particle antiparticle pair

The antiproton is the mirror twin of the proton: same mass, but negative charge. When it hits matter, it usually annihilates instantly — disappearing in a burst of energy upon colliding with an atomic nucleus.

The atomic nucleus isn't always round like a billiard ball. Some nuclei stretch out like a rugby ball, while others become pear-shaped — with one end thicker than the other.

In 2021, the LHAASO observatory registered gamma quanta with energies above a petaelectronvolt from sources like the Crab Nebula — a supernova remnant with a pulsating neutron star at its heart.

Quantum entanglement — a phenomenon where the states of two or more particles become interconnected regardless of the distance between them — usually links intrinsic properties such as spin or polarization. However, a new experiment has for the first time realized entanglement of the positions of two atoms in space.

Twins enter a room from different doors. Each gets a box with a button, and each time they press it, either a red or a green light flashes. If the twins are perfectly identical, you'd expect their lights to follow the same internal rules. But what if the rules differ even though the twins are exact copies? That's precisely the scenario the authors explored.

In very dim light, photons arrive one by one, like drops from a leaky faucet — never in pairs. This effect, predicted by Roy Glauber and confirmed by Leonard Mandel, directly proves that light is made of particles.

Two massive spheres slowly drift apart in empty space. From the standpoint of ordinary mechanics, nothing special is happening. But Einstein's equations say otherwise: accelerating masses stir spacetime itself, and from them spread gravitational waves — ripples that stretch and squeeze everything in their path.

Light falling into a black hole carries information — for instance, the path a photon took. The horizon (the surface from which nothing returns) responds by changing its entropy — a measure of disorder, akin to the number of shuffled pages in a book.

Physicists have proposed an experiment: a laser beam acts as a quantum detector and splits into two beam-ears. Each ear is directed through a tiny cloud of ultracold atoms — in this state, atoms merge into a single wave.

A stone falls into a pond — ripples spread across the water. If the stone doesn't fall but whizzes over the surface at tremendous speed, a straight wave runs along the water. When it hits a floating log, ripples spread out from the point of impact. That's roughly how gravity works in the new study.

A pinch of salt falls into water, and sodium and chlorine ions scatter, surrounded by water molecules. Now, instead of an ion, a positron (an antiparticle, the electron's twin but with a plus instead of a minus) joins the molecular crowd.

A handful of rice thrown into a glass of water scatters — the grains spread apart. Now imagine each grain propels itself forward with stubborn persistence and bounces off softly upon collision. Such particles are called active: they spend their own energy to move, like bacteria or microscopic robots.

To uncover the proton's true size, physicists swapped the electron in a hydrogen atom for its heavy copy — the muon. Acting like a magnifying glass with thousandfold power, the muon gets right up against the nucleus and 'probes' the proton with unprecedented precision.

A ring road around the Sun, where the traffic is not cars but clumps of matter. The diameter of this road is measured in light-years: it encircles our planetary system at its outer edge, in the Oort Cloud, where the star's weak gravity still holds sway.

In the first instants after the big bang, the universe was a quantum vacuum where pairs of particles and antiparticles, virtual "guests" from physical nothingness, spontaneously appeared and almost immediately annihilated.

The universe wasn't born alone — alongside it came a mirror twin where everything is reversed: left and right are swapped and time flows from future to past. After the Big Bang, the world, according to Alan Guth's idea of superfast inflation, should have contained equal amounts of matter and antimatter.

Two tiny emitters, each about the size of an atom, can together do what neither can do alone. We're talking about light scattering — when light hits particles and bounces off in all directions. Usually, a pair of particles scatters light only slightly more than a single one.

The Large Hadron Collider doesn't just smash protons: it also collides entire atomic nuclei. When two nuclei smash together at tremendous speed, they create a tiny blob of matter so hot that protons and neutrons melt into a 'soup' of quarks and gluons.

At Hungary's Institute for Nuclear Research, ATOMKI, physicists noticed something odd: in the decays of excited atomic nuclei, pairs of electrons and positrons sometimes fly apart at an unusual angle. It's as if an invisible mediator particle briefly appears and disappears between them.

A pebble drops into a pond, and ripples spread across the water. But sometimes the pebble doesn't sink right away: it skims beneath the surface, travels a few meters, and only then surfaces, creating ripples in an unexpected spot.

Two particles cling to each other like climbers on the same rope and fly toward a wall. When they hit, will they bounce off together, or will the rope snap? What does it depend on? Physicists considered the simplest case: everything happens on a single line, the particles attract only when they occupy the same point, and the wall is perfectly rigid.

Two water droplets tremble in sync — because they're connected by a straw. So it is with entangled particles: their unity may be held together by a microscopic wormhole.

Light consists of portions — photons. Max Planck was the first to understand that light is emitted in quanta. Today, we can guide single photons. When such a photon encounters a fast shutter, it cannot be sliced — half a photon doesn't exist. Instead, a quantum mixture of states with different photon numbers emerges: zero, one, two, three..

In 1935, Einstein, Podolsky, and Rosen proposed a thought experiment that, in their view, exposed the incompleteness of quantum mechanics. Two particles fly apart after interacting, and measuring the momentum of one instantly gives exact knowledge of the other's momentum.

Two vessels of water at different temperatures are separated by a thin partition. As long as the partition is intact, each vessel lives its own life: in one, the water is hot; in the other, it's icy. But once the partition is removed, the temperatures begin to equalize, and eventually both vessels reach the same state.