How to determine a Limits of Integration of Wave Packet

In summary, the conversation discusses the determination of the normalization constant A for a force-free particle described by a wave packet with various intervals. The goal is to calculate the mean values and variances of the position and momentum operators. The process involves finding the integrals for each interval and using them to determine A. The conversation also includes a question about the integration limits for the first integral.
  • #1
Zaknife
12
0

Homework Statement


Consider a force-free particle of mass m described, at an instant of time t = 0, by
the following wave packet:
[itex]
\begin{array}{l}
0 \ \mathrm{for} \ |x| > a + \epsilon \\
A \ \mathrm{for} \ |x| ≤ a \\
-\frac{A}{\epsilon} (x − a − \epsilon) \ \mathrm{for} \ a < x ≤ a + \epsilon \\
\frac{A}{\epsilon}(x + a + \epsilon) \ \mathrm{for} \ − a − \epsilon ≤ x < a \\
\end{array}
[/itex]
where a, ε, and a normalization constant A are all positive numbers. Calculate mean
values and variances of the position and momentum operators [itex] x , x^{2} , \sigma_{x} \ and \ p_{x}[/itex] .

Homework Equations


[itex]
1=\int_{-\infty}^{\infty} |\psi(x,t)|^{2}
[/itex]

The Attempt at a Solution


I want to determine normalization constant A. I don't know what kind of integration limits i should use for the case:
[itex] A \ \mathrm{for} \ |x| ≤ a [/itex].
Do you have any ideas ? Thanks in advance !
 
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  • #2
You have a lot of intervals and need to use the fact that the integral will be a sum of integrals for each interval. So write all the integrals, compute them all the find A. Then compute all other items.
 
  • #3
Ok , so far i have:
[itex]\int_{??}^{??} A^{2} dx (?) -\frac{A^{2}}{\epsilon^{2}}\int_{a}^{a+\epsilon} (x-a-\epsilon)^{2} dx +\frac{A^{2}}{\epsilon^{2}}\int_{-a-\epsilon}^{a} (x+a+\epsilon)^{2} dx =1.[/itex] My question is what are the integration limits for the first integral ?
 
  • #4
Where did you pick the first one from ? Is there an interval where the wavefunction is 1 ?
 
  • #5
So, should i include first integral ? That was my problem/question ?
 

1. How do you determine the limits of integration for a wave packet?

The limits of integration for a wave packet can be determined by considering the physical parameters of the system, such as the size and shape of the wave packet, the energy of the particles involved, and the potential energy of the system. These parameters can be used to define the boundaries of the wave packet and determine the appropriate limits of integration.

2. What is the significance of determining the limits of integration for a wave packet?

The limits of integration for a wave packet are important because they define the boundaries within which the wave function is valid. This allows us to accurately calculate the properties of the wave packet and understand its behavior within a given system.

3. Can the limits of integration for a wave packet change over time?

Yes, the limits of integration for a wave packet can change over time, especially if the system is dynamic or if the wave packet interacts with other particles or fields. This change in limits can affect the behavior and properties of the wave packet.

4. How can experimental data be used to determine the limits of integration for a wave packet?

Experimental data can be used to determine the limits of integration for a wave packet by analyzing the behavior and properties of the wave packet as it interacts with the system. By observing the changes in the wave packet over time, we can infer the appropriate limits of integration for that particular system.

5. Are there any mathematical equations or models that can help determine the limits of integration for a wave packet?

Yes, there are mathematical equations and models, such as the Schrödinger equation, that can be used to determine the limits of integration for a wave packet. These equations take into account the physical parameters of the system and can accurately predict the behavior and properties of the wave packet within the given limits of integration.

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