For the first-time ever, a team of researchers from the University of Queensland cooled a special form of quantum liquid - a superfluid - using a laser light. Although lasers are frequently used to cool gases and solids, until now they have never before been used to cool a quantum liquid.
Superfluids are quantum liquids that, like electrical currents in superconductors, have a unique property that allows them to never stop flowing. This property is one of the main reasons that scientists are eyeing superfluids for use in various proposed applications.
"The applications of this research range from improved sensors for navigational systems to the development of quantum devices and fundamental exploration of the quantum physics of turbulence, or the turbulent motion of quantum fluids when cooled to temperatures close to absolute zero," said Glen Harris, lead author of the study.
In the current experiment, the team created a superfluid helium film on a silicon chip and subsequently used a laser light beam to gather energy out of the waves on the surface of the superfluid, leading to their cooling. Furthermore, the team also revealed that combining superfluid with microphotonics can help scientists achieve very precise superfluid wave measurements.
Warwick Bowen, chief investigator of the experiment, claims that the findings will help scientists in the field get closer to creating new inertial systems that can be used in navigation systems.
"Previous experiments have shown that ultra-precise inertial sensing is possible using superfluid helium," he said. "However, these experiments relied upon bulky architectures somewhat akin to a plumbing system for water. The ability to cool, measure and control superfluid waves on a silicon chip brings a new level of scalability and integrability to such sensors."
The results - which stem from the collaboration between an international team of researchers from Australia, New Zealand, France, Belarus and Ireland - come just a day after the discovery of a new state of matter called a quantum spin liquid.
Scientists are hopeful that this finding will lead to the creation of quantum computers and, in combination with the current laser cooling study, numerous potential advancements in the field could become a reality.
The findings were published in the April 5 issue of Nature Physics.
