Undergrad Fermat's principle of least time

[LLT71]

while I was studying "fermat's principle of least time" I was (and still I am) ntrigued by the fact that "out of all possible paths that it might take to get from one point to another, light takes the path which requires the shortest time". this question may be a bit philosophical but: "how" light "knows" and "chooses" (out of all possibilities) the path which requires the shortest time? these days I am also into generic algorithms so I got this silly thought running through my head: what if light is like some kind of super computer which operates with constant CPU speed 300[km/s] and has some generic alghorithm for choosing the best path!?
thanks!

 

[Nugatory]

"how" light "knows" and "chooses" (out of all possibilities) the path which requires the shortest time?

Take a look at the "Derivation" section of the wikipedia article on Fermat's principle: https://en.wikipedia.org/wiki/Fermat's_principle#Derivation

Fermat's principle follows directly from the fact that light is electromagnetic waves. There's also an explanation based on the theory of quantum electrodynamics; Feynman's "QED: The strange theory of light and matter" includes an excellent and layman-friendly explanation of how this works.

 

[LLT71]

Take a look at the "Derivation" section of the wikipedia article on Fermat's principle: https://en.wikipedia.org/wiki/Fermat's_principle#Derivation

Fermat's principle follows directly from the fact that light is electromagnetic waves. There's also an explanation based on the theory of quantum electrodynamics; Feynman's "QED: The strange theory of light and matter" includes an excellent and layman-friendly explanation of how this works.

thank you!

 

[robphy]

Following up on @Nugatory 's suggestion:
here are videos associated with QED book

(see 64m00s)


(see 17m59s)


see http://www.feynmanlectures.caltech.edu/I_26.html (the bottom diagram on that page is developed in the second video above at 34m30s )

 

[LLT71]

Following up on @Nugatory 's suggestion:
here are videos associated with QED book

oh, wow! many thanks my friend!