non equilibrium state

A thin film of neodymium nickelate, fifteen nanometers thick, sits on a neodymium gallate substrate. Below one hundred eighty kelvin it behaves as an insulator: electrons are locked inside their atomic cells and cannot move freely.

In a pot of water carefully heated above its boiling point, the liquid remains calm. But the slightest disturbance, and it violently turns to steam. Physicists call this a metastable state: it seems stable, but in reality it's ready to break apart at the slightest nudge.

Hot water sometimes freezes faster than cold. Ice forms more quickly from boiling water. This paradox, discovered by schoolboy Erasto Mpemba, long puzzled physicists. It turns out: the farther a system is from equilibrium, the faster it relaxes back to it. The Mpemba effect remains controversial today: too many variables, hard to reproduce.

In a glass of water, oil gathers into droplets: that's equilibrium separation dictated by chemistry. But there are systems where order arises not from rest but from a constant flow of energy.

A runner trails the leader but crosses the finish line first. In the quantum world, such a trick was pulled off by a system of nuclear spins — tiny magnetic arrows of carbon-13 atoms in a diamond. This is a manifestation of the Mpemba effect: a state initially farther from equilibrium settles down faster than one closer to rest.

Imagine a slide with three dips: the deepest one is a stable position for a ball, the middle one is precarious. A slight push and the ball rolls down. Yet, constant vibration of the right strength can hold it in the middle hollow for a long time. In the 1950s, physicists Lee and Yang discovered that all states of matter are separated by invisible points in the world of imaginary numbers.

An eternal Universe where the measure of disorder (энтропия) grows is, for most of its time, a homogeneous void. In it, complex structures occasionally assemble by chance, such as fleeting consciousnesses — ‘мозги Больцмана’.

Time crystals are quantum phases of matter that spontaneously oscillate, like a tuning fork with an infinitely decaying echo. If an ordinary spatial crystal repeats an atomic pattern in space, breaking translational symmetry, a time crystal exhibits periodicity in time, breaking time translation symmetry.

Since time immemorial, physicists have dreamed of tunnels piercing the cosmos — wormholes, capable of connecting far-flung corners of the Universe in an instant.

The core of a neutron star can be likened to a taut string of super-nuclear density. Sound traveling along it is the oscillation of pressure, whose speed $$c_s$$ betrays the stiffness of matter. New research shows that this cosmic string does not hum monotonically.

A quantum battery is not a box of chemicals but a chain of tiny magnets (spins) capable of storing energy. Its main trick: charge many particles at once, using their quantum entanglement. But there's a catch — not all entanglement works.

A pot of water has just been stirred: the whirlpools and eddies gradually calm down, and the liquid becomes smooth. A similar process, but in the quantum world, occurs in superfluid helium or in a cloud of ultracold atoms.

The quantum world is like an orchestra where each musician, a particle, plays their part, and together they create a harmonious symphony. But as soon as noise, random clicks and interference, enters the hall, the melody starts to drift.

A quantum dot is a box so small that an electron inside cannot have just any energy, but only strictly defined values, like the steps of a staircase. Each step can accommodate several electrons, but exactly how many is the question. If a step is double, two electrons can stand on it; if single, only one.

A thin film of metal oxide lies on a surface with a tiny pit. If you gently compress the film from the sides, it won't crumple — instead, it will bow downward into the pit or bulge upward like a hump. Both positions are stable, like a canning jar lid that is either concave or convex and doesn't flip back and forth on its own.

Cooling usually brings order: water freezes into ice. But in the quantum world, order takes unexpected forms. Experimenters cooled polaritons — particles that are both light and matter — to near absolute zero.

Ice cubes in a glass melt, and the water mixes on its own. Many quantum systems behave this way: particles exchange energy, and after a while, order disappears. But if you add a spoonful of honey to the glass, mixing slows down, and in intense cold, the water freezes into glass — without a crystal lattice, but also without flow.

Intelligent action begins with a plan. Just as an architect needs blueprints to evaluate options, any agent with will needs to repeatedly copy data about reality.

A wave rolls onto the sand, leaving a pattern of foam and shells. A moment later it recedes, but the traces are no longer the same: the sand is smoothed, the shells are flipped over. Something similar happens in the quantum world when a system moves from a nonequilibrium state toward equilibrium.

Imagine a house of cards where each card supports the others. One wobbles, and the neighbors start to lean. Earth's climate system works similarly: ice sheets, ocean currents, tropical forests, all are connected. If one element crosses a threshold, it can drag the rest down with it.