I am a beginner in quantum mechanics and I am confused about the operator ΔA defined to be ΔA Ξ A - <A>. Can someone please tell me how to interpret <A>? From what I can understand, <A> is the expectation value and is defined to be <Ψ|A|Ψ>. But that is just a scalar correct? How do subtract a scalar from a matrix; do you just do the subtraction element wise from the matrix? And what does all this mean?(adsbygoogle = window.adsbygoogle || []).push({});

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# Dispersion operator in quantum mechanics

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