Creation and annihilation operator

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Discussion Overview

The discussion centers on the behavior of creation and annihilation operators in the context of the quantized field in the Schrödinger picture, specifically regarding their action on complex exponential functions.

Discussion Character

  • Technical explanation, Debate/contested

Main Points Raised

  • One participant questions whether the annihilation operator \(\hat{a}_{\textbf{p}}\) and creation operator \(\hat{a}^{\dagger}_{\textbf{p}}\) act on the complex exponentials \(e^{i\textbf{p} \cdot \textbf{x}}\) and \(e^{-i\textbf{p} \cdot \textbf{x}}\) respectively.
  • Another participant asserts that the operators do not act on these exponential functions.
  • A different participant suggests that the operators commute with the exponential factors, implying a different interpretation of their interaction.
  • One participant clarifies that the creation and annihilation operators are linear operators defined in Fock space, while the exponential functions are treated as numbers.

Areas of Agreement / Disagreement

There is disagreement among participants regarding the action of the creation and annihilation operators on the exponential functions, with multiple competing views presented.

Contextual Notes

Participants express differing interpretations of the relationship between the operators and the exponential functions, highlighting the complexity of their interactions in the context of quantum field theory.

Sebas4
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TL;DR
Does the annihilation/creation operator on the complex exponent?
Hey, I have a short question.
The quantized field in Schrödinger picture is given by:
\hat{\phi} \left(\textbf{x}\right) =\int \frac{d^{3}p}{\left(2\pi\right)^3} \frac{1}{\sqrt{\omega_{2\textbf{p}}}}\left(\hat{a}_{\textbf{p}}e^{i\textbf{p} \cdot \textbf{x}} + \hat{a}^{\dagger}_{\textbf{p}}e^{-i\textbf{p} \cdot \textbf{x}}\right)

My question is, does the the annihilation \hat{a}_{\textbf{p}} and creation \hat{a}^{\dagger}_{\textbf{p}} operator act on e^{i\textbf{p} \cdot \textbf{x}} and e^{-i\textbf{p} \cdot \textbf{x}} respectively? In other words: does the annihilation/creation operator on the complex exponent?
 
Last edited:
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Sebas4 said:
does the the annihilation a^p and creation a^p† operator act on eip⋅x and e−ip⋅x respectively?

No.
 
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Well, it does in the sense that ##a## and ##a^\dagger## commute with these factors.
 
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No, they don't. The creation and annihilation operators are linear operators defined in the Fock space. The expeonential functions are numbers; ##\vec{x}, \vec{p} \in \mathbb{R}^3##.
 

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