Decomposing the generalized Toffoli gate with qutrits

TL;DR

This paper introduces an efficient decomposition method for the generalized N-qubit Toffoli gate using two-qutrit gates, optimizing resource use for superconducting quantum processors with qutrit capabilities.

Contribution

The authors propose a novel decomposition scheme for multi-qubit gates utilizing two-qutrit gates, with fixed resource requirements and applicability to current superconducting quantum devices.

Findings

Decomposition scheme uses 2N-3 two-qutrit gates for N-qubit Toffoli.

Approach is compatible with existing superconducting quantum processors.

Blueprint provided for implementation on Aspen-9 platform.

Abstract

The problem of finding efficient decompositions of multi-qubit gates is of importance for quantum computing, especially, in application to existing noisy intermediate-scale quantum devices, whose resources are substantially limited. Here we propose a decomposition scheme for a generalized $N$-qubit Toffoli gate with the use of $2N-3$ two-qutrit gates for arbitrary connectivity. The fixed number of the required additional levels (the choice of qutrits is optimal) and the use of the iSWAP gate as a native operation make our approach directly applicable for ongoing experiments with superconducting quantum processors. Specifically, we present a blueprint of the realization of the proposed scheme for the Aspen-9 processor supporting quantum operations with qutrits.