Normalising and Probabilities of wavefunctions

In summary, the conversation discusses normalizing a wavefunction by assuming each state is equally likely and assigning a constant 'c' to pre-multiply each state. The probability of attaining an eigenvalue ω=1 is √(2/3). One speaker initially makes a mistake in calculating the probability, but it is clarified that the correct probability is 2/3.
  • #1
Sekonda
207
0
Hey

My question is displayed below

Sc4DW.png


I think I have done this right but I wanted to check, we have to normalise the wavefunction first and I think this is done by assuming each state is equally likely and so assigning some constant 'c' to premultiply each of the 3 states.

We need multiply each state by it's Bra form such that we get 3c^{2}=1 and so c=1/√3
and provided this is correct then the probability of attaining an eigenvalue ω=1 is just

√(2/3)

Is this correct? If not what am I doing/assuming which is wrong?

Thanks,
SK
 
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  • #2
It's correct. You are not assuming that every state is equally likely, you know it from the fact that all are multiplied by the same constant (in this case 1) in the non normalized wave function.
 
  • #3
Cheers man, was thinking as I wrote that - that is was wrong... considering the question.

Thanks!
SK
 
  • #4
Don't forget to square to get the probabilities :smile:
 
  • #5
Ahh yes of course!, I did it wrong initally anyway - should of written 2/3 - giving (2/3)^(2) =4/9 as the probability, 44.4%

I believe this is correct...

Cheers!
Sk
 
  • #6
Or is this probability just 2/3? Can someone check this

Cheers!
SK
 
  • #7
The probability is 2/3. There is no need to square anything if your performed the braket.
 
  • #8
Cheers, thanks for that! Good to know i am now doing it the right way.

SK
 

FAQ: Normalising and Probabilities of wavefunctions

1. What is the purpose of normalizing a wavefunction?

Normalizing a wavefunction ensures that the total probability of finding a particle in any state is equal to 1. This allows for accurate predictions of the likelihood of a particle being in a particular state when measured.

2. How is a wavefunction normalized?

A wavefunction is normalized by dividing it by a normalization constant, which is the square root of the integral of the absolute square of the wavefunction over all space. This constant ensures that the total probability is equal to 1.

3. What is a probability density function?

A probability density function is a mathematical function that describes the likelihood of a continuous random variable taking on a certain value. In the context of wavefunctions, it represents the probability of finding a particle in a particular state.

4. How do probabilities relate to wavefunctions?

Probabilities are directly related to wavefunctions through the Born rule, which states that the probability of finding a particle in a particular state is equal to the square of the absolute value of the wavefunction at that point.

5. What is the significance of the normalization constant in wavefunctions?

The normalization constant in wavefunctions ensures that the total probability of finding a particle in any state is equal to 1. It also allows for the calculation of the average value of a physical quantity, such as position or momentum, using the wavefunction.

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