Understanding the Concept of Canonical Transformation in Hamiltonian Mechanics

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Homework Help Overview

The discussion revolves around the concept of canonical transformations in Hamiltonian mechanics, specifically focusing on the independence of conjugate variables during transformations from (q,p) to (Q,P) while maintaining the Hamilton equations of motion.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are exploring the meaning of independence between the variables q and Q, questioning how Q can be independent of q if it is expressed as a function of q, p, and t. They are examining the implications of linear dependence in their time derivatives.

Discussion Status

The discussion is ongoing, with participants seeking clarification on the definitions and implications of independence in the context of canonical transformations. There are multiple interpretations being explored, particularly regarding the relationship between the time derivatives of the variables.

Contextual Notes

Participants are grappling with the definitions provided in their textbook, which may not fully clarify the concept of independence in the context of canonical transformations.

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There's a part in my book that I don't understand. I have attached the part and it is basically about how to transform from a set of conjugate variables (q,p) to another (Q,P) while preserving the hamilton equations of motion. I don't understand what he means by q,Q being separately independent. Don't we seek transformation where Q is a function of q. Maybe I'm just not into what he means by this independency.
 

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It's true, but he means that for F q and Q are variables, so that there's no linear dependence between their time derivatives. Such a linear dependence would spoil his argument.
 
Please elaborate. If Q = Q(q,p,t) how is its time derivative independent of q? :(
 
Well, what is said was that there is no linear dependence between [itex]\displaystyle{\dot{Q}}[/itex] and [itex]\displaystyle{\dot{q}}[/itex].
 
but dQ/dt = [itex]\partial[/itex]Q/[itex]\partial[/itex]q dq/dt + ...
How is that not a relation between them?
 

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