Quantum vortices – tiny whirlpools in the quantum fluid – cause the precession and revolution of the superfluid crystal structure to synchronise their motion. Credit: Andrea Litvinov.
New research shows supersolid, an exotic form of quantum matter, synchronises under rotation unlocking quantum insights.
A supersolid is a paradoxical state of matter – it is rigid like a crystal but flows without friction like a superfluid.
This exotic form of quantum matter has only recently been realised in dipolar quantum gases.
Researchers led by the University of Innsbruck’s Francesca Ferlaino set out to explore how the solid and superfluid properties of a supersolid interact, particularly under rotation.
In their experiments, they rotated a supersolid quantum gas using a carefully controlled magnetic field and observed a striking phenomenon.
Ferlaino said: “The quantum droplets of the supersolid are in a crystal-like periodic order, all dressed by a superfluid between them.
“Each droplet precesses following the rotation of the external magnetic field; they all revolve collectively.
“When a vortex enters the system, precession and revolution begins to rotate synchronously.”
Surprise
Theoretical modelling lead Elena Poli said: “What surprised us was that the supersolid crystal didn’t just rotate chaotically.
“Once quantum vortices formed, the whole structure fell into rhythm with the external magnetic field – like nature finding its own beat.”
Andrea Litvinov, who conducted the experiments, added: “It was thrilling to see the data suddenly align with the theory.
“There was a moment when the system just ‘snapped into rhythm’.”
A new probe for quantum matter
Synchronisation is when two or more systems fall into rhythm with each other.
It’s common in nature – like pendulum clocks ticking in unison, fireflies flashing together, or heart cells beating in sync.
The Innsbruck team showed that even exotic quantum matter can synchronise.
The discovery not only deepens understanding of this unusual state of matter but also offers a powerful new way to probe quantum systems.
By tracking synchronisation, the team was able to determine the critical frequency at which vortices appear – a fundamental property of rotating quantum fluids that has been difficult to measure directly.
The team combined advanced simulations with delicate experiments on ultracold atoms of dysprosium, cooled to just billionths of a degree above absolute zero.
Using a technique called ‘magnetostirring’, they were able to rotate the supersolid and capture its evolution with high precision.
From the lab to the cosmos
The findings could have implications beyond the laboratory.
Similar vortex dynamics are thought to play a role in sudden ‘glitches’ observed in neutron stars, some of the densest objects in the universe.
Poli said: “Supersolids are a perfect playground to explore questions that are otherwise inaccessible.
“While these systems are created in micrometre-sized laboratory traps, their behaviour may echo phenomena on cosmic scales.”
Group leader Ferlaino added: “This work was made possible by the close collaboration between theory and experiment – and the creativity of the young researchers on our team.”
The study is published in Nature Physics.
