I worked on a team (at a Company) that built a Scanning SQUID Microscope (SSM) to image magnetic flux trapping in superconducting circuits. The organization th

I worked on a team (at a Company) that built a Scanning SQUID Microscope (SSM) to image magnetic flux trapping in superconducting circuits. The organization that bought the SSM is working on these kinds superconducting microprocessors. A SSM uses a SQUID (superconducting quantum inference device) as an extremely sensitive magnetic flux sensor; SQUID sensor requires further amplification which is also typically a SQUID-based low-noise amplifier (long story). Same Company (I worked for) built cryostats for quantum computing research and all kinds of other cryogenic needs. There are a lot of issues with designing, fabricating, operating these sort of circuits at large scale... hence the need for a microscope to study flux trapping and other phenomena of operating circuits. But, overall, I'm optimistic that this technology can work. A note about energy consumption of this technology. Niobium thin film superconducting circuits have to be cooled to about 4 Kelvin to be 'properly 'operational'. Heat leaks from higher temperature stages into the 4 Kelvin cooling zone via conduction of thermal insulating supports, electrical signal lines, and thermal blackbody radiation. Several kW of power are required to provide 1 Watt of cooling power at 4 Kelvin. There are also small resistive/impedance losses in electrical signal lines connecting room temperature electronics to the superconducting chip. So... I think calling the microprocessor 'adiabatic' is a little disingenuous. Small amounts of power, in the form of many nano-amp and micro-amp currents are required to operate and interface with the chip... the chip cannot operate without this electrical interface. In additional, in a test environment where researchers are only running one chip... the overall cryogenic system, electronics, and superconducting chip are wildly energy inefficient compared to current microprocessors. But the "forward looking statement" is that hundreds of microprocessors could be run in one cryostat and the 5kW cooling budget would replace the power draw of 100's of classical microprocessors while also provide higher equivalent FLOPS per process processor. But this "forward looking statement" is NOT true today, as far as I am aware.