hysteresis

In a hot mug, water sometimes freezes faster than in a warm one. This paradox is over half a century old and is called the Mpemba effect. It is usually attributed to fluid motion or evaporation. Now physicists have shown that a similar trick is possible without water, just through radiation of heat.

A tightly stretched sheet lies on a table for days. Outwardly it's still, but the fabric fibers retain tension — loosen one edge slightly, and wrinkles will run across it, rearranging the whole pattern. That's roughly how a layer of epithelial cells behaves at rest. It doesn't just freeze; it accumulates mechanical stress — a kind of cellular memory of past movements.

If you squeeze an ordinary piece of metal, it heats up — even those who have pumped a bicycle tire know that. But what happens if you squeeze a magnet in which atomic arrows refuse to freeze even at absolute zero?

A ball on a slope with two pits usually rolls into the nearest one and comes to rest. But if the slope is slightly deformed and 'remembers' recent nudges, the ball can hang around halfway for a long time — in a narrow spot it doesn't want to leave. That's exactly the trick physicists played with light.

An ordinary phone battery breathes — not with air, but with contact. Inside a solid body, where there are no liquids, lithium presses against the electrolyte (the ion-conducting substance) during charging and pulls away during discharging, like a lung on inhale and exhale. This 'breathing' is not poetry but physics: each cycle creates and destroys the contact points through which current flows.

Every group has its unspoken trios: three friends who are always together. And there are pairs that exist on their own. It turns out that how much trios "contain" pairs determines how everything, from a virus to a new idea, spreads through the group. Scientists introduced a measure they call the nesting coefficient.

Erasing a single bit of information isn't free. In 1961, Rolf Landauer showed that at room temperature, it takes at least about 3 zeptojoules of energy — a tiny but nonzero amount. This limit was considered as ironclad as the conservation of energy. But what if you could give the system a little nudge?

Metals are full of free electrons: they dart between atoms like a swarm of bees around a hive. If you poke such a metal with a thin magnetic filament, the electrons start to feel its field. A new calculation shows they don't just go around the field; they trap it inside, like a cork sealing water in a bottle.