New forms of matter near absolute zero temperature

First, I want to make some remarks about my career. In 1990, I made a major change in my life. I went from my native Germany to the US. I changed my research field from hot flames to ultracold atoms. And I went from applied physics to fundamental physics. I had enjoyed applied research in Germany. In combustion diagnostics, it is easy to explain what motivates you (clean environment, efficient combustion) and you receive a lot of acknowledgement from your family and friends. However, I realized that my talents were better matched to fundamental questions, where goals are sometimes fuzzy, research is exploratory, and real applications are decades away. It is much harder for me to explain now why a little puff of gas fascinates me, a tiny amount of matter, almost nothing, suspended in a stainless steel vacuum chamber. But I know that my current work is even more relevant in the long run than what I did earlier. In the US, at the Massachusetts Institute of Technology, I experienced an American elite university. As an assistant professor, I enjoyed the independence at an early stage of my career. In contrast to the “Juniorprofessur” in Germany, these positions are tenure track. This means that if the candidate is successful, he or she will be promoted to a permanent position at the same institution. I think it is important that young researchers know when they accept a junior position, that the number of permanent positions is matched to the number of people hired on junior positions. Young researchers are usually highly motivated and accept major sacrifices for their passion. They don’t expect to be hired immediately on a permanent faculty position, but they deserve to know that if they are successful, their academic career will continue. This perspective is provided by the tenure track system, but not by the old German system of “Habilitation” or by the new system of “Juniorprofessur”. In the scientific part of my talk, I explained how we reach extremely low temperatures below one nanokelvin, less than a billionth degree above absolute zero temperature. Atoms and molecules at room temperature zip around at the speed of jet airplanes (300 m/s), whereas at one nanokelvin, their velocity is less than 1 mm/s. However, the special and remarkable fact is that at such low temperatures, the atoms stop moving randomly, but rather march in lockstep. This is the phase transition called Bose-Einstein condensation, which was predicted in 1925 but observed only 70 years later. This discovery of a new form of matter has led to a flurry of worldwide activities and was recognized with the Nobel Prize in 2001.