Is the efficiency of classical simulations of quantum dynamics related to integrability?

Efficiency of time evolution of quantum observables, and thermal states of quenched Hamiltonians, is studied using time-dependent density-matrix renormalization group method in a family of generic quantum spin chains which undergo a transition from integrable to nonintegrable-quantum chaotic case as control parameters are varied. Quantum states (observables) are represented in terms of matrix-product operators with rank D(epsilon)(t), such that evolution of a long chain is accurate within fidelity error epsilon up to time t. We found that the rank generally increases exponentially D(epsilon)(t) proportional to exp(const t), unless the model system was integrable in which case we found polynomial increase.