Driven Geometric Phase Gates with Trapped Ions

TL;DR

This paper proposes a hybrid laser-microwave scheme for implementing two-qubit geometric phase gates in trapped ions, achieving low error rates and robustness against various noise sources, with simpler technical requirements than previous methods.

Contribution

It introduces a less demanding hybrid scheme for geometric phase gates in trapped ions that maintains high fidelity under realistic noise conditions.

Findings

Errors below fault-tolerance threshold achieved

Robustness against thermal, dephasing, laser-phase, and microwave-intensity noise demonstrated

Scheme simplifies experimental setup compared to previous methods

Abstract

We describe a hybrid laser-microwave scheme to implement two-qubit geometric phase gates in crystals of trapped ions. The proposed gates can attain errors below the fault-tolerance threshold in the presence of thermal, dephasing, laser-phase, and microwave-intensity noise. Moreover, our proposal is technically less demanding than previous schemes, since it does not require a laser arrangement with interferometric stability. The laser beams are tuned close to a single vibrational sideband to entangle the qubits, while strong microwave drivings provide the geometric character to the gate, and thus protect the qubits from these different sources of noise. A thorough analytic and numerical study of the performance of these gates in realistic noisy regimes is presented.