Finding the operators for time derivatives of observables

In summary, the conversation discusses the relationship between the time derivative of an operator and the operator representing the time derivative of an observable in the quantum harmonic oscillator. It is suggested that finding the momentum operator matrix is simply taking the time derivative of the position matrix and multiplying it by the mass. However, it is noted that this result is too simple and a more detailed explanation can be found in an elementary way in the provided link.
  • #1
snoopies622
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Looking through this matrix approach to the quantum harmonic oscillator,

http://blogs.physics.unsw.edu.au/jcb/wp-content/uploads/2011/08/Oscillator.pdf

especially the equations

[tex]

m \hat{ \ddot { x } } = \hat { \dot {p} } = \frac {i}{\hbar} [ \hat {H} , \hat {p} ]

[/tex]

I'm getting the impression that there's no difference between the time derivative of an operator (of an observable) and the operator representing the time derivative of that observable. That is, between [tex]

\dot { \hat {x } }

[/tex]and[tex]

\hat { \dot {x} }[/tex] Is this true? If so it would mean that, once I knew the position operator matrix for a one-particle system, finding the momentum operator matrix would be simply taking the time derivative of the position matrix (replacing every element of the matrix with its time derivative) and multiplying the whole thing by the mass.

Something tells me that that's too easy and this is just a notation problem in this particular essay, but then I'm new to matrix mechanics.
 
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  • #2

Related to Finding the operators for time derivatives of observables

1. What are operators for time derivatives of observables?

Operators for time derivatives of observables are mathematical representations of physical quantities that can be measured over time. They are used in quantum mechanics to calculate the rate of change of an observable, such as position or momentum, over time.

2. Why do we need operators for time derivatives of observables?

Operators for time derivatives of observables are essential in quantum mechanics because they help us to understand the behavior of physical systems and make predictions about their future states. They also allow us to calculate the average value of an observable over time.

3. How do you find the operators for time derivatives of observables?

The operators for time derivatives of observables can be found using the Heisenberg equation of motion, which relates the time derivative of an observable to its commutator with the Hamiltonian operator. The resulting operator is known as the Heisenberg operator.

4. Are the operators for time derivatives of observables unique?

Yes, the operators for time derivatives of observables are unique for a given system. This is because they are determined by the specific Hamiltonian operator that describes the system. However, different systems may have different operators for the same observable due to variations in their Hamiltonians.

5. How are operators for time derivatives of observables used in experiments?

Operators for time derivatives of observables are used in experiments to make predictions about the behavior of quantum systems. By measuring the rate of change of an observable over time, scientists can verify the accuracy of these predictions and gain a better understanding of the underlying physical principles at play.

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