Ultra-Large-Scale Compilation and Manipulation of Quantum Circuits with Pandora

Abstract: There is an enormous gap between what quantum circuit sizes can be compiled and manipulated with the current generation of quantum software and the sizes required by practical applications such as quantum chemistry or Shor's algorithm. We present Pandora, an efficient, open-source, multithreaded, high-performance-computing-enabled tool based on circuit rewrites. Pandora can be used for quantum circuit equivalence checking, full compilations of large circuits, and scalable, streaming quantum resource estimation frameworks. Pandora can easily handle billions of gates and can stream circuit partitions in resource estimation pipelines at very high rates. We utilized Pandora for full compilations of Fermi-Hubbard 100x100 and 1024-bit Shor's algorithm circuits. Compared to TKET and Qiskit, we determine a performance advantage for manipulating circuits of more than 10000 gates. For equivalence checking tasks, Pandora outperforms MQT.QCEC on specific circuits that have more than 32 qubits. The performance and versatility of Pandora open novel paths in quantum software.