Quantum compiler boosts chiplet simulations of qubit interactions
QBX: A Compiler for 2-local Qubit Hamiltonian Simulation on Quantum Chiplets
Hardware Architecture
Summary
Simulating interactions between pairs of quantum bits (qubits) is important for many quantum computing tasks. The authors created QBX, a new compiler that makes these simulations work better when qubits are spread across multiple small quantum chips, called chiplets. QBX organizes the simulation steps to reduce communication between chiplets, which is often slow and costly. It also groups certain operations to use special communication pathways for faster processing. This results in shorter and more efficient quantum programs compared to existing compilers.
What this means in practice
- •For quantum hardware engineers: Optimize quantum simulations on chiplet-based quantum processors to reduce communication overhead and improve execution efficiency.
- •For quantum software developers: Generate efficient quantum circuits for 2-qubit interactions on modular quantum systems utilizing chiplets to scale simulations to larger sizes.
Authors
Zikun Li, Zhuoming Chen, Zhihao Jia
Abstract
2-local qubit Hamiltonian simulation, a fundamental task in quantum computing, is widely applied in various applications. This paper presents QBX, the first quantum compiler designed for 2-local qubit Hamiltonian simulation on quantum chiplet architectures. Existing general-purpose quantum compilers for chiplet architectures target quantum programs at the gate level and miss optimizations requiring high-level semantics of Hamiltonian simulation. Conversely, existing domain-specific compilers for Hamiltonian simulation are designed for monolithic architectures, and their limited scalability and inability to adapt to the heterogeneity of chiplet architectures lead to sub-optimal circuit outputs. QBX implements a scalable hierarchical approach to reduce both the amount and distance of cross-chiplet communications. It integrates the highway mechanism, a chiplet-oriented solution for efficient long-range qubit communication, to diminish cross-chiplet interaction costs. Furthermore, QBX efficiently aggregates 2-local Pauli strings into multi-target controlled gates, harnessing highways for deep optimization. Our evaluations show that QBX markedly outperforms both general-purpose and domain-specific compilers in circuit depth and operation count, while scaling to much larger 2-local Hamiltonian simulations.