Noisy Quantum Cellular Automata for Quantum vs Classical Excitation Transfer

Abstract

We introduce a class of noisy quantum cellular automata on a qubit lattice that includes all classical Markov chains, as well as maps where quantum coherence between sites is allowed to build up over time. We apply such a construction to the problem of excitation transfer through 1-d lattices, and compare the performance of classical and quantum dynamics with equal local transition probabilities. Our discrete approach has the merits of stripping down the complications of the open system dynamics, of clearly isolating coherent effects, of allowing for an exact treatment of conditional dynamics, all while capturing a rich variety of dynamical behaviours.