Measuring the properties of superconducting materials in magnetic fields at close to absolute zero temperatures is difficult, but necessary to understand their quantum properties. How cold? Lower than 0.05 Kelvin (-272°C).
“For many modern (quantum) materials, to properly study the fine details of their quantum mechanical behavior you need to be cool. Cooler than was formerly thought possible,” said Ruslan Prozorov, a physicist at the U.S. Department of Energy’s Ames Laboratory, who specializes in developing instrumentation which measures just such things.