I take this course at university called Waves and Optics, and a few lectures ago our teacher talked about the Fluctuation Dissipation theorem but I didn't really understand it. The math behind it is a total mystery for me because I still don't understand Poisson brackets and Liouville equation, among other things. Anyway, I'm not interested in the math part just yet, for now I'd just like to know the physics of this theorem i.e. what kind of phenomenon it describes, why is it helpful/necessary/(elegant/beautiful?), how it roughly works etc.. I would like to get just a general understanding. Once I get that, the math will become obvious I think.


closed as too broad by ACuriousMind, Danu, BMS, Kyle Kanos, Brandon Enright Oct 30 '14 at 6:08

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ @SlySherZ I'm sorry about your bad experiences, but I think you're 1) commenting on the wrong site. This is not a place to complain about your (bad) teachers 2) heavily over-generalizing. $\endgroup$ – Danu Oct 29 '14 at 22:45
  • 1
    $\begingroup$ It appears that the wikipedia article has a good intuitive and physical explanation (that does not involve any serious mathematics) under the header 'general applicability'. Did you read it? What exactly is it that you don't understand? $\endgroup$ – Danu Oct 29 '14 at 22:48
  • $\begingroup$ Ok i'll make my query more specific $\endgroup$ – David Hoffman Oct 30 '14 at 7:30