Where can I find detailed description of cononical quantization?

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Discussion Overview

The discussion revolves around the process of canonical quantization, specifically focusing on quantizing a free particle in spherical coordinates. Participants explore the transition from classical Hamiltonians to quantum operators, addressing the challenges in obtaining specific matrix forms and the representation of combined variables such as angular momentum.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes the standard procedure for quantizing a free particle, noting the use of spherical coordinates and the resulting Hamiltonian.
  • Another participant questions what constitutes a "usual" quantization procedure, seeking clarification on the terminology.
  • A participant outlines their interpretation of the usual quantization process, detailing the steps from Cartesian to spherical coordinates and the identification of momentum operators.
  • Concerns are raised about the validity of the "usual" quantization process, with a request for sources that support the expressions used, particularly regarding the momentum operator.
  • A link to a related thread is provided for further reference.

Areas of Agreement / Disagreement

Participants express differing views on the "usual" quantization procedure and the correct form of momentum operators, indicating that multiple competing interpretations exist without a consensus.

Contextual Notes

Participants highlight potential ambiguities in the definitions of quantization procedures and the representation of combined variables, which may depend on specific assumptions or interpretations not fully resolved in the discussion.

Leamas
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For example, I want to know how to quantize a free particle in the spherical coordinates. Given a classical Hamiltonian H(r, \theta, \phi, p_r, p_{\theta}, p_{\phi}), the standard procedure tells us to let r, \theta, \phi be operators and they form a complete set. And The corresponding generalized momentums satisfy the well-known commutation relation. But starting from here, how can we obtain the specific matrix form in the coordinate representation? I looked this up in Sakurai's modern quantum mechanics, it seems to me that following the same reasoning there, we can get p_r=-i\hbar\frac{\partial}{\partial r}, but the expression resulting from the usual quantization procedure is p_r=-i\hbar(\frac{\partial}{\partial r}+\frac{1}{r}).

Another problem is that how to know the right form of some "combined" variables, like angular momentum, from the classical definition of those variables. The essential issue is the order of basic variables which the combined variables are made out of.

I know this is a very classical problem. But I can't find detailed presentation of the stuff. Does anyone know any textbook containing this thing? Thanks.
 
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what is a "usual" quantization procedure?
 
The usual procedure is like this: first quantize it in x, y, z coordinate system, one obtains: H=-\frac{\hbar^2}{2m}(\frac{\partial^2}{\partial x}+\frac{\partial^2}{\partial y}+\frac{\partial^2}{\partial z}). Then change it to the spherical coordinate system, using simple calculus, one gets: H=-\frac{\hbar^2}{2m}\frac{1}{r}\frac{\partial^2}{\partial r^2}r+\frac{\bold{l}^2}{2mr^2}, with \bold{l} the angular momentum, then one identifys the part relating to r is -\frac{\hbar^2}{2m}\frac{1}{r}\frac{\partial^2}{\partial r^2}r, which is \frac{p_r^2}{2m} where p_r=-i\hbar(\frac{\partial}{\partial r}+\frac{1}{r}).
 
Why is that the usual quantization process?

Just take the laplace-operator in spherical coordinates.


Where is p_r=-i\bar{h}\frac{\partial}{\partial r}
given in Sakurai?
 
https://www.physicsforums.com/showthread.php?t=116577
 
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