Exploring the Advantages of Layout Procedure with Fully‐Connected Quantum Computing Technologies

Abstract

Even though quantum algorithms are designed using an idealised high‐level quantum circuit description, the execution on real devices must consider the backend physical properties. Contemporary noisy intermediate‐scale quantum (NISQ) computers are characterized by limited inter‐qubit connectivity and an exclusive set of native gates, whose execution is affected by non‐negligible errors and non‐idealities. Quantum compilation, consisting of logic and layout synthesis, aims to recast the original circuit description to the target hardware by solving the coupling‐constraint and to minimize the execution time and the error rate. While a previous article addresses the first phase, the second one is the aim of this manuscript. Currently available layout tools mainly target superconducting technology. This article tries to match the unmet need for a layout synthesis library supporting a wider range of technologies. The most promising algorithms already present in the state of the art are adapted to extend the compatibility to all the supported technologies, and new approaches, which exploit the awareness of the coupling strength in fully‐connected topologies, are proposed. The integrated procedures are benchmarked against IBM's Qiskit and Cambridge Quantum Computing's compilation toolchains, and even though these strategies can be further improved, the results are encouraging.