Encyclopedia … combined with a great Buyer's Guide!

Sponsorship opportunity: support this popular resource, which serves the whole photonics community, and get recognition!

Heisenberg's Uncertainty Principle and the Transform Limit

Posted on 2008-06-13 as a part of the Photonics Spotlight (available as e-mail newsletter!)

Permanent link: https://www.rp-photonics.com/spotlight_2008_06_13.html

Author: , RP Photonics Consulting GmbH

Abstract: It is sometimes claimed that the transform limit for pulses is strongly related to Heisenbergs uncertainty limit. The article shows that this is nonsense; there is nothing more than a vague similarity. One should not confuse physics (statements on nature) with mathematics.

Dr. Rüdiger Paschotta

Ref.: encyclopedia articles on transform limit, bandwidth-limited pulses, time–bandwidth product, Spotlight article of 2007-10-11: "Understanding Fourier Spectra"

Optical pulses are subject to the well-known transform limit: for a given pulse duration, there is a minimum spectral bandwidth (width of the Fourier spectrum). This limit is sometimes connected with Heisenberg's uncertainty principle, saying (in one form) that the more well-defined the time of some process is, the bigger the uncertainty on the involved energy transfer.

This does sound somewhat similar, taking into account that energy is related to frequency in quantum mechanics, and Fourier transform pairs are involved in both cases. Nevertheless, it is nonsense to claim that the transform limit for pulses is strongly related to Heisenberg's uncertainty limit. After all, we are dealing with two very different issues:

In conclusion, there is a vague similarity, nothing more. The transform limit has essentially nothing to do with quantum mechanics (or quantum optics).

Another question would be whether it was a good idea to call Heisenberg's uncertainty principle a principle. But before making too many enemies, including famous (dead) physicists, I stop the discussion at this point!

This article is a posting of the Photonics Spotlight, authored by Dr. Rüdiger Paschotta. You may link to this page and cite it, because its location is permanent. See also the RP Photonics Encyclopedia.

Note that you can also receive the articles in the form of a newsletter or with an RSS feed.

How do you rate this article?

Click here to send us your feedback!

Your general impression: don't know poor satisfactory good excellent
Technical quality: don't know poor satisfactory good excellent
Usefulness: don't know poor satisfactory good excellent
Readability: don't know poor satisfactory good excellent

Found any errors? Suggestions for improvements? Do you know a better web page on this topic?

Spam protection: (enter the value of 5 + 8 in this field!)

If you want a response, you may leave your e-mail address in the comments field, or directly send an e-mail.

If you enter any personal data, this implies that you agree with storing it; we will use it only for the purpose of improving our website and possibly giving you a response; see also our declaration of data privacy.

If you like our website, you may also want to get our newsletters!

If you like this article, share it with your friends and colleagues, e.g. via social media: