Quantinuum has deployed trapped-ion quantum computers based on a quantum charge-coupled (QCCD) architecture exhibiting high-fidelity operations, mid-circuit measurements, and full connectivity with record performance. Quantinuum recently released its accelerated Roadmap outlining plans to reach thousands of physical qubits while further reducing logical qubit error rates in commercial systems by 2029 [1]. Longerterm scaling of the QCCD device architecture will be enabled by replacing bulk free-space optics with integrated photonics for improved light delivery and detection. To this end, Quantinuum is developing integrated photonics technologies at the visible and ultraviolet wavelengths required for future large-scale trapped-ion quantum computers. This poster presents recent developments in materials (waveguiding materials, transparent conductive materials), visible and ultraviolet integrated photonics components for light routing and control, and the various paths to their implementation. These developments are expected to enable scaling towards larger qubit counts while reducing the physical size of the optical control systems.
The trapped-ion QCCD (quantum charge-coupled device) architecture proposal lays out a blueprint for a universal quantum computer. The design begins with electrodes patterned on a two-dimensional surface configured to trap multiple arrays of ions (or ion crystals). Communication within the ion crystal network allows for the machine to be scaled while keeping the number of ions in each crystal to a small number, thereby preserving the low error rates demonstrated in trapped-ion experiments. By proposing to communicate quantum information by moving the ions through space to interact with other distant ions, the architecture creates a quantum computer endowed with full-connectivity. However, engineering this fully-connected computer introduces a host of difficulties that have precluded the architecture from being fully realized in the twenty years since its proposal. Using a Honeywell cryogenic surface trap, we report on the integration of all necessary ingredients of the QCCD architecture into a programmable trapped-ion quantum computer. Using four and six qubit circuits, the system level performance of the processor is quantified by the fidelity of a teleported CNOT gate utilizing mid-circuit measurement and a quantum volume measurement of
26=64. By demonstrating that the low error rates achievable in small ion crystals can be successfully integrated with a scalable trap design, parallel optical delivery, and fast ion transport, the QCCD architecture is shown to be a viable path toward large quantum computers. Atomic ions provide perfectly identical, high-fidelity qubits. Our work shows that the QCCD architecture built around these qubits will provide high performance quantum computers, likely enabling important near-term demonstrations such as quantum error correction and quantum advantage.
Trapped-ion quantum computers, leveraging a quantum charge-coupled device (QCCD) architecture, have world-class performance in the field of quantum computing, offering high fidelities and all-to-all connectivity [1]. While systems have advanced over the last decade, much work remains to scale quantum computers to fault-tolerance. Providing scalable light delivery is one key challenge. Current systems utilize engineered bulk- and fiber-optic-based light delivery systems, external to the vacuum chamber, to deliver arrays of beams to ions. However, fundamental optical limitations preclude the use of such systems when scaling beyond thousands of qubits. Integrated photonic-based beam delivery offers a potential solution, with encouraging proof-of-concept demonstrations from the photonics and quantum communities [2]–[5]. Quantinuum and Sandia National Labs have partnered to accelerate the development of integrated photonics for trapped-ion quantum computing applications, working towards photonic components supporting high-fidelity operations. Here, we present development of photonic integrated components designed to deliver laser light to
Ba+qubits, utilizing a low-loss, high-confinement, trap-integrable PECVD SiN platform. In order to demonstrate two-qubit gates at 532 nm, we developed low loss, tight bend waveguides, efficient edge couplers, and asymmetric multimode interference (MMI) splitters, along with beam-forming grating out-couplers delivering gaussian beams at the ion plane. For quantum state preparation and measurement (SPAM) applications at
4 9 3 n m, we demonstrate fabrication-tolerant splitters and low-crosstalk gratings. Measured component performance shows promise for future trap-integrated demonstrations.
Atomic ions controlled by laser light are among the leading candidates for large scale quantum computing. However operational systems today require vast scaling to reach levels capable of useful computational tasks. The integration of light delivery will be an essential component of this for the trapped-ion approach. I will describe results in which the use of photonics integrated into ion trap chips has allowed us to perform high fidelity two-qubit gates, which are an essential building block for quantum computers. These systems have now been extended to the operation of multiple trap zones, and the creation of novel optical fields for ion trap control while a new generation of chips allowing integration of all required wavelengths as well as optimised light delivery offers further enhancements in performance and scaling.