# Start a new discussion

## Not signed in

Want to take part in these discussions? Sign in if you have an account, or apply for one below

## Site Tag Cloud

Vanilla 1.1.10 is a product of Lussumo. More Information: Documentation, Community Support.

• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeJul 5th 2012

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).

• CommentRowNumber2.
• CommentAuthorUrs
• CommentTimeMar 29th 2014

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

• CommentRowNumber3.
• CommentAuthorTodd_Trimble
• CommentTimeMar 29th 2014
• (edited Mar 30th 2014)

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?

• CommentRowNumber4.
• CommentAuthorUrs
• CommentTimeMar 30th 2014

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

• CommentRowNumber5.
• CommentAuthorTodd_Trimble
• CommentTimeApr 1st 2014

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.

• CommentRowNumber6.
• CommentAuthorThomas Holder
• CommentTimeApr 1st 2014

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.

• CommentRowNumber7.
• CommentAuthorUrs
• CommentTimeApr 1st 2014

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.

• CommentRowNumber8.
• CommentAuthorUrs
• CommentTimeJan 26th 2019
• (edited Jan 26th 2019)

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