Template matching-based connected constraint mapping optimization method for quantum circuits

In order to reduce the number of gates in quantum circuit to reduce the error rate running on NISQ device, it is demonstrated that the template satisfies the relevant conditions for mapping to the linear topology structure in the quantum system, and a quantum circuit connectivity constraint mapping optimization method based on template matching is proposed. This method reconstructs the templates by adding SWAP gates or replacing bridge gates to make them meet the connectivity constraints of linear topology. Aiming at the linear subcircuits in quantum circuits that satisfy the connectivity constraints of quantum topological structure, the template matching optimization method is used to replace the gates in the circuit that match the template with a few remaining unmatched gates in the template. Finally, the optimized circuit also satisfies the connectivity constraint of quantum topology. Using a set of NISQ benchmark circuits, compared with the t|ket⟩ compiler, the test results show that the number of CNOT gates can be further reduced by an average of 28.71 %, up to 40 %.