How many – Kelvin do you have to reach for electrons to stop?

Answer

Dear Johan,

Indeed, it is true that the standard story on the Kelvin temperature scale notes that at 0K, the atoms are stationary. Note that noble gases are monatomic gases: ie the gas particles consist of 1 atom. This means that there are no further “internal” parts as with a molecule (which makes the story a lot more complicated).

However, this is a classic Newtonian image. When one looks at the world quantum mechanically, not all movement will have come to a standstill even at 0K (including the electrons). There are so-called zero-point vibrations, which are a consequence of the Heisenberg uncertainty principle. Because within quantum mechanics energy is no longer a continuous thing but can only change with steps, this ensures that there is a difference between the classical energy and the quantum mechanical energy.

The statement “We cannot perceive something that is -K.” is not correct. The Kelvin scale is an absolute scale that has no negative values ​​in the context of temperature as you are looking at it here. Kelvin’s work was incomplete in that it did not explicitly account for relativistic and quantum mechanical effects. On the other hand, the 0K position was an extrapolation since 0K was not reached in his experiments. Even today, 0K has never been reached. However, one can get horribly close and temperatures as low as 0.00000000045 K when forming a Bose-Einstein condensate of Sodium (in 2003). At such low temperatures, quantum mechanical effects become very important and very strange things start to happen, but that is another story.