Method for Cooling Nanostructures to Microkelvin Temperatures

We propose a new scheme aimed at cooling nanostructures to microkelvin temperature based on thewell established technique of adiabatic nuclear demagnetization: we attach each devicemeasurement lead to an individual nuclear refrigerator, allowing efficient thermal contact to amicrokelvin bath. On a prototype consisting of a parallel network of nuclear refrigerators,temperatures of 1 mK simultaneously on ten measurement leads have been reached upondemagnetization, thus completing the first steps toward ultracold nanostructures.