Keeping the Quantum Computers of the Future Cool

One of the biggest issues facing the development of quantum computers—tomorrow's supercomputers based on the strange principles of quantum physics—is keeping everything cool. Electronics make heat, and while your laptop and smartphone can use fans or heat-absorbing water tanks, those just won't cut it for quantum computing, which will take advantage of the quirks of quantum mechanics to create computers that calculate at insane speeds.

"When you start to make electronics smaller and denser, not only are you making much more heat in the same amount of volume, but it's much harder for the heat to flow outward," says Peter Nalbach, a theoretical physicist at the University of Hamburg, Germany.

At this stage, our early attempts at quantum computers have to be kept at a temperature barely hovering above the insanely cold, dead-standstill of absolute zero. If you're trying to develop a large-scale quantum computer, Nalbach, says, "at a certain point, you'll have to actively transport heat out of the spot where it's created," Until now, engineers had no idea exactly how to do this.

But Nalbach and his colleagues have just published the schematics of a method to individually target and cool the physical building blocks of tomorrow's quantum computers. In their outline, recently published in the physics journal Physical Review Letters, the physicists show how they can halve the temperature of individual quantum dots—nano-sized pieces of crystal that are currently being investigated as qubits for quantum computers.