Understanding Perturbation Theory and Spin in Quantum Mechanics

[1Kris]

In my quest to learn quantum mechanics I've become a little confused and I have a question.
It is "In The Feynman Lectures on Physics Volume 3, is most of the work, eg. ammonia molecule done using perturbation theory or is this method something else, not perturbation theory?"
I started to learn a little about perturbation theory elsewhere, and it seemed similar but not quite the same, so I'm a little foggy about this.

 

[nismaratwork]

In my quest to learn quantum mechanics I've become a little confused and I have a question.
It is "In The Feynman Lectures on Physics Volume 3, is most of the work, eg. ammonia molecule done using perturbation theory or is this method something else, not perturbation theory?"
I started to learn a little about perturbation theory elsewhere, and it seemed similar but not quite the same, so I'm a little foggy about this.

I'm sorry, but I'm not sure what it is that you're asking?

 

[1Kris]

In the Feynman Lectures on Physics, Volume 3, Feynman uses a an approximation of treating systems as two state systems. Is this the same as perturbation theory, or is it a different method?

 

[nismaratwork]

In the Feynman Lectures on Physics, Volume 3, Feynman uses a an approximation of treating systems as two state systems. Is this the same as perturbation theory, or is it a different method?

I think the best answer, infuriating as it may be, is "yes".
http://en.wikipedia.org/wiki/Perturbation_theory

You can see there are elements of it there, but it's not a pure treatment for the reasons you mention, I think.

 

[1Kris]

Haha thanks for that, why infuriating?

 

[nismaratwork]

Haha thanks for that, why infuriating?

Generally people finding that the answer is "yes" to a yes or no question is infuriating. I'm glad you don't! :)