In a groundbreaking study, scientists showed us what it's like to touch a quantum superfluid. They did this by putting a special probe into supercold helium, just a tiny bit warmer than absolute zero. This study, led by physicist Samuli Autti from Lancaster University in the UK, marks the first time we've come close to understanding the sensation of interacting with the quantum Universe without enduring extreme cold or ruining experiments.
What Are Superfluids?
Superfluids are an extraordinary state of matter characterized by their absence of viscosity or friction, behaving like a perfectly flowing fluid. You can make them using two types of helium: helium-4 and helium-3.
When helium-4 is extremely cold, its tiny particles, known as bosons, gather closely and behave as one super-atom. Helium-3, on the other hand, is composed of fermions, a different class of particles with unique spinning properties. When cooled below a critical temperature, helium-3 fermions form what scientists call Cooper pairs. These Cooper pairs function as composite bosons, behaving like a superfluid.
The Unique Experiment
Autti and his team focused their experiments on helium-3 fermionic superfluids. They discovered that, despite their fragility, Cooper pairs could accommodate a wire without breaking or disrupting the superfluid's flow. This led to the development of a probe to closely investigate the superfluid's properties.
The results of the experiment are intriguing. The superfluid's surface forms an independent two-dimensional layer that efficiently dissipates heat away from the probe. However, the bulk of the superfluid underneath behaves as if it were a vacuum, remaining passive and devoid of any discernible sensation.
The probe only interacted with the two-dimensional surface layer, while the bulk of the superfluid remained isolated unless subjected to a substantial energy input. This flat layer describes the heat and movement characteristics of the superfluid.
What It Feels Like
If you could insert your finger into this superfluid, it would feel rather peculiar. The majority of the superfluid gives the impression of emptiness, while a two-dimensional subsystem along the edges, resembling your finger, is responsible for heat transfer. In essence, the superfluid would seem two-dimensional to your touch, redefining our understanding of superfluid helium-3.
Implications of the Discovery
The significance of this discovery is profound. Helium-3 superfluid is one of the purest materials known, making it highly valuable for studying collective matter states like superfluids. Understanding the behavior of its two-dimensional layer holds the potential to shed light on quasiparticle behavior, topological defects, and quantum energy states. This, in turn, can revolutionize our comprehension of this versatile macroscopic quantum system.
In summary, this experiment offers a glimpse into the fascinating realm of quantum superfluids. It deepens our understanding of their characteristics and their potential applications in quantum physics.
Exciting new findings about quantum superfluids will soon appear in Nature Communications and can also be found on arXiv. This study adds to our growing knowledge of the mysterious quantum superfluid world.