Why does Trotterization introduce error?

Question: Why can Trotterization introduce approximation error in Hamiltonian simulation? A) Because measurement always destroys all amplitudes B) Because non-commuting Hamiltonian terms cannot generally be exponentiated independently without approximation C) Because all Pauli operators commute D) Because quantum circuits cannot represent time evolution Correct: B Explanation: Trotterization approximates the exponential of a sum of Hamiltonian terms by a product of exponentials. If the terms do not commute, this product is only an approximation unless the time step is infinitesimally small. Topic: quantum computing / Hamiltonian simulation / Trotterization