The scientific world has a simple rule: for accurate calculations, the computer must begin each calculation from scratch. This applies to any computing systems, but it is especially difficult to observe this requirement in quantum machines – their elements are too sensitive to heat and radiation, which is why it is difficult to preserve their initial parameters. A group of physicists from the Chalmers Technological University in Sweden found a solution to the problem . They developed a quantum refrigerator for computing systems working on superconducting elements. The device can cool them to a record low temperature – 22 million, which helps to maintain the original parameters before the start of the calculations.
Superfiguing schemes have become one of the main directions in the development of quantum computers. At extremely low temperatures, special energy levels appear in them, thanks to which information can be recorded in two different conditions: the base and excited. Like bits in a regular computer, each quantum element can be located either in one of these provisions or in their quantum superposition. This ability to enter the state of superposition allows the machine to simultaneously check many options for solving the problem, which gives a tremendous advantage over ordinary computers.
When starting, all quantum elements must remain in the base state, for which maximum cooling is required. However, even the best cryogenic installations cannot completely isolate the elements from external heat. Some of them accumulate enough energy to go into an excited state. This makes errors already at the beginning of work, which accumulate as the task is completed. As a result, you have to spend more resources on correcting errors.
The Gasparinetti team figured out how to solve this problem using a quantum cooler that takes excess heat using the temperature difference. Such a difference naturally occurs inside cryogenic installations for quantum computers. Cooling elements are arranged stepwise: each next level is colder than the previous one, and at the last level the temperature drops to about 10 millikelvins.