Researchers in Australia predict new form of quantum matter

MELBOURNE — Researchers in Australia have predicted a new type of quantum matter, challenging decades of thinking about how ultracold particles behave.

The study shows that under the right conditions, mixtures of two fundamentally different types of quantum particles -- bosons and fermions -- can form stable, self-bound "quantum droplets," according to a statement released Monday by Australia's Monash University.

Until now, scientists believed these exotic droplets were unlikely to exist in strongly interacting Bose-Fermi systems, according to the study, published in Physical Review Letters with collaborators from Heidelberg University in Germany.

Researchers said the discovery provides a new theoretical roadmap for experiments around the world and could deepen understanding of quantum materials that underpin future technologies, from ultra-precise sensors to quantum computing, reports Xinhua news agency.

Lead author Sam Foster, a PhD candidate at Monash University's School of Physics and Astronomy, said the findings open the way to exploring new quantum states and address a long-standing theoretical challenge.

"These two very different types of particles could balance each other perfectly to create a stable droplet that effectively holds itself together," Foster said, adding that previous theories could describe such systems only when particles interacted relatively weakly, while the new approach allows researchers to explore stronger interactions where more complex physics emerges.

The study found that unlike an ordinary liquid droplet, a quantum droplet exists because of the strange rules of quantum mechanics. In this case, an attractive force between the particles is exactly balanced by the pressure generated by the fermions, preventing the system from collapsing.

The team found the predicted droplets should be achievable using existing ultracold atom experiments, making experimental confirmation a realistic next step.