Oral: Optimizing Quantum Circuits Consisting of Millions of Gates*

Quantum circuit optimization is a hard problem and at the same time necessary for executing real quantum computations. In order to become practical, quantum circuit optimization has to reach the performance of classic VLSI logic synthesis. Various heuristic-based methods have been proposed to tackle quantum circuit optimisation, but none seems to be applicable to large-scale circuits. Herein, we bridge the performance gap and present a method and the tools for optimizing very large-scale quantum circuits. We exploit the efficiency of Relational Database Management Systems and perform thousands of quantum circuit optimization steps per second. We benchmark our method on both synthetic and practical circuits, including quantum signal processing, and show numerical evidence of its speed and scalability. We expect for our method to be an integral part of the next generation quantum software.