01730nas a2200145 4500008004100000245005400041210005400095260001500149490000900164520131300173100002301486700001901509700001901528856003701547 2019 eng d00aCircuit Transformations for Quantum Architectures0 aCircuit Transformations for Quantum Architectures c02/25/20190 v135 3 a
Quantum computer architectures impose restrictions on qubit interactions. We propose efficient circuit transformations that modify a given quantum circuit to fit an architecture, allowing for any initial and final mapping of circuit qubits to architecture qubits. To achieve this, we first consider the qubit movement subproblem and use the routing via matchings framework to prove tighter bounds on parallel routing. In practice, we only need to perform partial permutations, so we generalize routing via matchings to that setting. We give new routing procedures for common architecture graphs and for the generalized hierarchical product of graphs, which produces subgraphs of the Cartesian product. Secondly, for serial routing, we consider the token swapping framework and extend a 4-approximation algorithm for general graphs to support partial permutations. We apply these routing procedures to give several circuit transformations, using various heuristic qubit placement subroutines. We implement these transformations in software and compare their performance for large quantum circuits on grid and modular architectures, identifying strategies that work well in practice.
1 aChilds, Andrew, M.1 aSchoute, Eddie1 aUnsal, Cem, M. uhttps://arxiv.org/abs/1902.09102