BQA: A High-performance Quantum Circuits Scheduling Strategy Based on Heuristic Search

TL;DR

This paper introduces BQA, a heuristic-based quantum circuit scheduling strategy that optimizes swap gate insertion to reduce execution time and error rates, outperforming existing methods like Qiskit especially in complex circuits.

Contribution

The paper proposes a novel heuristic scheduling method, BQA, that intelligently inserts swap gates to minimize overhead and improve quantum circuit execution efficiency.

Findings

BQA reduces execution time to half of Qiskit's for optimized circuits.

BQA performs better with circuits having many two-qubit gates.

The method lowers decoherence error rates by optimizing swap gate placement.

Abstract

Currently, quantum computing is developing at a high speed because its high parallelism and high computing power bring new solutions to many fields. However, due to chip process technology, it is difficult to achieve full coupling of all qubits on a quantum chip, so when compiling a quantum circuit onto a physical chip, it is necessary to ensure that the two-qubit gate acts on a pair of coupled qubits by inserting swap gates. It will cause great additional cost when a large number of swap gates are inserted, leading to the execution time of quantum circuits longer. In this paper, we designed a way based on the business to insert swap gates BQA(Busy Qubits Avoid). We exploit the imbalance of the number of gates on qubits, trying to hide the overhead of swap gates. At the same time, we also expect swap gates to make as little negative impact on subsequent two-qubit gates as possible. We have designed a heuristic function that can take into account both of these points. Compared with qiskit, the execution time of the circuit optimized by our proposed method is only 0.5 times that of the qiskit compiled circuit. And when the number of two-qubit gates is large, it will achieve higher level than general conditions. This implies higher execution efficiency and lower decoherence error rate.