1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

I need intuition for Lagrangians and action

  1. Jul 15, 2015 #1
    The title sorta says it all, but I'll clarify a bit. Is there any intuition for what Lagrangians are and what action is. I'm asking in all generality, not just for classical mechanics.
  2. jcsd
  3. Jul 15, 2015 #2


    User Avatar
    Science Advisor
    Homework Helper

    In a nutshell, they are very handy calculational tools, especially when doing quantum field theory, one of the 2 most successful theories of physics. Intuition is built once you read the proper sources. I'd consider Landau&Lifshits' classical mechanics gem.
  4. Jul 17, 2015 #3
    Hi, I definitely subscribe this but I would like to add: Lagrangians are nothing else but the formulation and application of a variational principle. It works since nature seems to use the shortest path. It begins from classical mechanics of some particles, is great if you come then to field lagrangians and they are used in classical mechanics and QFT wildely.
    I just wanted to mention that they are superb tool to derive differential equations and I personally recommend "Boundary and Eigenvalue Problems in Mathematical Physics" by Sagan.
  5. Jul 17, 2015 #4
    I'll check it out
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook