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In this problem, we are given the following quantum mechanical state.
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Ψ equal to 1 over root 2 state 1 plus i times state 2.
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And these states belong to the simple harmonic oscillator.
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So these are the number states.
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And with this ψ state, we are going to compute the expectation value of the position operator.
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Since we are dealing with the number states like 1, 2, 3, etc.
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It would be really beneficial if we use the creation and annihilation operators.
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So a and a dagger.
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And we remember that x can be written, can be expressed in terms of a and a dagger in this manner.
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A plus a dagger times some constant.
00:56
And we also remember how a and a dagger work.
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A acting on n will give us root n, n minus 1.
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And a dagger acting on n will give us root n plus 1 and the state n plus 1.
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So let us carry out this calculation.
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We have this expectation value.
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So on the left, we take the conjugate of the given state.
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We have 1 minus i 2 over root 2 times x.
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Omega times a plus a dagger.
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And we have the state itself over root 2.
01:46
Here we have 1 over 2 square root of h bar over 2m.
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Omega.
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Then 1 minus i 2 times...