Posted: Nov 21, 2021 17:20 GMT
The technique could be used to stop the loss of information from quantum computers.
A strange quantum effect that was predicted decades ago has finally been demonstrated: if a gas cloud is made cool and dense enough, it can become invisible. This strange effect is the first specific example of a quantum mechanical process known as Pauli lock.
Scientists at the Massachusetts Institute of Technology (MIT) used lasers to compress and cool lithium gas to low enough densities and temperatures to scatter less light. By cooling the cloud even closer to absolute zero (-273.15 degrees Celsius), this becomes completely invisible. The results were published this Thursday in the journal Science.
“What we have observed is a very special and simple form of Pauli blockade, which consists of preventing an atom from doing what all atoms would naturally do: scattering light,” the lead author of the study said in a statement. Wolfgang Ketterle, MIT professor of physics. “This is the first clear observation that this effect exists, and it shows a new phenomenon in physics,” he added.
The Pauli block comes from Pauli exclusion principle, first formulated by the famous Austrian physicist Wolfgang Pauli in 1925. He argues that all particles called fermions (such as protons, neutrons, and electrons) with the same quantum state cannot exist in the same space. Without the exclusion principle all the atoms would collapse together while erupting in a huge release of energy.
Invisibility of matter
As atoms are cooled they lose energy, filling all the lowest available states and forming a type of matter called fermi sea. The particles are locked into each other, unable to go to other energy levels. At this point, they pile up in melee and have nowhere to go if hit. They are so stacked that the particles can no longer interact with light. Therefore, the light that is sent inside complies with the Pauli blockade and will simply pass through, the researchers explain.
According to the study, it is complex to get an atomic cloud to reach this state. Not only does it need incredibly low temperatures, it also requires the atoms to be squeezed to record densities. After trapping its gas inside an atomic trap, the researchers blew it up with a laser. As theory predicted, the cooled and compressed atoms scattered 38% less light than those at room temperature, making them much weaker.
Now that researchers have finally demonstrated the Pauli blocking effect, they could use it to develop materials that suppress light to avoid information loss in quantum computers.
Add Comment