Zero kelvin is the lowest possible temperature. At absolute zero, all motion comes to a standstill. It is obvious that a lower temperature is not feasible because there is no velocity smaller than zero and no energy content less than nothing.
Auto emission is hazardous and has to be controlled.
Laser cooling opened a new route to ultralow temperature physics. Laser cooling experiments, with room temperature vacuum chambers and easy optical access, look very different from cryogenic cells with multi-layer thermal shielding around them.
Bose-Einstein condensation is one of the most intriguing phenomena predicted by quantum statistical mechanics.
My explorations of the technical world started with Legos, with which I was quite creative in constructing moving objects with the basic building blocks that were then available.
Running is a way for me to relax. With one hour of intense running, I can get a lot of physical exercise. I can relax my body. I feel a tension in my muscles when I don't run. In that sense, I need to get out a few times a week in order to do my work as a scientist, which involves a lot of sitting still.
I used the Nobel money to buy a house and for the education of my children.
When air is hot, the molecules move fast and they have high kinetic energy. The colder the molecules are, the smaller their velocities are and, subsequently, their energy. Temperature is simply a way to characterize the energy of a system.
Bose and Einstein had triggered low-temperature experiments that have led to the discovery of new matter. I owe my work and my Nobel to them.
When I was around thirty, I met my own personal challenge and finished a few marathons under three hours, and I have completed many long bicycle tours.
Explorations into chemistry were done in our basement, sometimes with friends, and my parents must have had quite a bit of confidence in my abilities when they allowed me to experiment with explosive mixtures.
After earning my Ph.D., I stayed at the Max-Planck Institute as a postdoc, working on laser excitation of Rydberg states of triatomic hydrogen and helium hydride. I also succeeded in analyzing all the emission spectra of helium hydride, which I had discovered during my Ph.D.
Imagine how many aspects of nature we would miss if we lived on the surface of the sun. Without inventing refrigerators, we would only know gaseous matter and never observe liquids or solids, and miss the beauty of snowflakes.
Amplifying atoms is more subtle than amplifying electromagnetic waves because atoms can only change their quantum state and cannot be created. Therefore, even if one could amplify gold atoms, one would not realize the dreams of medieval alchemy.
When I was running the marathons in Munich, I always trained by myself. Between the demands of graduate work and a young family, I had to train at unusual hours. A few times, I ran home from my lab late at night, which was 20 kilometers out of town.
As a scientist, I play in the top league - the Olympics, the World Championships - and I want to be in the lead. As a runner, I set personal goals, and I want to push beyond my own personal limits. I was very happy when I practiced for several months and then reached my goal to run a marathon in 2:50.
I think both running and science reflect certain character traits. I have endurance, patience, and ambition. I'm willing to work hard toward a goal, to push myself and overcome limits. Running and science both let me express these traits.
Maybe if you win a Nobel Prize in economics, you make a lot of money by giving talks... but not in my area.
When I run, I think about everything: physics, family problems, plans for the weekend. I haven't made any big discoveries on a run, but it does give me time to think through problems. Some solutions are obvious, but they are only obvious when you are relaxed enough to find them.
To go below one nanokelvin is like running a mile below four minutes for the first time.
