Where can I find detailed description of cononical quantization?

In summary, the usual quantization procedure is to quantize it in x, y, z coordinate system, then change it to the spherical coordinate system, and then identify the part relating to r is -\frac{\hbar^2}{2m}\frac{1}{r}\frac{\partial^2}{\partial r^2}r.
  • #1
Leamas
2
0
For example, I want to know how to quantize a free particle in the spherical coordinates. Given a classical Hamiltonian [tex]H(r, \theta, \phi, p_r, p_{\theta}, p_{\phi})[/tex], the standard procedure tells us to let [tex]r[/tex], [tex]\theta[/tex], [tex]\phi[/tex] 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 [tex]p_r=-i\hbar\frac{\partial}{\partial r}[/tex], but the expression resulting from the usual quantization procedure is [tex]p_r=-i\hbar(\frac{\partial}{\partial r}+\frac{1}{r})[/tex].

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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  • #2
what is a "usual" quantization procedure?
 
  • #3
The usual procedure is like this: first quantize it in [tex]x[/tex], [tex]y[/tex], [tex]z[/tex] coordinate system, one obtains: [tex]H=-\frac{\hbar^2}{2m}(\frac{\partial^2}{\partial x}+\frac{\partial^2}{\partial y}+\frac{\partial^2}{\partial z})[/tex]. Then change it to the spherical coordinate system, using simple calculus, one gets: [tex]H=-\frac{\hbar^2}{2m}\frac{1}{r}\frac{\partial^2}{\partial r^2}r+\frac{\bold{l}^2}{2mr^2}[/tex], with [tex]\bold{l}[/tex] the angular momentum, then one identifys the part relating to [tex]r[/tex] is [tex]-\frac{\hbar^2}{2m}\frac{1}{r}\frac{\partial^2}{\partial r^2}r[/tex], which is [tex]\frac{p_r^2}{2m}[/tex] where [tex]p_r=-i\hbar(\frac{\partial}{\partial r}+\frac{1}{r})[/tex].
 
  • #4
Why is that the usual quantization process?

Just take the laplace-operator in spherical coordinates.


Where is [tex]p_r=-i\bar{h}\frac{\partial}{\partial r}[/tex]
given in Sakurai?
 
  • #5
https://www.physicsforums.com/showthread.php?t=116577
 
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1. What is cononical quantization?

Canonical quantization is a mathematical procedure used in quantum mechanics to convert a classical field theory into a quantum field theory. It involves promoting classical fields to operators and imposing commutation relations on them.

2. Why is cononical quantization important?

Canonical quantization is important because it allows us to describe and study the behavior of quantum systems, which cannot be described using classical mechanics. It provides a way to understand the fundamental nature of particles and their interactions.

3. What is the process of cononical quantization?

The process of canonical quantization involves first identifying a classical field theory, then promoting the fields to operators and imposing commutation relations on them. This results in a quantum field theory, which can then be used to make predictions about the behavior of the system.

4. Where can I find a detailed description of cononical quantization?

A detailed description of canonical quantization can be found in many textbooks and online resources on quantum mechanics, such as "Quantum Field Theory for the Gifted Amateur" by Tom Lancaster and Stephen J. Blundell, or "Quantum Mechanics: The Theoretical Minimum" by Leonard Susskind and Art Friedman.

5. What are some applications of cononical quantization?

Canonical quantization has many applications in modern physics, such as in particle physics, condensed matter physics, and quantum gravity. It is used to describe the behavior of fundamental particles, study the properties of materials, and understand the nature of spacetime at a microscopic level.

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