Quantum chip survives a year of reboots express
A quantum computer is like an orchestra where every musician must play with precision down to a billionth of a second. If one instrument goes out of tune, the whole symphony collapses. So scientists spent a year watching 27 qubits — the simplest cells of quantum memory. Four times, they powered the system down, warmed it to room temperature, and then froze it again to near absolute zero.
The qubits themselves withstood this jolt surprisingly well. Their main frequency, the one they 'sing' at, shifted by less than half a percent. The time a qubit can hold information also didn't degrade. But the qubits' environment changed beyond recognition each time. Tiny defects in the material, called two-level systems, that cause noise were reshuffled after every cycle, like a deck of cards.
It's like a house that stands firm, but after each winter, new floorboards creak. The walls are intact, but you have to get used to the sounds all over again. For quantum computers, this means that after every power-up, each qubit must be automatically recalibrated. Without such adjustments, a large quantum computer simply cannot run stably.
Two-level defects are tiny patches of material that behave like miniature magnets, randomly flipping their orientation. They are the main source of noise in modern quantum chips.