Scientists from Osaka University’s Graduate School of Engineering Science have demonstrated how vortices that form inside superfluid helium can capture silicon nanoparticles.
The strong interaction between light and silicon nanoparticles in this work opens up new avenues for optical research into other quantum features of superfluid helium, such as the optical manipulation of quantized vortices.
We may find the principles of quantum mechanics to be rather alien, with particles that occasionally behave like waves and vice versa. We typically anticipate that strange quantum activity will only occur at very small scales.
However, the consequences of the waviness can be seen even at macroscopic sizes when some materials, like helium-4, are cooled to extremely low temperatures.
This “supercooled” helium is an illustration of a Bose-Einstein condensation, where waves that describe the atoms overlap until the entire fluid resembles a single particle.
Due to the fact that the transition to a superfluid in helium-4 takes place at temperatures that are somewhat manageable, this process has no analog in conventional physics and serves as a good environment for testing ideas of quantum mechanics. However, it is still necessary to be able to see how the superfluid is moving.
We were able to provide direct experimental evidence that dense silicon nanoparticles are attracted to quantized vortices, and stabilize along the vortex core.
Yosuke Minowa
Now, a group of scientists led by Osaka University have utilized silicon nanoparticles to assist highlight the characteristics of superfluid helium, much like how throwing pebbles can let you see how water flows down a waterfall.
“We were able to provide direct experimental evidence that dense silicon nanoparticles are attracted to quantized vortices, and stabilize along the vortex core,” first author Yosuke Minowa says.
Any rotational motion in superfluid helium can only take the form of quantized vortices, which is one of its unique characteristics. Each of these little, distinct whirlpools has a defined quantity of angular momentum.
The phenomenon of vortex reconnection, in which lines of vortices coalesce and exchange their components, was studied by scientists using the nanoparticle technique. The vortex lines were easily seen due to the light scattering from the nanoparticles.
“Our proposed technique enables us to use many different materials as tracer particles of quantized vortices,” Minowa explains.
Scientists may be able to comprehend more esoteric quantum systems, like the critical current in high-temperature superconductors, better by studying quantized vortices in superfluid helium.
