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.
Scientists took two nearly identical processors with different types of qubit contacts (Josephson junctions). One was made using the "bridge" method, the other using the "shadow" method (Dolan junctions). Both were cooled to ultra-low temperatures in two different refrigerators, and the researchers watched how often and how long the glitches lasted. It turned out that the error bursts closely resemble those caused by cosmic rays: they arrive randomly but with a certain frequency.
Why is that? The likely culprit is quasiparticles—"extra" electrons that get stuck in the superconductor and mess up the qubits. When the scientists sent control pulses (π-pulses) more often, the qubits returned to normal faster: the pulses seemed to pump out the extra particles. This is like shaking a rug to knock out the dust.
Now engineers know that the type of contact in a qubit affects not only accuracy but also how the chip copes with radiation. Perhaps in the future, quantum computers will be "warmed up" or "shaken" before important calculations to get rid of accumulated interference.
A single cosmic ray can temporarily spoil several neighboring qubits at once, like all the violins in an orchestra playing out of tune simultaneously.
In the series "Devs," a quantum computer glitches due to mysterious interference — here, there's a similar battle with invisible particles, but it's real.