Long-ranged gates in quantum computation architectures with limited connectivity

TL;DR

This paper presents a scalable quantum computing architecture using limited connectivity, enabling efficient long-range entanglement and parallel two-qubit gates with minimal overhead, suitable for current superconducting systems.

Contribution

It introduces a novel architecture that combines data and entanglement qubits to generate long-range entanglement efficiently with minimal circuit rounds.

Findings

Achieves $O(\sqrt n)$ simultaneous long-range two-qubit gates.

Requires only one round of nearest-neighbor gates and mid-circuit measurements.

Applicable to existing superconducting quantum architectures with constant overhead.

Abstract

We propose a quantum computation architecture based on geometries with nearest-neighbor interactions, including e.g. planar structures. We show how to efficiently split the role of qubits into data and entanglement-generation qubits. Multipartite entangled states, e.g. 2D cluster states, are generated among the latter, and flexibly transformed via mid-circuit measurements to multiple, long-ranged Bell states, which are used to perform several two-qubit gates in parallel on data qubits. We introduce planar architectures with $n$ data and $n$ auxiliary qubits that allow one to perform $O(\sqrt n)$ long-ranged two-qubit gates simultaneously, with only one round of nearest neighbor gates and one round of mid-circuit measurements. We also show that our approach is applicable in existing superconducting quantum computation architectures, with only a constant overhead.