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Tryin to do Q1 in http://members.iinet.net.au/~housewrk/QM/AQM2006.ex.newnotation.pdf [Broken] and im having trouble in b.) i get the commutator equal to

c * permutation tensor (sigma . p * (xi pk) -xi pk * sigma . p) and i know im missing some cruical step to recombine this, ie i assume the momentum operator and the sigma matrices commute but the position and momentum operators dont? furthermore i can't see how to substitute in for the position operator, do we use the alternative representation for H as i hbar d/dt ?

Hope that made sense ><

Cheers

-G

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# Homework Help: Quantum mechanics commutators

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