Scientists have long been trying to reach absolute zero, the coldest theoretical temperature. At normal room temperature, atoms are moving constantly, but at absolute zero, atoms are completely still.
Absolute zero is zero degrees on the Kelvin scale, or -459.67 degrees Fahrenheit and -273.15 degrees Celsius. Researchers from the University of Sussex have reached within a millionth of a degree of absolute zero—closer to this temperature than ever before.
What Are Atoms?
Atoms are made of protons, neutrons, and electrons. Protons and neutrons are found in the nucleus or the center of the atom. Electrons orbit the nucleus, just like planets orbit the sun. There are different levels that electrons sit on called shells.
In space, planets cannot jump off their orbit on to another planet’s orbit, but electrons can. It takes energy to excite the electron to move up to the next shell. The amount of energy it takes is called “bandgap.”
How Do Scientists Reach Such Extreme Temperatures?
Scientists exploit bandgap to freeze electrons. If energy is exerted on the atom, it will want to use it as an opportunity to excite an electron. Therefore, if the exerted energy is less than one bandgap, the atom will use some of its own energy in order to excite the electron.
Scientists say that an atom’s energy is in the form of heat: if it gets energy, it will gain heat, and if it loses energy, it will lose heat. When an atom uses some of its own energy to excite an electron, it will have less energy than it started out with. Because the atom’s energy is in the form of heat, it will lose heat and become cooler.
The important part of this process is that atoms be given less than one bandgap of energy, forcing them to expend their own energy to excite electrons. Instead of using lasers, these scientists simplified the task by using microwaves because the waves that they make are easier to produce than lasers. Usually, people think of microwaves as things that heat food up. This is not the first time microwaves are used for cooling, but this is the lowest temperature ever reached by microwaves.
What Could This be Helpful For?
The study of physics of atomic particles is called quantum physics. The ability to freeze atoms to absolute zero is a huge advancement in quantum physics. With more research, scientists hope to gain great experimental control over molecules. In the future, we might be able to create tools like quantum computers, which would be faster than traditional computers and could solve complicated math equations very quickly.