Quantum Mpemba effect: hot cools faster, but only near absolute zero ⚡ экспресс
The Mpemba effect — when hot water freezes faster than warm — is like a runner who starts behind but reaches the finish line first. In a new study, scientists added quantum rules and saw that at ultralow temperatures, this effect works in a new way, and even a reverse freezing order emerges. What else does the cold hide?
The Mpemba effect is a mystery where hot вода sometimes freezes faster than warm water. Usually this is attributed to how вода loses heat and энтропию (a measure of disorder). But in a glass of water, chaos prevents a precise model.
Physicists built a quantum model: a particle in a well with two depressions separated by a barrier. Like a ball on a hill with two dips: to roll from one to the other requires energy. In classical physics, a hot ball jumps more often. In the quantum world at ultra-low temperatures, the particle spreads into a wave and seeps through the barrier – without heating.
Surprise: the quantum Mpemba effect manifests not at room temperature, but only near absolute zero, where liquid гелий is used. Hot cools down faster, but only when thermal motion halts. Moreover, reverse paradoxes arise: cold overtakes hot, and sometimes a double reversal is observed – phenomena impossible in everyday life.
🎯 The effect is named after Tanzanian schoolboy Erasto Mpemba, who in 1963 noticed that hot ice cream mix freezes in the freezer faster than cold, and convinced physicists of this.