Normalized state vector for bosons, Shankar problem

In summary, the normalized state vector for two identical bosons in states |\phi> and |\psi>, where <\phi|\psi>\neq0, would be \frac{1}{\sqrt{2(1+|<\phi|\psi>|^2)}}(|\psi\phi>+|\phi\psi>). This is obtained by using the fact that |\psi>\otimes|\phi>=|\psi\phi> and the normalization condition.
  • #1
Dahaka14
73
0

Homework Statement


Two identical bosons are found to be in states [tex]|\phi>[/tex] and [tex]|\psi>[/tex]. Write down the normalized state vector describing the system when [tex]<\phi|\psi>\neq0[/tex].

Homework Equations


The normalized state vector for two bosons with [tex]<\phi|\psi>=0[/tex], using the fact that [tex]|\psi>\otimes|\phi>=|\psi\phi>[/tex], is:
[tex]\frac{1}{\sqrt{2}}(|\psi\phi>+|\phi\psi>)[/tex].

The Attempt at a Solution


So I thought the new normalization would be to do:
[tex]1=A^{2}(<\psi\phi|+<\phi\psi|)(|\psi\phi>+|\phi\psi>)
=A^{2}(<\psi\phi|\psi\phi>+<\phi\psi|\phi\psi>
+<\psi\phi|\phi\psi>+<\phi\psi|\psi\phi>)
=A^{2}(2+C+C^{*})[/tex]
where C is a complex number. Since in general [tex]C=a+bi[/tex] where a is real and b is imaginary, [tex]C+C^{*}=(a+bi)+(a-bi)=2a[/tex]. Thus, the new, normalized state would be
[tex]\frac{1}{\sqrt{2(1+a)}}(|\psi\phi>+|\phi\psi>)[/tex]. I am not very confident with my answer, could someone please help me?
 
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  • #2
are you sure about your calculations steps not shown?

i'm not 100% sure, but would have gone something like

[tex] <\psi\phi|\psi\phi>
= (<\psi|\otimes <\phi|)(|\psi>\otimes|\phi>)
= (<\psi|\phi><\phi|\psi>)
= <\phi|\psi>^*<\phi|\psi>
= |<\phi|\psi>|^2
[/tex]
 
  • #3
That makes sense. Thanks a lot!
 

1. What is the significance of a normalized state vector for bosons in the Shankar problem?

A normalized state vector for bosons in the Shankar problem represents the probability amplitude of a specific state of the system. It ensures that the total probability of all possible states is equal to 1, as required by the principles of quantum mechanics.

2. How is the normalization condition satisfied for bosonic state vectors?

The normalization condition for bosonic state vectors is satisfied by enforcing the commutation relations of the creation and annihilation operators. This leads to a normalization factor that is dependent on the number of particles in the system and the specific state being considered.

3. Can the normalization factor for bosonic state vectors be negative?

No, the normalization factor for bosonic state vectors cannot be negative. This is because it represents a probability amplitude, which must be a positive real number. Any negative values would violate the principles of quantum mechanics.

4. How does the normalization factor change for different numbers of bosons in the system?

The normalization factor for bosonic state vectors changes depending on the number of bosons in the system. As the number of bosons increases, the normalization factor also increases, leading to a greater spread of possible states and a decrease in the probability amplitude of any individual state.

5. What happens if the normalization condition is not satisfied for a bosonic state vector?

If the normalization condition is not satisfied for a bosonic state vector, it means that the state is not physically valid. This could indicate a mathematical error or an unphysical state of the system. In order to accurately describe the system, the normalization condition must always be satisfied.

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