What is the Normalisation Constant for an Electron in Spin State?

In summary, the conversation discusses finding the normalisation constant for an electron in the spin state, with confusion about the meaning of "in the spin state" and the concept of wave function. Through further discussion, it is determined that the normalisation constant can be found by normalizing the complex vector to unit length, resulting in A = 1/5. The conversation also delves into the concept of wave function and how it relates to the spin state.
  • #1
ZoroP
18
0
Normalisation constant~ help~~

Homework Statement



An electron is in the spin state |> = A (3i, 4), so determine the normalisation constant A.

Homework Equations



:rolleyes: :frown:

The Attempt at a Solution



:cry: Well, I get confused about this questions, can anybody tell me what the normalisation constant is in this case? And does "in the spin state" mean something for given condition? Thanks a lot.
 
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  • #2


ZoroP said:

Homework Statement



An electron is in the spin state |> = A (3i, 4), so determine the normalisation constant A.

Homework Equations



:rolleyes: :frown:

The Attempt at a Solution



:cry: Well, I get confused about this questions, can anybody tell me what the normalisation constant is in this case? And does "in the spin state" mean something for given condition? Thanks a lot.
Spin is simply a property that particles posses and this "spin state" describes, well the state of the spin of a particle or system of particles.

As for the question, what does one normally mean when one says a "normalisation constant". What does it mean in the context of a wave function for example?
 
  • #3


Well, thanks a lot, but i don't think this problem is discussing about wave function, I cannot find any concept about wave function in my lecture notes. Thus, I consider that this question is only about math and calculation. Or maybe you can teach me some about the wave function or any other ideas? Thanks any way~
 
  • #4


Do you know about complex vectors? And how to normalize those to unit length?
 
  • #5


yes, o! you mean I can just do it like A = 1/|(3i, 4)|?? Thanks!
 
  • #6


Yep, that's all there is to it. But don't forget to simplify that expression for A you got now.
 
  • #7


Thanks, so it's A = 1/5
 
  • #8


So in Physics we can write the spin state as a function of the particle:

[tex]|\psi \rangle = A \left ( \begin{array}{cc} 3i \\ 4 \end{array} \right)[/tex]

But wave function must integrate to unity over all space, so:

[tex]\langle \psi | \psi \rangle = 1 = A^2\left ( \begin{array}{cc} -3i & 4 \end{array} \right) \left ( \begin{array}{cc} 3i \\ 4 \end{array} \right) = 25A^2[/tex]

So I agree with your answer
 
  • #9


BerryBoy said:
So in Physics we can write the spin state as a function of the particle:

[tex]|\psi \rangle = A \left ( \begin{array}{cc} 3i \\ 4 \end{array} \right)[/tex]

But wave function must integrate to unity over all space, so:

[tex]\langle \psi | \psi \rangle = 1 = A^2\left ( \begin{array}{cc} -3i & 4 \end{array} \right) \left ( \begin{array}{cc} 3i \\ 4 \end{array} \right) = 25A^2[/tex]

So I agree with your answer


I friggin get it now!
 

Related to What is the Normalisation Constant for an Electron in Spin State?

What is a normalisation constant?

A normalisation constant is a mathematical term used in statistics and physics to scale a probability distribution function or wave function so that the total area under the curve is equal to 1. It is also known as a normalising constant or a normalising factor.

Why is a normalisation constant important?

A normalisation constant is important because it allows us to compare and interpret the values of a probability distribution or wave function. Without it, the total area under the curve may be greater than 1, making it difficult to determine the relative probabilities of different outcomes.

How do you calculate a normalisation constant?

A normalisation constant is calculated by dividing the original probability distribution or wave function by the total area under the curve. This ensures that the new distribution or function has a total area of 1 and can be interpreted as probabilities or amplitudes.

Can a normalisation constant be greater than 1?

Yes, a normalisation constant can be greater than 1. In fact, it is often greater than 1 in physics applications where the total probability or amplitude is distributed over infinite or continuous values. However, it is important to note that the total area under the curve must always equal 1.

What happens if a normalisation constant is not used?

If a normalisation constant is not used, the total area under the curve will not be equal to 1. This can lead to incorrect interpretations of probabilities or amplitudes and can also affect the accuracy of calculations and predictions. Therefore, it is essential to include a normalisation constant in probability distributions and wave functions.

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