Heisenberg vs schrodinger picture

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Discussion Overview

The discussion centers on the differences and similarities between the Heisenberg and Schrödinger pictures in quantum mechanics, particularly regarding their relation to classical Hamiltonian dynamics. Participants explore the concept of "dequantization" and whether classical Hamilton's equations can be used to inform quantum mechanical solutions.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions how to work in the Heisenberg picture and whether it is possible to dequantize classical Hamilton's equations and then requantize the solutions for quantum operators.
  • Another participant challenges the notion of dequantization, asserting that quantization is a one-way process and that classical Hamiltonian equations should not be solved in a quantum context.
  • A participant expresses confusion over the textbook's emphasis on the similarity between Heisenberg's picture and classical Hamilton's equations, suggesting that this similarity does not provide practical advantages.
  • Some participants argue that all three pictures (Heisenberg, Schrödinger, and Dirac) are equivalent and useful depending on the situation, while others emphasize that the Heisenberg picture should be used consistently without relying on analogies to classical mechanics.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the utility of dequantization or the practical implications of the similarities between classical and quantum mechanics. There are competing views on the relationship between the Heisenberg picture and classical Hamiltonian dynamics.

Contextual Notes

There are unresolved assumptions regarding the applicability of classical mechanics to quantum scenarios, and the discussion reflects varying interpretations of the equivalence of different quantum mechanical frameworks.

RedX
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How does one work in the Heisenberg picture? Can you dequantize and solve the classical Hamilton's equations and somehow requantize this classical solution for the time evolution of the position and momentum operators (and more importantly the eigenvectors)? How would one go about doing that, and which is more useful, the Schrödinger picture or the Heisenberg picture or the Dirac/interaction/intermediate picture (the latter is where your frame rotates at the rate of the time-independent part of the Hamiltonian)?
 
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RedX said:
How does one work in the Heisenberg picture? Can you dequantize


What do you mean by "dequantize"??The quantization postulate goes one way only.
Are u referring to Heisenberg & Schroedinger pictures in classical dynamics...??U needn't QM to do that...

RedX said:
and solve the classical Hamilton's equations

No,u do not solve the classical Hamiltonian equations for purpose involving the word "quantum"...

RedX said:
and which is more useful, the Schrödinger picture or the Heisenberg picture or the Dirac/interaction/intermediate picture (the latter is where your frame rotates at the rate of the time-independent part of the Hamiltonian)?

Depends on the situation.They're all EQUIVALENT and useful in the same proportion...

Daniel.
 
It's just that my textbook makes a big fuss about the similarity of Heisenberg's picture to the classical Hamilton's equations, showing that the quantum operators obey the same differential equations as the variables in the classical picture. I was just thinking that you could replace the quantum Hamiltonian with the corresponding classical Hamiltonian (dequantize - I guess I'm inventing words), solve the classical equations for momentum and position variables, and somehow requantize these variablesto get the position and momentum operator as a function of time (hence almost all other variables). Guess I was hopeful that quantum mechanics would be easy . One wonders why the author even bothers pointing out the similarity between classical Hamilton's equations and Heisenberg's picture when you can't use that similarity to your advantage.
 
RedX said:
It's just that my textbook makes a big fuss about the similarity of Heisenberg's picture to the classical Hamilton's equations, showing that the quantum operators obey the same differential equations as the variables in the classical picture.


That's true.

RedX said:
I was just thinking that you could replace the quantum Hamiltonian with the corresponding classical Hamiltonian (dequantize - I guess I'm inventing words), solve the classical equations for momentum and position variables, and somehow requantize these variablesto get the position and momentum operator as a function of time (hence almost all other variables). Guess I was hopeful that quantum mechanics would be easy .

Nope,it doesn't work that way.It never will.

RedX said:
One wonders why the author even bothers pointing out the similarity between classical Hamilton's equations and Heisenberg's picture when you can't use that similarity to your advantage.

U can,just as long as u decide to do everything in the Heisenberg picture.Why would you need analogies?

Daniel.
 

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