High-fidelity quantum logic gates using trapped-ion hyperfine qubits

TL;DR

This paper reports high-fidelity laser-driven quantum logic gates using hyperfine qubits in calcium-43 ions, achieving fidelities suitable for fault-tolerant quantum computing and analyzing the speed-fidelity trade-offs.

Contribution

It demonstrates two-qubit and single-qubit gates with record fidelities in trapped ions and develops a theoretical error model to identify sources of infidelity.

Findings

Two-qubit gate fidelity of 99.9%

Single-qubit gate fidelity of 99.9934%

Identified key technical sources of infidelity

Abstract

We demonstrate laser-driven two-qubit and single-qubit logic gates with fidelities 99.9(1)% and 99.9934(3)% respectively, significantly above the approximately 99% minimum threshold level required for fault-tolerant quantum computation, using qubits stored in hyperfine ground states of calcium-43 ions held in a room-temperature trap. We study the speed/fidelity trade-off for the two-qubit gate, for gate times between 3.8$\mu$s and 520$\mu$s, and develop a theoretical error model which is consistent with the data and which allows us to identify the principal technical sources of infidelity.