Scaling the neutral atom Rydberg gate quantum computer by collective encoding in Holmium atoms

TL;DR

This paper proposes a scalable approach for neutral atom Rydberg gate quantum computers using collective encoding in Holmium atoms, enabling large, fully connected qubit registers with high fidelity.

Contribution

It introduces a novel collective encoding method in Holmium atoms to significantly increase the number of qubits in neutral atom quantum processors.

Findings

Approximately 500 qubits can be directly connected in 2D with low error rates.

A 60-qubit collective register in Holmium is feasible and detailed.

A design for a 1000-qubit fully connected quantum processor is proposed.

Abstract

We discuss a method for scaling a neutral atom Rydberg gate quantum processor to a large number of qubits. Limits are derived showing that the number of qubits that can be directly connected by entangling gates with errors at the $10^{-3}$ level using long range Rydberg interactions between sites in an optical lattice, without mechanical motion or swap chains, is about 500 in two dimensions and 7500 in three dimensions. A scaling factor of 60 at a smaller number of sites can be obtained using collective register encoding in the hyperfine ground states of the rare earth atom Holmium. We present a detailed analysis of operation of the 60 qubit register in Holmium. Combining a lattice of multi-qubit ensembles with collective encoding results in a feasible design for a 1000 qubit fully connected quantum processor.