A quantum computing system is typically represented by a set of non-interacting (local) two-state systems - qubits. Many physical systems can naturally have more accessible states, both local and non-local. We show that the resulting non-local network of states connecting qubits can be efficiently addressed via continuous time quantum random walks, leading to substantial speed-up of multiqubit entanglement manipulations. We discuss a three-qubit Toffoli gate and a system of superconducting qubits as an illustration.
@article{arxiv.1511.08254,
title = {Coherent modification of entanglement: benefits due to extended Hilbert space},
author = {Dmitry Solenov},
journal= {arXiv preprint arXiv:1511.08254},
year = {2017}
}