Evaluating commutator with hamiltonian operator

spybear
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Evaluate the commutator [H,x], where H is Hamiltonian operator (including terms for kinetic and potential energy). How does it relate to p_x, momentum operator (-ih_bar d/dx)?
 
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spybear said:
Evaluate the commutator [H,x], where H is Hamiltonian operator (including terms for kinetic and potential energy). How does it relate to p_x, momentum operator (-ih_bar d/dx)?


The Hamiltoinan in a one dimensional space is defined as H=-\frac{\hbar^2}{2m}\frac{\partial^2}{\partial x^2} + V(x). So the commutator [H,x] is

[H,x]=Hx-xH=[-\frac{\hbar^2}{2m}\frac{\partial^2}{\partial x^2} + V(x)]x-x[-\frac{\hbar^2}{2m}\frac{\partial^2}{\partial x^2} + V(x)]. Continue this calculation and then by catching a glimpse of the definition of the operator p, you can get what the relation is.

AB
 
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To solve this, I first used the units to work out that a= m* a/m, i.e. t=z/λ. This would allow you to determine the time duration within an interval section by section and then add this to the previous ones to obtain the age of the respective layer. However, this would require a constant thickness per year for each interval. However, since this is most likely not the case, my next consideration was that the age must be the integral of a 1/λ(z) function, which I cannot model.
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