For the first time, scientists have successfully stirred a strange type of matter known as “supersolid” – a state of matter that has a solid structure but can flow like a liquid.
Researchers have recently reported a significant discovery: for the first time, they have successfully stirred a strange type of matter called “supersolid” – a state of matter with a solid structure that can flow like a liquid.
This provides direct evidence that this matter possesses special properties, being both solid and liquid, offering new insights into quantum phenomena.
In everyday life, we are familiar with four basic states of matter: solid, liquid, gas, and plasma. However, physicists have long studied anomalous states of matter that form under extremely harsh conditions – such as at near absolute zero temperatures (around -273.15 degrees Celsius) or at very high energy levels.
Under these conditions, matter begins to exhibit behaviors very different from what we observe in nature.
Liquids like water or gases can have varying viscosities, meaning the degree of resistance to their movement. For example, honey has a higher viscosity than water.
However, superfluid – a form of extremely cold matter – has no viscosity, meaning there is no resistance, allowing it to flow freely without ever slowing down.
If you stir a superfluid in a cup, it will continue to flow indefinitely without stopping.
This is a type of matter that exhibits properties of both solid and superfluid. (Illustration: Sci.news).
More than 50 years ago, physicists predicted the existence of a state of matter called “supersolid.”
This is a type of matter that exhibits properties of both solid and superfluid, where some atoms can move through a rigid crystal structure without encountering any resistance – as if they are flowing while still maintaining solid characteristics.
Previous researchers have observed crystalline structures within supersolid materials using various methods.
However, directly observing how this matter moves remained an unanswered question until a new study led by physicist Francesca Ferlaino at the University of Innsbruck (Austria), published in the journal Nature on November 6.
Ferlaino’s research team successfully stirred a supersolid and observed small vortices, known as “quantum vortices” – characteristic signatures of superfluid properties.
Ferlaino explains: “Imagine you have a cup of coffee and you stir it gently with a spoon. You will see the coffee swirling around the center of the cup, and if you look closely, you will see a small vortex in the middle where the liquid is spinning the fastest. This is an example of a vortex in a normal liquid.”
However, what would happen if you replaced the coffee with a superfluid? Ferlaino notes: “If you stir slowly, you will be surprised to see that the superfluid does not swirl with the spoon – it remains completely still, as if nothing is disturbing it. But if you stir faster, instead of just creating a large vortex in the center, a magical thing happens: numerous small vortices, called quantum vortices, begin to appear.”
These quantum vortices resemble small holes in the liquid, each vortex spinning at a specific speed. Ferlaino explains: “Instead of just clustering in one spot, they arrange themselves into beautiful and regular patterns on the surface of the superfluid, similar to holes in a piece of Gruyère cheese, but completely orderly.”
According to the researchers, this discovery not only enhances our understanding of the supersolid state but also opens up possibilities for simulating phenomena that only occur under extremely harsh conditions, such as at the centers of neutron stars – the extremely dense cores of stars when they explode into supernovae. They believe that changes in the spin rates of neutron stars could be a result of superfluid quantum vortices trapped inside them.
