From Sakurai and Napolitano 3rd edition

(5). [SN 3rd ed. (7.16)] A Hamiltonian for a system of bosons has the form H () + ve + m)' (9) em where is a constant. Prove that the number operator N = , (10) is a constant of the motion. (5). [SN 3rd ed. (7.16)] A Hamiltonian for a system of bosons has the form H () + ve + m)' (9) em where is a constant. Prove that the number operator N = , (10) is a constant of the motion