Commutator Relations: [x,p]=ih, Proof of p=-iħ∂/∂x+f(x)

In summary, the conversation discusses the task of showing that if x=x, the momentum operator has the representation p=-iħ∂/∂x+f(x) in the coordinate representation of the Hilbert space L^{2}(\mathbb{R},dx). This involves proving that the most general representation of the momentum operator is given by the spectral equation \hat{x}|\psi>=x|\psi>.
  • #1
alisa
3
0
given that [x,p]=ih, show that if x=x, p has the representation p=-iħ∂/∂x+f(x) where f(x) is an arbitrary function of x
 
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  • #2
alisa, you're supposed to show an attempted solution at the problem. That goes for your other threads as well.

alisa said:
given that [x,p]=ih, show that if x=x,

What do you mean " if x=x". x=x by definition.
 
  • #3
Tom Mattson said:
What do you mean " if x=x". x=x by definition.

It's the coordinate representation in which the Hilbert space is [itex] L^{2}(\mathbb{R},dx) [/itex]. The "x" operator is realized by a multiplication by "x". She's asked to prove that the most general representation of the momentum operator in this Hilbert space is the one written there.
 
  • #4
OK, so then it should read something like "If [itex]\hat{x}|\psi>=x|\psi>[/itex]...", right?
 
Last edited:
  • #5
Exactly. That's the spectral equation, but nonetheless, yes.
 

Related to Commutator Relations: [x,p]=ih, Proof of p=-iħ∂/∂x+f(x)

1. What is the significance of the commutator relation [x,p]=ih?

The commutator relation [x,p]=ih is a fundamental equation in quantum mechanics that describes the relationship between the position operator x and the momentum operator p. It states that the commutator of these two operators is equal to ih, where i is the imaginary unit and h is the reduced Planck's constant. This relation is used to derive various important principles in quantum mechanics, such as the uncertainty principle.

2. How is the commutator relation related to the proof of p=-iħ∂/∂x+f(x)?

The commutator relation [x,p]=ih is used as a starting point in the proof of the momentum operator p=-iħ∂/∂x+f(x). By applying the commutator relation to the position and momentum operators, we can derive the expression for the momentum operator in terms of the position operator and its derivative.

3. What does the symbol ħ represent in the commutator relation?

The symbol ħ, also known as h-bar, represents the reduced Planck's constant. It is a fundamental constant in quantum mechanics that relates the energy of a particle to its frequency.

4. Can the commutator relation be extended to other operators?

Yes, the commutator relation can be extended to other pairs of operators in quantum mechanics. For example, the commutator relation [A,B]=iC can be used to describe the relationship between two arbitrary operators A and B, where C is another operator.

5. How is the commutator relation used in practical applications?

The commutator relation is used in various practical applications in quantum mechanics. It is used to derive the uncertainty principle, which is a fundamental principle in quantum mechanics that states that there is a limit to the precision with which certain pairs of physical properties of a particle can be known. It is also used in the calculation of quantum mechanical observables, such as energy and momentum, in quantum systems.

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