.…”