I need intuition for Lagrangians and action

AI Thread Summary
Lagrangians and action are fundamental concepts in physics, serving as powerful calculational tools in both classical mechanics and quantum field theory. They are based on a variational principle, which suggests that nature follows the shortest path. Understanding these concepts requires engaging with quality resources, such as Landau & Lifshitz's classical mechanics. Additionally, Lagrangians are effective for deriving differential equations, highlighting their versatility. Gaining intuition about these topics is essential for deeper comprehension in advanced physics.
hideelo
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The title sort of 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.
 
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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.
 
dextercioby said:
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.
hideelo said:
The title sort of 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.
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.
 
dextercioby said:
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.
I'll check it out
 

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