Finnish Physicists Wire Up a 'Time Crystal' to a Real Device for the First Time

Physicists in Finland have for the first time connected a time crystal — an exotic form of quantum matter that ticks forever without consuming energy — to an external mechanical device, a breakthrough that researchers say opens a credible path toward ultra-precise sensors and far more stable memory for quantum computers.

A team at Aalto University's Department of Applied Physics, led by Academy Research Fellow Jere Mäkinen, reported the result in the journal Nature Communications. Their experiment used a swarm of magnetic quasiparticles called magnons, injected into a chilled vat of superfluid helium-3 cooled to within a thousandth of a degree of absolute zero. Under those extreme conditions, the magnons spontaneously organized themselves into a so-called magnonic time crystal — a quantum state whose internal rhythm repeats indefinitely without any external energy input. The Aalto team then coupled the system to a vibrating mechanical resonator, effectively converting the time crystal into what physicists call an optomechanical device.

"Perpetual motion is possible in the quantum realm so long as it is not disturbed by external energy input," Mäkinen said in a statement released by the university. "Time crystals last for orders of magnitude longer than the quantum systems currently used in quantum computing." That longevity is what excites quantum engineers. Today's superconducting qubits, the building blocks of machines from IBM, Google and IonQ, lose their fragile quantum state — a process called decoherence — in microseconds to milliseconds. A time crystal, by contrast, can preserve its phase relationship essentially forever, provided it remains isolated from environmental noise.

The concept of a time crystal was first proposed by Nobel laureate Frank Wilczek of MIT in 2012 and was dismissed by many physicists as a theoretical curiosity that violated the second law of thermodynamics. That objection was resolved in 2016 when researchers showed that so-called Floquet time crystals, driven by periodic external forces, were compatible with thermodynamics. The Aalto experiment goes a step further by producing a discrete time crystal in equilibrium with its environment — and then, crucially, by hooking it up to a device that can read its rhythm and respond.

For sensors, the implications are profound. Because the time crystal's oscillation frequency is set by the underlying physics of the magnon condensate rather than by any external clock, it can act as an exquisitely sensitive frequency reference. Mäkinen's team estimates that a mature device could outperform the best atomic clocks at detecting tiny perturbations in magnetic fields, making it useful for everything from gravitational-wave detectors to medical imaging. "You can think of this as connecting an ideal pendulum to the outside world without slowing it down," said co-author Vladimir Eltsov, a senior scientist at the university's Low Temperature Laboratory.

Independent physicists called the result a genuine milestone but cautioned that practical devices remain years away. The Aalto apparatus operates at temperatures only millikelvins above absolute zero — colder than anywhere in the known universe — and a usable consumer technology would require room-temperature time crystals, a goal researchers are still chasing. "This is the first time anyone has read out a time crystal's signal through a coupled mechanical mode," said Norman Yao, a physicist at Harvard who reviewed the paper. "It moves time crystals from an exotic curiosity into the toolkit of experimental quantum technology." The Aalto group, which is funded in part by the European Research Council and the Academy of Finland, has already begun work on a second-generation device that they hope will sustain coherence for hours at a stretch.