fq gravity

An ordinary mirror swaps left and right. Many laws of physics don't notice the swap: they are mirror-symmetric. But some phenomena, like the weak interaction, break this symmetry. Until now, it was thought that gravity and light each break mirror symmetry in their own independent way.

Stare long enough into the night sky, and sooner or later your gaze hits a blackness beyond which nothing is visible. This is not just a distant fence: it is the edge of the universe accessible to us, the cosmic horizon. Light from more distant stars simply hasn't had time to reach us.

A black hole is not just a dark spot in space. It has a temperature, and it radiates. It has entropy — a measure of hidden information encoded on its horizon's surface, like a pattern on a soap bubble.

In the first instants after the Big Bang, the universe expanded faster than light could cross it. Like an inflating balloon, but instead of rubber, it was space itself. On this balloon, ripples inevitably formed — tiny compressions and rarefactions from which all galaxies and stars later grew.

Quantum field theory is the language physicists use to describe elementary particles and their interactions. The authors of the work decided to slightly "tweak" this language: they introduced deformations, that is, small changes to the rules of the game.

Light escaping a massive body loses steam. Its frequency dips slightly, and its color shifts toward red. Physicists call this gravitational redshift. In classical theory, it's all clear, but the moment you bring quanta into the picture, trouble starts. Previously, this shift was modeled as a kind of mode mixer — a device that entangles different states of light.

A quantum computer is usually like an assembly line: operations proceed one after another, and each error accumulates. In the new work, physicists tried a different path — an architecture where the computation grows out of the measurement process itself. They took 56 ions in a trap and wove them into a three-dimensional cloud of entangled particles.

A pendulum in a noisy room is constantly jostled by people passing by. Its motion is a mix of regular swings and random jerks. Something similar happens with weak gravitational waves against the backdrop of an expanding universe. In Einstein's general relativity, these waves are tiny ripples in spacetime.

In the quiet of the quantum world, there is no emptiness. Particles are intertwined by invisible threads — entanglement. The authors of the work proposed that the very fabric of spacetime is woven from these threads. This is not just a metaphor: they built a mathematical framework where the distance between points is determined by how much shared information they hold.

An optical trap holds an atom almost motionless, like a ball on a soft spring. But as soon as acceleration appears, say gravity, the equilibrium shifts. The atom moves within the standing light wave, and this changes the rate at which it exchanges energy with the field. The frequency of this exchange becomes a direct indicator of acceleration.

A quantum particle can be a wave, and pass through two paths at once. But if something 'peeks' at which path it took, the wave disappears. This effect is called loss of interference. Usually, photons or air molecules do the peeking.

A light ray skimming along a black hole horizon doesn't just move: it carries heat and information. Physicists have long suspected that the geometry of such rays obeys strict rules, but the details remained blurry. The new work turns these rules into a sharp inequality.

In the first moments after its birth, the universe expanded faster than a match lights. This process is called inflation. It explains why today's cosmos is so homogeneous and flat. But what happened before it? Perhaps the laws of quantum gravity were at work then, and their traces can be found in the data.

A thousand years ago, Vikings took Iceland spar to sea. The translucent crystal split light into two rays. By their brightness, they could find the sun even in fog. Birefringence — the physical term for this phenomenon — now helps hunt for the most elusive force in the cosmos.

A black hole's horizon is not a wall but rather a one-way membrane. Anything that crosses it disappears forever. Stephen Hawking showed that this boundary should glow faintly, emitting particles. But catching such radiation from a real black hole is impossible: it's too far and too dim. Physicists have found a workaround: build a "toy" black hole out of magnetic atoms.

A potter tries to measure the thickness of a jug's wall, but every time the gauge also reports the curvature of the vessel.

When two black holes merge far away, we receive a tremor of space — gravitational waves. Usually, they are described by Einstein's equations, but what if gravity works differently at the tiniest distances? The authors took one such hypothesis — Hořava–Lifshitz gravity.

Gravity isn't just the force that keeps us on the floor. On cosmic scales, it conducts galaxies, bends light rays, and decides the fate of everything. A century ago, Einstein described it as the curvature of space and time.

In 1915, Albert Einstein and Wander Johannes de Haas demonstrated that when an iron rod is magnetized, it twists slightly — the angular momentum of electrons is transferred to the crystal lattice.

Two synchronized swimmers dive into the sea. One hits calm water, the other a whirlpool. Their movements, perfectly coordinated at the start, diverge. Something similar happens to two quantum particles when one moves in flat space and the other in curved space.

An endless ocean where every wave carries information about what happens in the depths. That is roughly how our Universe works under the holographic principle: the physics inside a volume can be described by processes on its boundary.

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.

A quantum wave is like a long-exposure photograph: everything’s blurred, but the blur itself reveals motion. Usually these frozen waves are treated as convenient abstractions. Yet if at each point in the image you estimate, by brightness, the moment on the particle’s internal clock it landed there, flat space suddenly acquires curves.

A translator who translates not words but the very structure of a conversation runs into trouble when the chat moves beyond a quiet room. In a familiar simulation on a spatial lattice, everything follows a strict script. But the moment the interlocutors find themselves in a noisy square, where sound is distorted by echoes and the crowd keeps changing direction, the script falls apart.

Building a house on sand is a bad idea. In physics, it was long believed that a quantum theory of gravity could not be built on a fixed "sand"—a pre-existing spacetime.

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.

The void is never truly empty. In curved spacetime (for instance, in an expanding universe or near a black hole) the vacuum heats up. This is reminiscent of how acceleration makes particles appear seemingly out of nowhere: a phenomenon known as thermal vacuum radiation.

Why do some systems, from gene networks to air travel, preserve imprints of the past longer than others? For a long time, network science blamed topology: the number of connections, modularity, spectrum. But two networks with the same skeleton can remember and forget in completely different ways.

The Universe has a rate at which it expands — called the Hubble constant. The problem is that the two most precise ways to measure it give different numbers. One method, using the early light of the Universe (the cosmic microwave background), gives one value.

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?

Gravity is usually explained through the curvature of spacetime. Massive bodies press it down like a bowling ball on a stretched rubber sheet. But this approach has two lesser-known twins. In one, gravity arises from torsion (twisting) of spacetime; in the other, from its non-metricity (when lengths and angles change during transport).

In 2015, detectors caught a gravitational wave for the first time — a ripple in space that traveled from merging black holes. Since then, such signals have become a new window into the universe for astrophysics. But gravitational waves can do more: they carry the imprint of the very theory of gravity.

A single particle can be in two places at once — that's superposition. But any interaction, like a shout, instantly 'collapses' this uncertainty. It was long thought that even gravity could interfere.

A taut sheet wrinkles. If you tug a corner, a smooth wave runs across; if you sharply bunch the fabric, a sharp crease forms. Space and time in Einstein's equations behave much the same way. Gravitational waves resemble the gentle ripples of the sheet, while shock fronts are like stiff folds where matter's properties change abruptly.

A levitating dust grain in an optical trap is an ideal pendulum for measuring gravity. It hangs in vacuum, never touching the walls, and its motion depends only on external forces. The new work proposes an improved sensor: a mechanical 'squeezed' qubit based on a nonlinear oscillator.

Some solutions to Einstein's equations allow closed timelike curves — loops that let you travel to the past. Two well-known designs, the Ori geometry and the Ahmed geometry, do without exotic matter, catching physicists' eyes.

The quantum world is known for uncertainties: for example, you can't measure a particle's position and its speed at the same time. But new research shows that in a 'fuzzy' spacetime, even probability itself — the measure of chance — loses sharpness. A foggy compass doesn't give an exact direction: its needle wavers.

Gravity isn’t fundamental: it’s a shadow cast by entropy, the measure of disorder. Back in the 1970s, Jacob Bekenstein and Stephen Hawking found that black holes store disorder on their surface, as if information is smeared across the shell.

A stone drops into a pond, and ripples spread across the water. If a protruding branch blocks the ripples' path, part of the wave reflects, and part bends around the obstacle. Gravitational waves, ripples in spacetime itself, behave similarly when passing by galaxy clusters or black holes.

A heavy ball rests on a trampoline, and the fabric sags beneath it. Any rolling ball nearby inevitably rolls toward the center. This is roughly how gravity works on the scale of the entire Universe. But what if the fabric were arched upward, like a dome? Then the ball would tend to roll outward.