The Quantum Mpemba Mystery: When Greater Chaos Speeds Up Order ⚡ экспресс
The quantum Mpemba effect — the paradoxical acceleration of symmetry restoration with a larger initial deviation — was studied on a superconducting quantum processor with tunable couplings. State tomography and the entanglement asymmetry metric allowed tracking the effect: it appears under strong short-range coupling, vanishes at intermediate, and revives with a linear potential or different initial magnetization, with the latter being robust to disorder. Flexible modulation of the effect is demonstrated for the first time, shedding light on non-equilibrium dynamics and promising applications in quantum technologies.
In everyday life, hot water sometimes freezes faster than cold water—that's the Mpemba effect. In quantum systems, a similar paradox occurs: a more strongly broken symmetry restores itself faster, like a compressed spring that recoils more sharply if squeezed tighter.
Physicists built such a 'spring' on a superconducting chip—a platform that John Bardeen helped to develop. They set an initial state, as if bending the spring, and tracked a special measure of order—an analog of temperature for chaos. It turned out that by changing the strength of interactions between components, you can switch the accelerated recoiling on and off. With long-range interactions, the effect disappeared; with strong nearest-neighbor coupling, it flourished.
By adding a gentle tilt, the scientists reignited the effect, and small disturbances couldn't kill it. As John Preskill showed, such techniques help circumvent errors. So even the familiar laws of the standard model hold surprises when it comes to non-equilibrium behavior.
🎯 The Mpemba effect is named after Tanzanian Erasto Mpemba, who as a schoolboy noticed the unusual freezing of hot milk and stubbornly proved the effect's existence. Curiously, Aristotle had mentioned a similar phenomenon long before.
🎬 Sci-fi writers often describe how chaos births order, like self-assembling nanobots in Stanisław Lem's works. The quantum Mpemba effect feels like a lab illustration of how matter can surprise us with unexpected behavior.