Quantum Circuit Pruning: Improving Fidelity via Compilation-Aware Circuit Approximation

TL;DR

This paper introduces a routing-aware pruning technique for quantum circuits on NISQ devices that selectively removes low-impact gates to enhance fidelity and reduce gate counts, considering compilation overhead.

Contribution

It proposes a novel circuit pruning strategy that accounts for routing costs, improving fidelity and reducing gate counts in quantum circuit compilation.

Findings

Reduces two-qubit gate counts by up to 48.6%.

Improves final state fidelity by up to 47.7%.

Effective especially for larger circuits with high routing overhead.

Abstract

This work presents a routing-aware pruning strategy for quantum circuits executed on Noisy Intermediate-Scale Quantum (NISQ) devices. We propose a method to remove parametric controlled rotations whose small rotation angles do not justify the routing overhead required for their implementation. By selectively pruning such gates, the method mitigates fidelity loss arising from additional SWAP operations introduced during compilation. Our approach evaluates whether executing a gate leads to greater fidelity loss than omitting it. Simulations on benchmark circuits with realistic noise models show that the method reduces two-qubit gate counts (up to 48.6%) while improving final state fidelity (up to 47.7%), especially for larger circuits where routing costs dominate.