Canonical Transformation and harmonic-oscillator

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Homework Help Overview

The discussion revolves around a canonical transformation involving variables Q and P, defined in terms of p and q, and its application to the harmonic oscillator problem. Participants are exploring the properties of this transformation and the associated generating function.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss verifying the canonical nature of the transformation through Poisson brackets and express uncertainty about deriving the generating function. Questions arise regarding the relationship between the generating function and the Hamiltonian.

Discussion Status

The conversation is ongoing, with some participants confirming the canonical nature of the transformation while others seek clarity on the generating function and its connection to the Hamiltonian. Multiple interpretations of the generating function are being explored.

Contextual Notes

There is mention of specific equations and assumptions related to the harmonic oscillator, as well as a potential misunderstanding about the role of the Hamiltonian in the context of the transformation.

Shafikae
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Show that the transformation
Q = p + iaq , P = (p-iaq)/2ia
is canonical and find the generating function. Use the transformation to solve the harmonic-oscillator problem.

I was able to determine if the transformation is canonical, and it is. However, when it came to finding the generating function, I wasnt getting it right. And how do we use this transformation to solve the harmonic oscillator?
 
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Well, what do you know about generating functions?...What does the Hamiltonian become under this transformation?
 
I don't know how to obtain the Hamiltonian. But i know that to check whether the transformation is canonical, we can show that the Poisson brackets are invariant. Which I have shown they are. I'm not getting the right generating function, or is the generating function really the hamiltonian??
 
Shafikae said:
I'm not getting the right generating function, or is the generating function really the hamiltonian??

Well, what are you doing to obtain the (incorrect) generating function?

I don't know how to obtain the Hamiltonian.

You don't know what the Hamiltonian of the one-dimensional harmonic oscillator is?
 
Ok so I take the poisson bracket and obtain 1, therefore its canonical. I have an example similar to this, so i take q = - partial F / partial p , so i solve from the original equation of Q = p + iaq, i solve for q and then take the integral and solve for F.
 
Would the hamiltonian of a harmonic oscillator be H = p2/2 +(1/2)kx2
 
sorry i meanH = p2/2m +(1/2)kx2
 
H = p2/2m +(1/2)kq2
 

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