An End-to-End Distributed Quantum Circuit Simulator

TL;DR

This paper introduces SimDisQ, a comprehensive distributed quantum circuit simulator that models heterogeneous, noisy, and distributed quantum systems, enabling researchers to evaluate DQC architectures and optimize performance.

Contribution

It presents the first end-to-end DQC circuit simulator with novel toolkits and noise models, facilitating hardware-aware architectural exploration and benchmarking.

Findings

Heterogeneous QPUs can achieve higher fidelity with certain entanglement fidelities.

SimDisQ models noisy superconducting and trapped-ion qubits effectively.

The simulator supports integration with existing quantum software ecosystems.

Abstract

Quantum computing has made substantial progress in recent years; however, its scalability remains constrained on a monolithic quantum processing unit (QPU). Distributed quantum computing (DQC) offers a pathway by coordinating multiple QPUs to execute large-scale circuits. Yet, DQC still faces practical barriers, as its realization depends on advances in hardware-level components such as quantum transducers and high-fidelity entanglement-distribution modules. While these technologies continue to improve, mature DQC platforms remain unavailable. In the meantime, researchers need to assess the benefits of DQC and evaluate emerging DQC designs, but the software ecosystem lacks a circuit-level simulator that models heterogeneous backends, noisy connections, and distributed execution. To fill this gap, this paper proposes SimDisQ, the first end-to-end circuit-level DQC simulator, composed of a set of novel DQC-oriented automated simulation toolkits and communication noise models that can interoperate with existing toolkits in mainstream quantum software ecosystems. Leveraging circuit-level simulation capabilities, SimDisQ enables quantitative exploration of architectural design trade-offs, communication fidelity constraints, and new circuit optimization challenges introduced by DQC, providing a foundation for future research in this promising direction. Benchmarking experiments using SimDisQ respond to a couple of open questions in the community; for example, noisy simulation of superconducting and trapped-ion qubits, with a reasonable entanglement-distribution fidelity, reveal that heterogeneous QPUs can indeed yield higher execution fidelity.