I updated the value of the constant to take into account new SI definitions. The kilogram is now defined in terms of $h$, hence $h$’s value is fixed exactly.

]]>Names for $\hbar$

]]>added a brief *History*-comment just so as to link back to entries such a *black body radiation* and *ultraviolet catastrophe*

Thanks, Todd.

I have moved your addition up to the top. Then I added an Idea-section which points to the various subsections.

Will have to create an entry *physical unit* now.

Mentioning the Planck scale there would give a peg to hang on a funny observation of John L. Bell in some version of ch.1. of his primer of infinitesimal analysis, namely that the infinitesimal neighborhood of 0 is akin to the Planck scale in that there the order-theoretic structure of the smooth line breaks down. I wonder whether more could be made of this observation. Unfortunately, I can’t give a more precise reference here, because I have this version in electronic form only, and it isn’t contained in the first print edition nor can I find a corresponding text on his homepage.

]]>Well, I had the time and energy (measured in joule-seconds?) to put in a little something about Planck’s constant as a physical constant, but it might be considered embarrassingly low-level. In which case, please feel free to jazz it up to suit taste.

]]>It’s not too low level, no. Please add it if you have energy.

]]>Am a little surprised that nothing (or barely anything) was said about the dimension of $h$ as a physical unit, as measured in $(kg)m^2 s^{-1}$ or whatever. Is that considered too low-level?

]]>Added *Planck constant – Basic definition*, just for fun. (And also since it’s a point rarely made explicit, simple as it is.)

started an entry *Planck’s constant* with a remark on its meaning from the point of view of geometric quantization (and nothing else, so far).