- #1
arpon
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Suppose, the energy of a particle is measured, say ##E_1##. So now the state vector of the particle is the energy eigenket ##|E_1>##.
Then the position of the particle is measured, say ##x##. As the Hamiltonian operator and the position operator are non-commutative, the state vector is changed to the position eigenket ##|x>## which is different from ##|E_1>##.
Now the energy is measured again. As the state vector is no longer ##|E_1>##, it is not guaranteed that the energy is still ##E_1## as the first measurement.
Does the measurement change the amount of energy of the system? How doesn't this violate the law of energy conservation?
Then the position of the particle is measured, say ##x##. As the Hamiltonian operator and the position operator are non-commutative, the state vector is changed to the position eigenket ##|x>## which is different from ##|E_1>##.
Now the energy is measured again. As the state vector is no longer ##|E_1>##, it is not guaranteed that the energy is still ##E_1## as the first measurement.
Does the measurement change the amount of energy of the system? How doesn't this violate the law of energy conservation?