quantum chip

A plastic film as thin as a hair, and inside it — platinum dots smaller than a millionth of a millimeter. These dots sit at the boundary between two transistor layers and catch electric charge like a sponge catches water. As charge accumulates, the transistor changes its resistance, and remembers that state.

In the world of quantum particles, there are introverts — anyons. They are unlike familiar electrons or protons. If you swap two such introverts, they remember the maneuver, as if leaving an invisible trace.

A sugar cube squeezed between your fingers will almost certainly crumble rather than compress evenly. A similar challenge faces quantum computer builders. They need to slightly stretch or compress miniature silicon plates — qubits are later placed on them.

Quantum networks need a mediator between storage — spin — and carrier — light. No single molecule had ever pulled off such a feat. But now physicists have found a solution. They placed a carbene molecule into a crystal and cooled it to -269°C.

The rows of wires stretching from the warm room into the fridge holding the quantum chip look like a tangled telephone exchange from the last century. Each qubit needed its own analog channel for precise tuning, and the cables carried extra heat and got underfoot. Now researchers have placed a digital-to-analog converter right in the cold zone, next to the qubits.

An ordinary laser emits narrow lines, like a string that sounds only one note. For spectroscopy, this is inconvenient: if a substance absorbs light between the lines, you might miss it.

An ordinary flash drive in your pocket gets warm even when it's just sitting there. Now imagine memory that, in the cold, uses almost nothing, like a thermos that never cools down. A superconductor carries current without loss at liquid-helium temperatures, but it couldn't store data. The new cell changes that.

A quantum computer is like an orchestra where every musician must play their part perfectly, or the melody falls apart. Previously, controlling qubits — the quantum 'musicians'—required a room full of equipment, and every extra wire added noise.

A quantum computer is like an orchestra where each musician plays their part, but if the conductor waves the baton a bit too hard, the delicate instruments go out of tune from excess heat. Controlling qubits at 10 mK (300 times colder than your freezer) is like conducting an orchestra in an ice-cold hall where even a breath can ruin everything.

An ordinary kitchen thermometer shows the temperature at which mercury stops resisting electricity. For superconductors used in quantum computers, the critical temperature is like a quality passport: the higher, the better.

Ordinary soldering doesn't work for quantum circuits: when cooled to liquid helium temperatures, metal cracks, and the contacts themselves introduce noise. Engineers from the research group tried something different — a drop of gallium alloy that stays liquid at room temperature, like mercury in an old thermometer.

A quantum computer based on electron spins is like a row of tiny spinning tops. Each top spins either clockwise or counterclockwise: that's a qubit. To find out the result of a computation, you typically stop the top and see which way it fell. But if you have many tops, each one needs its own "eye"—an extra helper qubit.

Light enters a tiny cavity with mirrored walls and hits an erbium atom hidden in a crystal. The atom absorbs the light and flips its nucleus into another state, like a toggle switch that clicks when pressed. But this switch is not ordinary: it obeys the laws of the quantum world and can be in two positions at once.

Two-dimensional bismuth on a silicon substrate is a promising material for future electronics. Its edges conduct current without loss, like a highway with no traffic lights. But bismuth itself is delicate: air and moisture quickly degrade its properties.

Quantum computers promise to solve problems beyond the reach of classical machines, but their heart, the qubits, requires ultra-low temperatures near absolute zero. Controlling qubits and reading out their states typically means working from a warm room, running many cables through the refrigerator.

Quantum technologies often use light, but not just as a light bulb — rather as a carrier of information. One approach is to encode data in frequency: each 'color' of a photon can be a separate memory cell. The problem is that working with such color states requires a whole lab: a photon source, filters, modulators, detectors.

A thin nanowire of α-Bi₄Br₄ — a compound of bismuth and bromine — conducts current not like an ordinary wire. Inside, electricity moves only along the edges, like water in a trough, not touching the bottom or sides. This behavior is called topological insulation: the interior does not conduct, but electrons glide losslessly along the surface or edges.

On a silicon chip that resembles a neighborhood, qubits, electrons with spin, live in separate 'houses.' Previously, neighbors could only chat over the fence, but now a road has been laid between them: along it, a qubit can ride to any of the four stops. The road is a bus that carries the electron without losing its quantum state.

A quantum computer is like an orchestra that has to tune its instruments before every piece. Tuning takes time and requires quiet — in our case, deep cold. For silicon chips with boron atoms, this tuning is usually done with microwaves, slowly and only at temperatures below 2 kelvin (minus 271 degrees Celsius).

A drop of ink falls into a glass of water, and instead of a flat stain, a ring is born that immediately starts to spin. That's roughly what the birth of a skyrmion looks like: light emitted by a tiny source twists into a stable vortex. Until now, such vortices could only be produced by large lasers.

A conventional computer sees the world flat: numbers are just points on a line. But a color image or a 3D scene demands more — four numbers that describe both position and rotation. Such quadruples are called quaternions, and until now electronics handled them clumsily, breaking them apart and reassembling them. The new chip changes the approach.

A massive refrigerator the size of a wardrobe hums, maintaining an interior colder than outer space. At its heart lies a silicon chip with tiny superconducting loops — qubits. But to make the chip work, dozens of thick copper cables snake from room temperature down to it.