Scott Mionis, Franz Franchetti and J. Larkin (Proc. Supercomputing (SC), 2020)
Quantum Circuit Optimization with SPIRAL: A First Look
Published paper (link to publisher)
Bibtex

Compilation and optimization of quantum circuits is an integral part of the quantum computing toolchain. In many Noisy Intermediate-Scale Quantum (NISQ) devices, only loose connectivity between qubits is maintained, meaning a valid quantum circuit often requires swapping physical qubits in order to satisfy adjacency requirements. Optimizing circuits to minimize such swaps, as well as additional metrics like gate count and circuit depth, is imperative towards utilizing the quantum hardware of both today and the near future. In this work, we leverage SPIRAL, a code generation system for linear transforms built on GAPís computer algebra system, and present an application of such a system towards optimizing quantum circuits. SPIRAL natively understands tensor products, complex matrices and symbolic matrices, and the proven decomposition and rewriting capabilities are uniquely predisposed to optimize quantum circuits. Specifically, by defining the optimization problem in terms of SPIRALís breakdown and rewriting system, we construct a search problem that can be solved with techniquies like dynamic programming. The optimal circuit can then translated to QASM code, where it is executable on a real quantum device. We demonstrate that the power of SPIRAL could provide a valuable tool for future software frameworks.

Keywords:
Optimizing, SPIRAL, Quantum circuit, Quantum, Future quantum frameworks