Evaluation of Parameterized Quantum Circuits with Cross-Resonance Pulse-Driven Entanglers

TL;DR

This paper demonstrates that pulse-optimized parameterized quantum circuits significantly improve performance and efficiency in variational algorithms on IBM quantum hardware, especially for MaxCut and Chemistry problems.

Contribution

The paper introduces pulse-level optimization of two-qubit entanglers for VQAs, enhancing circuit efficiency and performance on near-term quantum devices.

Findings

Pulse-optimized ansatze reduce state preparation times by over 50%.

Pulse-optimized PQCs maintain expressibility comparable to standard PQCs.

Pulse-optimized PQCs outperform standard configurations on MaxCut and Chemistry problems.

Abstract

Variational Quantum Algorithms (VQAs) have emerged as a powerful class of algorithms that is highly suitable for noisy quantum devices. Therefore, investigating their design has become key in quantum computing research. Previous works have shown that choosing an effective parameterized quantum circuit (PQC) or ansatz for VQAs is crucial to their overall performance, especially on near-term devices. In this paper, we utilize pulse-level access to quantum machines and our understanding of their two-qubit interactions to optimize the design of two-qubit entanglers in a manner suitable for VQAs. Our analysis results show that pulse-optimized ansatze reduce state preparation times by more than half, maintain expressibility relative to standard PQCs, and are more trainable through local cost function analysis. Our algorithm performance results show that in three cases, our PQC configuration outperforms the base implementation. Our algorithm performance results, executed on IBM Quantum hardware, demonstrate that our pulse-optimized PQC configurations are more capable of solving MaxCut and Chemistry problems compared to a standard configuration.