error rate

In 1996, physicists asked: how much noise can a quantum channel withstand before it stops transmitting information? A phone call where every third word is replaced by random noise is still understandable. Up to what level of interference can the listener still grasp the meaning?

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.

A hunter sets snares in the woods. They know the animal's habits but not whether it will ever show up. In much the same way, physicists set up detectors in hopes of catching particles of dark matter — the invisible substance thought to make up most of the Universe's mass. A new study offers hunters an unusual tool: not a trap, but a measuring tape.

The quantum world is full of strange connections. Two particles can become “entangled”: the state of one instantly affects the other, even if they are kilometers apart. But how do you know if they are truly entangled? It's like a ball of yarn: at first glance, you can't tell whether it's a single tangled ball or just a mess of loose threads.

If you accelerate an observer to near-light speed, the emptiness around them stops being cold. A thermal glow emerges — an effect predicted in 1976 and named after William Unruh. For earthly accelerations, this glow is vanishingly faint, like a whisper at a rock concert.

Imagine a smart antenna panel, a phased array, that steers radio waves traveling at the speed of light. It works like an orchestra: hundreds of tiny emitters, like musical instruments, shift their phase (the moment they 'join' the overall sound) on command via a variable voltage.

Conventional antennas for precise direction finding must work coherently: they capture not just volume, but also the wave's phase at a given moment. The slightest tuning mismatch, and the direction is lost. The new method relies solely on signal strength. It's like finding your way in fog, seeing only the brightness of lights, not their color.

Code-writing assistants often behave like a chef who, to boil a single egg, rereads the whole cookbook. When asked to make a tiny fix, they reopen dozens of files and retrace long-familiar connections. This is unnecessary work — energy going to waste.

Quantum computing suffers from 'false notes' — errors that arise from the slightest inaccuracy. Now they are eliminated with the precision of tuning a concert grand piano. The idea traces back to the dreams of pioneers — David Deutsch and Peter Shor — of flawless operations.

Picking out a single faulty microchip from a million, without any clue what the fault looks like, is a classic needle-in-a-haystack problem. A classical computer would test each chip one by one.

A candle flame in a draft dances: now it flares up, now it almost goes out. Quasars behave much the same way — supermassive black holes in the centers of distant galaxies, surrounded by a scorching disk of infalling matter. Only they flicker not over seconds, but over months and years.

A quantum computer measures a molecule's energy much like an old tape measure that only has markings every meter. If the actual length of a table is 2.37 meters, the tape shows “two and a bit,” and you can't do better. Physicists call this resolution: the step of the grid, finer than which you cannot go. The authors of the new work turn this flaw into an advantage.

Quantum calculations are a recipe with perfect ingredients, but nature-the-chef cooks in her own way. Machine-learned models of atoms memorize the recipe and predict material properties in seconds instead of weeks.

A quantum computer is like an orchestra where every musician must come in at exactly the right moment. Previously, to play a complex piece, you had to constantly move the instruments around — slow and noisy. The new scheme, called "parity architecture," keeps everyone in place, and the conductor simply changes the notes.

A neutral-atom quantum computer is like a library where books not only need to be read but also quickly returned to the shelf. Slow readout of results is like a sluggish librarian holding up the entire queue. Scientists have found a way to speed up this process by adding helpers.

A laser that usually produces a steady beam starts to tremble near its threshold, like a string about to sound. This trembling is not a defect but quantum noise: atoms inside the laser emit light randomly, without any external cause.

Quantum computers promise to solve problems that are beyond the reach of ordinary computers. But their components, quantum bits, are very sensitive. One type of quantum bit is an oscillating circuit that can exist in two states, like a pendulum swinging left or right. These states store information.

Instead of millions of rigidly fixed particles — 10,000 atoms, working as beads on a quantum abacus. Each bead can be both zero and one at the same time. But the key is: if an error creeps into the calculation, the atoms can be physically moved: as if you could rearrange the abacus on the fly so that the glitch doesn't ruin the result.

Galileo, legend has it, dropped balls from the Tower of Pisa to prove that heavy and light objects fall equally. This law formed the foundation of Einstein's theory of gravity. Today, scientists have turned an entire space station into such a tower.

A coin toss seems random, but in reality, physics decides everything: the force of the throw, air resistance, the surface's elasticity. If you knew all the details, you could predict the outcome. True randomness lives deeper — in the quantum world.

Like an iceberg, the visible part of the code is the data, while beneath the surface lies a massive foundation of auxiliary particles. They quietly monitor noise and fix errors without touching the information. This approach squeezes many protected logical qubits into a modest number of physical ones. The experiment ran on a 98-ion processor inside an electric trap.

A quantum computer is like an orchestra where each musician, a qubit, must play its note without missing a beat. But every now and then, a passerby, a particle of radiation from space, bursts into the hall and throws the musicians off rhythm. Such glitches are called error bursts, and they disrupt computations.

Ultra-precise scales that catch the slightest changes in gravity work like a keen ear: they hear even the whisper of distant underground voids or the tremors of the Earth's crust. But such instruments have a hidden enemy: their own internal clocks. Time inside the sensor also jitters, and this jitter smears the picture.

A tossed coin is the simplest source of randomness. But if the coin is shaved, it starts cheating. In the quantum world, light plays the role of the coin: its properties are fundamentally unpredictable. The catch is that the device that “flips” the quantum coin might be faulty or even swapped by an adversary.

Optical fiber transmits light, but along the way it jitters and dims. To ensure that two parties at opposite ends of the line get the same set of random numbers for encryption, the receiver uses a digital corrector, like noise-canceling headphones that subtract the street hum but sometimes also eat the quiet notes of the music.

A quantum computer is like an orchestra where each qubit is a musician, and a measurement is the conductor's attempt to hear who played what. But the hall is noisy: the signal fades like sound through a thick wall, and the conductor himself sometimes mixes up the notes.

A quantum bit, or qubit, is like a coin spinning on a table, able to be both heads and tails at once. For the computer to know what came up, you have to stop the coin and look. Previously, this stopping was done with a delay: data was read out, taken to a regular computer for processing, and only then was the result known.

Quantum computers use GKP states, dreamed up by Alexei Kitaev, John Preskill, and Daniel Gottesman. Their hallmark is built-in stabilizer checks that catch errors. For a long time, it was believed that a successful check guaranteed a nearly perfect state. Alas, it's an illusion.

All bodies fall the same: this was first observed by Galileo. Einstein elevated the observation to the equivalence principle: gravity and acceleration are indistinguishable, giving birth to curved spacetime.

Turning CO₂ into fuel is like finding the one perfect way to pack billions of items into a suitcase. A classical computer tries options one after another, taking decades, while a quantum computer sees all combinations at once.

Picture an orchestra of 120 musicians playing in perfect unison — one false note and the harmony crumbles. That's the metaphor for a record-breaking quantum ensemble. Physicists have for the first time entangled 120 superconducting qubits, the building blocks of future computers.

Two superconducting qubits on a single chip sound as clean as soloists in an orchestra. Each is a transmon, a qubit with reduced sensitivity to charge noise. They are connected through a tunable coupler, an auxiliary element that adjusts the interaction strength between them.

A quantum computer is like an orchestra: each musician plays their part, but the slightest false note ruins the symphony. The physical qubits it is built from are noisy and error-prone. To protect computations, they are combined into logical qubits using quantum error correction.

In a dark room, a resonator catches light the way a spiderweb catches dew drops. A laser pulse bursts in, and the mechanical membrane starts to vibrate in sync, leaving a trace in the very fabric of the system. That is how memory is born: not in a silicon cell, but in the dance of photons and phonons.