Qubits’ mapping and routing for NISQ on variability of quantum gates

Abstract

Rapid development has taken place in quantum algorithms, but few of them can be implemented directly on the quantum computer because of the coupling constraint and high error rates of quantum computer operations. Transforming a circuit into an executable one on the quantum computer with the highest fidelity is an NP problem. Therefore, the algorithm tackling the mapping and routing problem of qubits is needed. Following the policy of VQA, a heuristic algorithm to solve the problem is proposed. The algorithm uses the error score derived from quantum operation’s error rate as the heuristic cost. Combining SWAP gates, physical CNOT gates, remote CNOT gates and inverse CNOT gates, the algorithm transforms the input circuit into an executable output circuit on the quantum computer with lower error score in acceptable execution time and moves forward from local optimal to global optimal.