Precision experiments at ultralow temperatures enabled by quantum technology and superconducting electronics

Ultralow temperatures are favorable conditions for the realization of quantum technology in general and for quantum sensors in particular. One type of such quantum sensors are cryogenic detectors for particles and radiation, which have begun to revolutionize experiments in many areas of physics. Here we will discuss a specific kind of cryogenic detector, namely a metallic magnetic calorimeter (MMC) consisting of an absorber suitable for the particles to be detected, in close thermal contact with a paramagnetic temperature sensor. Together the two are connected by a weak thermal link to a thermal bath. Their universal applicability for the detection of different particles and radiation as well as their high resolution, wide bandwidth, fast and linear response make them a popular choice in many different applications today. Here we will discuss their principle of operation and their impact on precision gamma spectroscopy and neutrino mass determination.