Optical tweezer-controlled entanglement gates with trapped ion qubits

TL;DR

This paper introduces a novel entanglement protocol using optical tweezers to control ion qubits, demonstrating a controlled Mølmer-Sørensen gate and discussing its scalability to larger systems with single-pulse operations.

Contribution

It presents a new optical tweezer-based entanglement protocol for trapped ions, including experimental demonstration and generalization to multi-controlled unitaries.

Findings

Successful demonstration of a controlled Mølmer-Sørensen gate with three ions.

Control qubit dephasing due to tweezer beam fluctuations observed.

Protocol can be extended to larger qubit systems with single-pulse operations.

Abstract

We propose an entanglement protocol where ions illuminated by optical tweezers serve as control qubits. We experimentally demonstrate this proposal with a controlled M$\o$lmer-S$\o$rensen operation on a three-ion chain, analogous to the canonical Toffoli gate. Our demonstration features cases in which the control qubit was in one of its logical basis states, and not in their superposition, due to dephasing by tweezer beam intensity fluctuations. Finally, we discuss how our protocol generalizes to a broad class of unitary operations and larger qubit systems, enabling a single-pulse implementation of $n$-controlled unitaries.