A quantum computer is like an orchestra, where each qubit is a musician playing their part. But every now and then, a cosmic ray bursts into the hall, and the violinist flinches, losing the rhythm. These particles from deep space pierce the chip, knock out extra electrons, and spoil the delicate quantum music.
To tackle the interference, physicists built a special test rig. Inside, an electron accelerator fires single particles at a superconducting chip with several qubits. One such electron deposits as much energy in the chip as a typical muon from cosmic rays. The scientists watch the qubits make mistakes and learn to catch those errors.
It turned out that glitches depend on where exactly on the chip the superconducting contacts, Josephson junctions, are located. If a particle hits near them, the qubit loses its quantum state faster. Now engineers can position these elements so that cosmic rays interfere less.
A muon is a heavy cousin of the electron. It lives for just two millionths of a second, but in that time it can travel hundreds of meters and punch straight through even thick walls.
In the TV series "Devs," a quantum computer suffers from interference and glitches, just like real machines that are bothered by cosmic rays.