Supersolid facts for kids

A supersolid is a very special kind of material. Imagine a solid object, like an ice cube, but instead of staying perfectly still, its particles can flow through each other without any friction! That's what a supersolid is: it's a solid, but it also acts like a superfluid.

In a normal solid, atoms are locked in place, vibrating but not moving around. In a liquid, atoms can move past each other. A superfluid is an even stranger liquid that flows perfectly without any stickiness or resistance (called viscosity). A supersolid combines these two ideas: it has a fixed shape like a solid, but its particles can also move freely through it like a superfluid.

What is a Supersolid?

A supersolid is a unique state of matter that has two main properties at the same time:

• Solid-like structure: Its atoms are arranged in a regular, repeating pattern, just like in a crystal. This gives it a fixed shape.
• Superfluid-like flow: Despite having a solid structure, some of its particles can move through the material without any energy loss. It's like having a tiny, invisible river flowing through a frozen landscape.

This combination of properties makes supersolids very interesting to scientists who study condensed matter physics, which is a branch of science that looks at the physical properties of materials.

How is a Supersolid Different?

To understand a supersolid, let's compare it to other states of matter:

• Solids: Have a fixed shape and volume. Atoms are tightly packed and don't move much.
• Liquids: Have a fixed volume but take the shape of their container. Atoms can move past each other.
• Gases: Have no fixed shape or volume. Atoms move freely and are far apart.
• Superfluids: Are liquids that flow without any friction. They can even climb walls!
• Supersolids: Are solids that also have the frictionless flow of a superfluid.

Imagine a sponge that is also completely soaked with water, and the water can move through the sponge without any resistance. A supersolid is a bit like that, but at the atomic level.

The History of Supersolids

The idea of a supersolid was first suggested by scientists in the 1960s. For a long time, it was just a theory. Scientists thought that solid helium might be able to become a supersolid if it was cooled down to extremely low temperatures, very close to absolute zero (the coldest possible temperature).

In 2004, some researchers thought they had found evidence of supersolid behavior in solid helium. However, later experiments showed that what they saw was actually caused by other effects, not true supersolidity.

It wasn't until 2017 that scientists finally created a true supersolid in a lab. They didn't use helium, but instead used special atoms called magnetic dipole atoms (like dysprosium or rubidium). They cooled these atoms down to super-low temperatures and used lasers to arrange them into a crystal-like structure, while also allowing them to flow. This was a big breakthrough in physics!

Why are Supersolids Important?

Supersolids are still a new and exciting area of research. Scientists are studying them to:

• Understand more about the fundamental rules of quantum mechanics, which describes how tiny particles behave.
• Explore new possibilities for materials with unique properties.
• Potentially develop new technologies in the future, although specific uses are still being explored.

Studying these unusual states of matter helps us learn more about the universe and how everything works at its most basic level.