Zeeman effect

In a quiet room with no magnets anywhere, two electrons in a silicon trap still feel a faint trembling. It comes from the nuclei of silicon and germanium atoms, which spin randomly like the needles of broken compasses. This trembling was once considered noise, but now it has become a measuring instrument itself.

A magnetic vortex is like a tiny whirlpool in the sea, except that instead of water, it's magnetization that swirls. Such vortices could become memory cells in future computers, but to write and read information, you need to be able to move each vortex individually. So far, this is done crudely — shifting a whole bunch at once.

An X-ray flash tears through matter in billionths of a second. To remember it, physicists make atoms briefly absorb the light and then release it back. But pulling out a photon on command is like grabbing the right book from a shelf when the shelves move on their own. The usual approach is to move several absorbers with extreme precision, like a well-coordinated orchestra.

A weak laser beam falls onto a tiny structure — a hybrid cavity made of metal and glass. Inside is trapped a single light-emitting molecule. Normally, such light only slightly changes color as it scatters off thermal vibrations of atoms.

Ion current through a membrane is like a queue at a turnstile. Sometimes the turnstile is free — ions pass through quickly. Sometimes it gets stuck — the flow drops. A weak magnetic field, it turns out, doesn't push ions from behind; it simply changes the number of open turnstiles.

Radio astronomy began with the mysterious noise caught by the antenna of Karl Jansky and the rhythmic pulses that Jocelyn Bell Burnell playfully called 'little green men'.

The early Universe was like a rapidly cooling ocean. At colossal temperatures, everything was one — quarks, electrons, forces all blended into a symmetric 'steam.' But as it expanded and cooled, this steam condensed, phase transitions cascading one after another like water turning to ice.

In the vast clouds of rarefied gas that fill the space between stars, something is always churning. Supernova explosions, colliding streams — all of it shakes the plasma. And in this rippling, as it turns out, hides the mechanism that gives birth to magnetic fields. Plasma is a gas in which electrons are stripped from atoms.

In a crystal that for centuries was called 'fool's gold,' physicists have spotted genuine treasure. The compound MnTe2 with a pyrite structure has become the stage for a quantum ballet: spin waves here twist into left- and right-handed vortices, with the twist direction firmly tied to momentum.

Building a quantum network node is like teaching a dancer to balance on a carbon thread over an abyss. One leg must spring lightly from the wire, hurling photon-messengers into the external world. The other must grip the rope tightly, guarding precious quantum information.

Space is threaded with magnetic fields. They exist around galaxies, stars, and even in nearly empty voids — the vast empty spaces between galaxy clusters. It's usually thought that fields are amplified from weak 'seed' fields by turbulence, much like a dynamo. But the origin of the seed fields themselves has remained a puzzle.

Light from a distant blazar, an active galactic nucleus whose jet points our way, travels for billions of years. Along the way, it triggers cascades of charged particles that the intergalactic magnetic field deflects sideways. This creates a blurred gamma-ray glow around the blazar: a secondary halo.

In 1905, Einstein showed that the chaotic motion of pollen in water results from the jostling of invisible molecules. A century later, physicists have learned not only to observe but also to control motion at the quantum level.

A juggler tosses clubs while sitting on a spinning chair. If he starts spinning the clubs all in one direction, the chair will rotate the opposite way — otherwise, the conservation of angular momentum would be violated.

A vast, dark cloud of gas stretched across the young universe. Inside it, like invisible fingers, magnetic field lines left over from the very birth of the cosmos threaded through. These fields act on charged particles, pushing them together, like a gentle breeze gathering fallen leaves into piles.

An invisible film, a quantum field, is stretched over a rubber bagel. While the bagel is small, the film stays taut and doesn't sag anywhere: the vacuum remains empty. But once you stretch the bagel to a certain size, a dent spontaneously appears in the film — the field starts to be felt at every point. This dent is not random.

A superfluid gas behaves like a frictionless liquid. Two clouds of such gas are connected by a narrow bridge, and a stream of particles flows through it. This resembles the Josephson effect in superconductors, but here the particles are neutral atoms instead of electrons.

A superconductor is like a city where electric current flows without traffic lights or jams. But the crystal UTe2 has a quirk: its surface follows different rules than its interior. On the tellurium atoms sitting at the surface, electrons found a 'loophole'—states with energies that are forbidden inside the crystal.

A magnetar is a neutron star with a magnetic field hundreds of millions of times stronger than Earth's. If you brought an ordinary magnet near such a field, it would instantly lose its magnetism, and atoms would stretch into thin filaments.

The white dwarf WDJ165335.21-100116.33 is the cooled core of a star, about the size of Earth but with the mass of the Sun. On its surface, there is an unusual hot spot that appears and disappears. Astronomers long puzzled over why the star's brightness changes every 80 hours.

In laboratories where atoms are cooled to near absolute zero, even a tiny change in the magnetic field throws off all the settings. Conventional sensors, Hall plates or coils with ferrite cores, sit a few centimeters away from the vacuum chamber because they themselves create interference.

Light is a stream of photons, and ordinarily a photon has no magnetic moment: it doesn't deflect in a magnetic field like iron filings.

Diamonds sometimes have a defect: instead of two adjacent carbon atoms, there is one nitrogen atom and an empty spot. This defect acts like a tiny antenna that responds to magnetic fields. Scientists aimed a laser and microwaves at such a diamond, and the defect started spitting out electrons.

In the stream of charged particles that constantly blows from the Sun, radio bursts sometimes occur — short, powerful signals at frequencies you can pick up on an ordinary radio. Until now, it was unclear how exactly these signals are born in that stream.

Quantum memory is like a fragile snowflake: one wrong move and it melts. Scientists are hunting for materials where such a "snowflake" can be held without fear of it melting. In the new work, they studied a calcium tungstate crystal doped with erbium, a rare-earth metal. It turned out that erbium inside this crystal has a hidden property that helps hold onto information.

A laser beam hits a shiny crystal, and comes back different: slightly shifted in color, with a different polarization. In a magnetic field, this transformation of light becomes especially noticeable.

A magnetic field is invisible, but you can make it 'glow'. To do that, take a tiny diamond with defects — places where a carbon atom is replaced by nitrogen and a neighboring lattice site is vacant. These defects, like sensitive compass needles, respond to the slightest changes in the magnetic field and emit light of varying brightness.

Dark matter is invisible, but according to calculations, it holds galaxies together. Catching its particles is like hearing a whisper in a noisy room. You need a material that responds loudly and noticeably to the slightest nudge. Molecular magnets could be such a material — substances where each molecule acts as an independent tiny magnet.