double slit experiment

In a ring-shaped channel between two toothed rings, microspheres are suspended: some with a radius of 8 micrometers, others 14. The discharge is switched on, and the particles start moving. The small ones go one way, the large ones the other. It is like a shopping mall where escalators for people of different heights run in opposite directions.

A storm in the upper atmosphere lasts a few millionths of a second. A cosmic ray, a proton or a helium nucleus, strikes air molecules, sending a swarm of particles downward. Most of them stay together, but occasionally one particle gains so much energy that it surges ahead.

A polar molecule is like a tiny dumbbell with opposite charges at its ends. Normally, such particles quickly stick together or fly apart when they meet — electric forces are too strong. But the authors of the work found a way to turn this aggressiveness into a controlled game.

A carousel doesn't just spin you around in a circle — with each revolution, it also slightly screws itself into the ground. This corkscrew-like motion is the essence of the NUT charge, a special property of spacetime that physicists have been studying since the mid-20th century.

Every quantum particle has spin — an intrinsic magnetic property, like a tiny arrow. In an experiment, a beam of such particles passing through a magnet splits in two, like a coin that lands either heads or tails. That’s exactly how particles like a hydrogen atom behave.

Two parallel streams of atoms, released from Bose condensates, begin their journey in free fall. In the classical picture, their separation remains unchanged — like two skiers gliding down a perfectly smooth slope. But if spacetime is not frozen snow, but a living, rippling membrane, then every tremble of it is transmitted to matter.

A deuterium molecule, two atoms of heavy hydrogen, falls apart under a laser pulse. One electron is ripped away, leaving an ion behind. At that moment, they are still linked: the direction of one immediately tells you which way the other went. This link is called quantum entanglement.

A sheet of graphene one atom thick is like a perfectly smooth tablecloth on which electron marbles roll. Place an electric barrier in their path, and usually they'll bounce back. But in graphene, it's different: under certain conditions, electrons pass through the barrier without even noticing it, as if the wall were made of mist.

In turbulent air, droplets don't fly in straight lines: they get tossed around like dust motes in a beam of light. Physicists have built a setup that tracks each droplet, which is about a tenth of the thickness of a human hair. A camera captures their motion, and a computer reconstructs their trajectories.

Drop two pebbles into a pond: each sends out ripples, and on the water you'll see crests where waves reinforce each other and troughs where they cancel. Protons behave much the same way: when there are two, they create a double ripple that adds up into a recognizable pattern.

Light from a single source can be made to 'meet' itself, and then fringes appear on the screen, like ripples from two pebbles dropped into water. Physicists have long known how to do this with two photons, but making four particles of light merge at once was tricky: single-photon sources lost too many particles along the way.

In the quantum world, particles do not have precise properties until they are measured. The official model refuses to explain what lies behind this uncertainty. But the idea that invisible 'pilots' control particles has been around since the 1920s.

In the first moments after the Big Bang, the Universe underwent rapid expansion: inflation. But perhaps it was contracting before that, and then bounced. Both scenarios leave nearly identical imprints on the cosmic microwave background, and cosmologists have debated for decades which one is correct.