Quantum breakthrough: Physicists have discovered a new and unusual state of matter.

Physicists have for the first time confirmed the existence of a peculiar quantum state of matter known as counterflow superfluidity. In this state, two distinct components, such as different types of atoms, flow in opposite directions with perfect correlation. Although both components are superfluid, the system as a whole remains stationary and incompressible. Physicists believe that counterflow superfluidity will aid in better understanding and modeling complex quantum systems in extremely cold environments and will serve as a foundation for further discoveries in quantum physics. The research has been published in the journal Nature Physics, as reported by Interesting Engineering.

For the past 20 years, physicists have predicted the existence of counterflow superfluidity. However, until now, scientists have not been able to observe this unusual state of matter during experiments.

Superfluidity itself refers to the ability of matter in a quantum fluid state, which occurs when atoms are cooled to nearly absolute zero (-273.15 degrees Celsius), to flow without friction. Superfluidity was first discovered in the 1930s in liquid helium. This discovery led to the development of many low-temperature technologies, such as laser cooling. The authors of the new study believe that the discovery of counterflow superfluidity will also have significant implications for the creation of new quantum technologies and may lead to new breakthroughs in quantum physics.

To discover counterflow superfluidity, physicists prepared a two-component system using rubidium-87 atoms cooled to nearly absolute zero, which had different spin states, or intrinsic angular momentum. The atoms were then exposed to laser light that held the atoms in specific positions.

This resulted in the formation of a Mott insulator, a material that, in theory, should conduct electricity, but actually does not. This occurs because strong interactions between the spins of its particles cause them to localize, preventing electrons from moving freely.

By controlling the interactions between atoms in the quantum system, physicists were able to alter the extremely cold state of matter and achieve a state in which two types of atoms flowed in opposite directions. However, they remained perfectly balanced, thus demonstrating the presence of counterflow superfluidity.

Using a quantum gas microscope, physicists were able to observe individual atoms in the system and confirmed that they were in opposite states.

The observation confirmed that when one atom moves in one direction, another atom with an opposite spin state moves in the opposite direction.