Quantum computers store data in qubits – like a switch that can be on and off at the same time. This quantum ambiguity is extremely fragile: any noise destroys it in a split second – that's decoherence.

A new qubit, built from layers of a superconductor and the recently discovered altermagnet, works differently. Inside the altermagnet, electrons move like two opposing streams of cars on parallel lanes, never colliding. When current flows through this “sandwich,” interference occurs – waves overlap in such a way that noise cancels itself out. The qubit latches into one of two stable positions, like a door with a magnetic lock: random jolts won't open it.

But a precise electric voltage acts as an exact key: flips the qubit from “0” to “1” without bulky magnetic coils. This idea was proposed even earlier by Alexei Kitaev. Computer simulations show: the state is stored for tens of milliseconds – an eternity in the quantum world. Altermagnets are the third fundamental type of magnet, predicted only in 2019; they pave the way for precise quantum measurements and ultrasensitive quantum sensors.