Editorial

Can’t get any colder!

It was an extreme winter. In 1929, a cold spell that lasted for weeks turned rivers and lakes in Europe into ice. In February, the thermo­meter in Wolnzach in Upper Bavaria dropped to minus 37.8 degrees Celsius – a cold record for Germany, according to the German Weather Service. The record low temperature on Earth, measured in 2013 by a NASA satellite on a plateau in East Antarctica, is significantly colder, namely minus 93 degrees Celsius. This is so icy that it makes human life practically impossible. Yet, it is still far from absolute zero in terms of temperature: this is minus 273.15 degrees Celsius or 0 degrees Kelvin. At this temperature, even the atoms themselves stop moving. The comfortable temperature for many qubits, the computing units of quantum computers, is just above absolute zero. For these extreme conditions, Jülich researchers are developing so-called cryo-electronic technology that controls the qubits. Our cover story tells why and how they do this.