Exercise: Verify that the number-of-phonons operator N, defined by Eq. (6.62), commutes with a product of creation and destruction operators if and only if the number of a's equals the number of a's in the product.
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First, let's recall the definition of the number-of-phonons operator N. According to Eq. (6.62), it is given by: N = a†a where a† is the creation operator and a is the destruction operator. Show more…
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