Strange quantum effect can make matter invisible

A strange quantum effect predicted decades ago has finally been demonstrated. If you make a gas cloud cold and dense enough, you can make it invisible. This technique can be used to prevent information loss from quantum computers.

Scientists at the Massachusetts Institute of Technology (MIT) in the US used lasers to squeeze and cool lithium gas to a density and temperature low enough that it scatters less light. If they can cool the gas cloud to -273.15 degrees Celsius, they say it will be completely invisible.

The blue laser light used in the Pauli blocking experiment renders matter invisible.

This strange effect is the first concrete example of the quantum mechanical process known as the Pauli blocking process.

"This is the first clear observation that this effect exists, and it suggests a new phenomenon in physics," said senior author Wolfgang Ketterle, a professor of physics at MIT.

This new technique could be used to develop light-blocking materials to prevent information loss in quantum computers.

The Pauli intercept comes from the Pauli exclusion principle, first postulated by the famous Austrian physicist Wolfgang Pauli in 1925. Pauli holds that all so-called fermions - such as protons, neutrons and electrons - having the same quantum state cannot exist in the same space.

The exclusion principle also applies to atoms in a gas. Normally, the atoms in a gas cloud have plenty of space to bounce around, but still have enough energy levels for them to jump in and not significantly impede their motion.

At the time, the researchers explained, they were stacked on top of each other. They are so packed that the particles cannot interact with light. The incoming light is intercepted by Pauli and will pass straight through.

But bringing a cloud of atoms to this state is difficult. Not only does it require extremely low temperatures, but it also requires the atoms to be extremely tightly pressed.

Two other independent groups have also cooled two other gases, potassium and strontium, to show this effect. In the strontium experiment, the researchers blocked excited atoms to keep them in an excited state for longer.

Finally, the researchers demonstrated the Pauli blocking effect and could use it to develop light-blocking materials. This would be particularly useful for improving the efficiency of quantum computers, which are currently hampered by quantum coherence depletion - the loss of quantum information (carried by light) to the medium. around the computer.