First we use superfluids to chill superconductors. We get these superconductors very cold – about a hundredth of a degree Celsius above absolute zero: the theoretically lowest temperature allowed by the laws of physics.

Superconductors are materials that conduct electricity with no resistance. This means that, unlike the more familiar conductors such as copper or steel, a superconductor can carry a current indefinitely without losing any energy.

Essentially, this is a superconducting qubit. By firing photons at the qubit, we can control its behavior and get it to hold, change, and read out information. Quantum control is concerned with how the classical world interacts with quantum devices.