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. A new circuit based on adiabatic quantum-flux parametron logic quantum-like models solves this problem: it generates microwave pulses to control qubits, using only 111 picowatts per qubit. For comparison, a fridge light bulb consumes billions of times more.
The secret to the savings lies in combining two signal transmission methods: microwave and time-division multiplexing. Previously, each qubit required its own wire running from the warm room into the cryostat, like a separate hose to each plant in a greenhouse. Now, multiple qubits can be controlled through just a few lines, as if a single pipe with valves sequentially delivered water to different beds. Meanwhile, virtual Z-gates are applied in parallel with X-gates, allowing any single-qubit operation without interrupting the flow.
The experiment confirmed that qubits controlled by the new controller maintain coherence: that is, they don't lose their quantum properties due to noise or heat. It's as if the orchestra played a most complex symphony in an ice-cold hall, and not a single string snapped from the cold, nor did the conductor break a sweat. Now we can scale up the number of qubits without worrying about the system overheating and going out of tune.
A temperature of 10 mK is 30 times colder than the cosmic microwave background radiation (about 2.7 K). At such cold, even thermal vibrations of atoms nearly come to a standstill.
In Hannu Rajaniemi's novel 'The Quantum Thief,' a world is described where computation happens at ultra-low temperatures and control requires minimal energy expenditure, just like in this development.