Scalability of quantum computation with addressable optical lattices

TL;DR

This paper analyzes the error mechanisms, gate fidelity, and scalability of quantum computation using neutral atoms in addressable optical lattices, highlighting potential limits and achievable array sizes.

Contribution

It provides a detailed assessment of scalability limits and compares methods for single qubit gates and two-qubit interactions in optical lattice quantum computers.

Findings

3D arrays up to 100 x 100 x 100 sites may be feasible

Error rate lower bound of 1e-5 for single qubit gates in $^{133}$Cs

Parallelizability constraints limit scalability in 2D lattices

Abstract

We make a detailed analysis of error mechanisms, gate fidelity, and scalability of proposals for quantum computation with neutral atoms in addressable (large lattice constant) optical lattices. We have identified possible limits to the size of quantum computations, arising in 3D optical lattices from current limitations on the ability to perform single qubit gates in parallel and in 2D lattices from constraints on laser power. Our results suggest that 3D arrays as large as 100 x 100 x 100 sites (i.e., $\sim 10^6$ qubits) may be achievable, provided two-qubit gates can be performed with sufficiently high precision and degree of parallelizability. Parallelizability of long range interaction-based two-qubit gates is qualitatively compared to that of collisional gates. Different methods of performing single qubit gates are compared, and a lower bound of $1 \times 10^{-5}$ is determined on the error rate for the error mechanisms affecting $^{133}$Cs in a blue-detuned lattice with Raman transition-based single qubit gates, given reasonable limits on experimental parameters.