tunnel effect

Molecules in an ultracold gas are like tiny magnets: they attract when far apart, but when they get close they can stick together for good. Such sticking destroys the gas: particles drop out of the game, and you never reach the quantum regime where all of them behave as one.

Plasma is a gas in which electrons are stripped from atoms and roam freely. Sometimes, regions where electrons are almost absent spontaneously appear in such a gas; they are called holes. It is like a whirlpool forming in a stream, pulling everything around it in. But exactly how such a whirlpool is born has long remained a mystery.

When a fluid flows around an obstacle, it spawns vortices and shock waves. Describing their behavior means solving a nonlinear equation in which the flow velocity depends on itself. Classical supercomputers spend days on this, while quantum computers have barely been used: their native language is linear operations, but fluids are inherently nonlinear.

When a heavy atomic nucleus splits into two fragments, an invisible quantum thread remains between them. This thread is entanglement: the state of one fragment is instantly linked to the state of the other, as if they were still a single whole. For the first time, physicists have precisely calculated how long and strong such a thread can be, tracing the fission process step by step.

Two pebbles drop into water at a distance. The waves from them run toward each other and at certain spots they cancel out — the water becomes smooth, even though each stone alone would create ripples. Much the same happens with a pair of photons (light particles) born in a single crystal and flying off in different directions.

A superfluid gas is like a crowd of people marching in step: each atom knows where to go and doesn't fall out of the common rhythm. But this crowd has three 'valleys'—three different directions it can take. In a new experiment, physicists made one valley slightly more 'favorable' than the others and watched how the crowd darted between them.

A courier delivers packages to a building with two entrances. While the door is open, he freely enters both. But once one door starts to close, getting inside becomes harder and harder. That's roughly how information behaves at a black hole's horizon — the invisible boundary from which nothing can escape. In the new study, scientists described this process as two opposing flows.

A stone thrown at a wall bounces off. In the quantum world, a particle can pass right through, as if the wall were woven from mist. This is quantum tunneling: it lights up stars, works in microchips, and even operates in the cells of our bodies. But most particles have spin — an intrinsic rotation, like a spinning top.

A stone thrown at a wall bounces off. In the quantum world, a particle can pass right through, as if the wall were woven from mist. This is quantum tunneling: it lights up stars, works in microchips, and even operates in the cells of our bodies. But most particles have spin — an intrinsic rotation, like a spinning top.

Alice prepares a quantum particle in one of several states and sends it to Bob. The channel the particle travels through isn't perfect: it's noisy, scatters, interacts with the environment. Bob receives the signal and tries to figure out what Alice actually sent. This is the classic "prepare-send-measure" scheme, and there's always a risk of losing something along the way.

In the quantum world, particles sometimes behave like acrobats on invisible tightropes. An instanton field is a brief vortex that appears and vanishes in an instant. When a fermion (a particle like an electron) enters such a vortex, its energy does not stay put. Instead, it smoothly slides from one level to another, like a ball rolling down a hill.

A thin silver thread nearly as long as a hair's width, and inside it, pristine quantum laws hold sway. Physicists built a conductor where electrons can only move forward or backward, like on a perfectly straight single-lane road with no shoulders. On such a road, any pothole or pebble would normally destroy the fragile quantum state.

A neuron transmitting a signal is like a tiny battery that quickly discharges and recharges. For nearly 70 years, it was believed that a special "potassium valve," opening with a delay, was responsible for the recharge phase. New work claims this current is a ghost.

The quantum networks of the future resemble the Tower of Babel: each node speaks its own dialect. Some store information in the polarization of a photon — the direction of oscillation of the light wave. Others use time bins: that is, when exactly the pulse arrives.

The universe right after the Big Bang was like a boiling cauldron: bubbles of a new state of matter were bursting and growing everywhere. These were first-order phase transitions — exactly like water boiling, only at temperatures reaching trillions of degrees.

$$10^{-35}$$ seconds. A tiny instant during which the Universe manages to expand by a factor of $$10^{26}$$. Immediately after, it goes through thousands of rapid transformations — like a ball bouncing along a chain of tunnels. This cascade is the essence of chain inflation, first proposed by Alan Guth.

$$10^{-35}$$ seconds. A tiny instant during which the Universe manages to expand by a factor of $$10^{26}$$. Immediately after, it goes through thousands of rapid transformations — like a ball bouncing along a chain of tunnels. This cascade is the essence of chain inflation, first proposed by Alan Guth.

Empty space is not as empty as it seems. According to quantum theory, the vacuum is filled with particles that constantly pop in and out of existence. In 1976, physicist Bill Unruh showed that if an observer moves with acceleration, this 'quantum soup' turns into a genuinely warm bath for them — the Unruh effect.

In the early universe, as it cooled after the Big Bang, defects could have formed, like cracks in ice. One such defect is a global monopole, a tiny clump of field where energy is trapped in a knot.

A cold, black mirror — that's what the sea of dark energy, the invisible substance driving the expansion of the universe, looked like for billions of years. But the DESI spectrograph has caught a faint ripple.

The 21-kilometer ring near Protvino was once planned to accelerate protons. Today, the same tunnel could host a very different machine — a muon collider. The muon is a heavy cousin of the electron, and that's its strength. On a curve, an electron radiates like a searchlight, losing precious energy. A muon radiates a billion times less.

It all starts with a tiny scar — a thin tunnel connecting two universes. In quantum cosmology, there has long been discussion that our closed universe could have been born from "nothing" via tunneling (a process where a system overcomes a barrier that is insurmountable by ordinary standards).

Crystals fascinate us with their perfect spatial order: atoms frozen at lattice points, like beads on an invisible string. But what if the same symmetry unfolds in time? Time crystals are systems that, without any external cue, start repeating their states cyclically — clocks wound by nature itself. Inside this tireless rhythm, disorder seems to have no place.

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.

A false vacuum is not just a supercooled liquid, but a quantum hologram, ready to spring to life under the right projection. Its decay is described by the tunneling of a quantum field from a metastable minimum, and the classic calculation via Euclidean instantons is as elegant as a still life under spotlights.

Ever since Fritz Zwicky noticed that galaxy clusters were moving too fast, and Vera Rubin measured the rotation of spiral arms, dark matter has remained cosmology's greatest mystery.

Superconducting qubits are the beating heart of quantum computers, but their rhythm is disrupted by decoherence: quantumness dissolves into noise.

In quantum field theory, there is a long-standing mystery: infrared divergences. Usually they are seen as an annoying technical nuisance that must be carefully 'papered over' in calculations. But what if this is not a bug, but a feature?

The classical Mpemba paradox — hot water freezes faster than cold — has teased scientists for centuries. Only recently has nonequilibrium statistical mechanics explained it: it’s all about boundary conditions; the system seems to seek an excuse to “hit the wall” and speed up cooling.

A beam of light enters frosted glass and fades — nothing unusual. But physicists have long known how to make light pass through without losing a single photon. This trick is called electromagnetically induced transparency: two light waves cancel each other at the right point, and absorption disappears. Now a similar feat has been pulled off with atoms.

Quantum tunneling — the ability of particles to pass through barriers forbidden by classical physics — powers stars with thermonuclear fusion, ignites primordial nucleosynthesis, and gives us flash memory.

In the mid-20th century, physicists noticed something odd: the energy levels of complex atomic nuclei behaved like lottery balls — completely unpredictable. Since then, the search for such hidden chaos in the microworld has never stopped. Until recently, it was thought that chaos only appeared in systems that are constantly pushed, like a blender.

In the first moments of its life, the Universe resembled a boiling cauldron. As it cooled, phase transitions occurred — much like steam turning into water, but instead of molecules, the very state of space changed. In this cauldron, bubbles of the new phase were born, akin to bubbles in a pot coming to a boil.

In the world of magnetism, a simple dichotomy long reigned: ferromagnets, where spins point in one direction, and antiferromagnets, where they line up in a checkerboard pattern, canceling each other out. But a recent 'third player' — altermagnets — forced a rewrite of the rules.

Imagine a river at a rapid: the current accelerates until no wave can go against the flow. So it is with gas near a black hole: reaching the speed of sound, it locks itself in — an acoustic black hole is born, a twin of the gravitational abyss. Here the event horizon is woven from a flow faster than its own sound.

A ball sits in a pit. It won't roll out on its own: it needs a push. But in the quantum world, a particle can leak through a barrier without extra energy. This trick is called tunneling.

Plastic deformation is the language through which materials tell the story of their internal stresses. For almost a century, its grammar has been the theory of dislocations: tiny linear defects gliding through the crystal lattice and carrying shear.

The hot broth of the early universe cooled unevenly. At some point, bubbles of a new phase began to pop within it, like steam bubbles in boiling water. But these bubbles weren't made of steam; they were made of a new state of matter in which particles of the dark sector clumped into larger lumps. That's how dark matter could have been born.

A stone falls into water, and ripples spread in all directions. Throw a handful of stones at once, and the ripples overlap: you can no longer tell which ripple came from which stone. A neutron beam hitting a detector looks much the same: a bright spot blurred by many causes.

Toss a handful of phosphorus into silicon, and at a certain impurity concentration the material suddenly starts conducting electricity. This is a metal-insulator phase transition, and it happens abruptly. But what exactly changes in the electron wave functions when an insulator becomes a metal?