arXiv:2101.11390 · PRX Quantum

Compact Ion-Trap Quantum Computing Demonstrator

Ivan Pogorelov, Thomas Feldker, Christian D. Marciniak, Lukas Postler, G. Jacob, O. Krieglsteiner, Verena Podlesnic, M. Meth, Vlad Negnevitsky, M. Stadler, Bernd Höfer, Christoph A. Wächter, Kirill Lakhmanskiy, R. Blatt, Philipp Schindler, Thomas Monz

Published Jun 17, 2021• 386 citations

arXiv HTML PDF

Abstract

Quantum information processing is steadily progressing from a purely academic discipline towards applications throughout science and industry.Transitioning from lab-based, proof-of-concept experiments to robust, integrated realizations of quantum information processing hardware is an important step in this process.However, the nature of traditional laboratory setups does not offer itself readily to scaling up system sizes or allow for applications outside of laboratory-grade environments.This transition requires overcoming challenges in engineering and integration without sacrificing the state-of-the-art performance of laboratory implementations.Here, we present a 19-inch rack quantum computing demonstrator based on 40 Ca + optical qubits in a linear Paul trap to address many of these challenges.We outline the mechanical, optical, and electrical subsystems.Furthermore, we describe the automation and remote access components of the quantum computing stack.We conclude by describing characterization measurements relevant to quantum computing including site-resolved single-qubit interactions, and entangling operations mediated by the Mølmer-Sørensen interaction delivered via two distinct addressing approaches.Using this setup, we produce maximally entangled Greenberger-Horne-Zeilinger states with up to 24 ions without the use of postselection or error mitigation techniques; on par with well-established conventional laboratory setups.

DOI: 10.1103/prxquantum.2.020343

Related papers

Trapped-Ion Quantum Computing

Albert Frisch, Alexander Erhard, Thomas Feldker +12 more

Abstract The future of quantum information processing requires a stable hardware platform to execute quantum circuits reliably and with low error rates, such that solutions for industrial applications can be built on top of it. Trapped-ion quantum computing, among other platforms, currently proves to be very suitable for the transition from tabletop, lab-based experiments to rack-mounted, on-premise systems which allow operation in data center environments. Several technical challenges need to be solved and controlling many degrees of freedom needs to be optimized and automated, before industrial applications can be successfully implemented on quantum computers situated within data centers. These necessary developments range from the architecture of an ion trap that fundamentally defines the supported instruction sets, over the control electronics and laser systems, which limit the quality of qubit operations, to the optimized compilation of quantum circuits based on qubit properties and gate fidelities. In this chapter, we give an introduction to the ion-trap quantum computing platform, present the current technical state of the art of Alpine Quantum Technologies’ ion-trapping hardware and rack-based quantum computing systems, and highlight parts of the execution stack.

Springer eBooksJan 1, 20242 citations

Quantum error correction in a compact ion-trap quantum computer

Pogorelov, Ivan

The field of quantum computing has been developing rapidly over the last decades, driven by the belief that quantum computing can provide computational advantage over devices of other computational paradigms. However, the aspect of scaling quantum computing hardware systems to sizes where computational advantage can be achieved remains the cornerstone problem of the field. This thesis constitutes a step in the path towards scalable quantum systems. Specifically, the thesis describes the commissioning and operation of a trapped-ion quantum computing setup with modular design assembled in two 19-inch racks. The setup functions as a standalone device without a need for any special external infrastructure. The setup is capable of operating with 16 qubits in a highly-automated way with the ability to access the setup through a hardware-agnostic high-level interface. Details required for working with a 16-ion chain and the prospects of scaling the system further are discussed throughout the work. The setup's performance is demonstrated via experimental implementation of quantum error correction, a major milestone on the way to scalable and practically-useful quantum computing. Various quantum error correction primitives were performed with logical qubits encoded using color codes. The primitives include encoding of the logical states, direct implementation of logical Clifford gates, and implementation of logical non-Clifford gates via magic state injection and code switching. These results represent one of the first experimental logical-level manipulations with encoded qubits.

Jan 1, 20250 citations

Robust Quantum Control & Verification & Quantum Simulation with Trapped Ions

Harrison Ball

This PhD thesis reports on the development of a wide variety of theoretical and experimental capabilities in the field of quantum information processing using trapped ions. The presentation is organized in two distinct parts. The first part presents a series of published articles containing theoretical results, and their experimental validation, advancing a range of tools and techniques in error-resilient quantum control and robust verification procedures. One of the fundamental challenges in realizing a general purpose quantum computer is the management of error in fragile quantum systems. A familiar aspect of this challenge is decoherence, a process by which the system looses its stored quantum information, rendering it useless for subsequent computation. This collection of works focuses on reducing sources of quantum decoherence and precisely quantifying residual errors in real quantum systems dominated by realistic temporally-correlated noise processes, of central importance in any future architecture for quantum computing. The second part focuses on the design, construction and characterization of a complex experimental system capable of supporting a broad calls of quantum simulation experiments with hundreds of spin qubits using 9Be+ ions in a Penning trap. The trap design is optimized to suppress non-harmonic trapping potentials while providing wide optical access for engineering enhanced spin-motion coupling across large ion crystals. A superconducting magnet, equipped with a fully closed-cycle dual LN2/LHe recondensor, provides the magnetic field for trapping and produces the 55-GHz Zeeman-split qubit states suitable for microwave control. A custom UV laser system for driving the relevant transitions in neutral and ionized beryllium, as well as UV-compatible fibers and in-bore optomechanics for delivering microwave and laser beams to the trap, is presented. The thesis concludes with a brief outlook towards future theoretical and experimental studies, and extensions of the experimental setup

Feb 21, 20180 citations

Trapped-ion quantum computing: Progress and challenges

Colin Bruzewicz, John Chiaverini, Robert McConnell +1 more

Trapped ions are among the most promising systems for practical quantum computing (QC). The basic requirements for universal QC have all been demonstrated with ions, and quantum algorithms using few-ion-qubit systems have been implemented. We review the state of the field, covering the basics of how trapped ions are used for QC and their strengths and limitations as qubits. In addition, we discuss what is being done, and what may be required, to increase the scale of trapped ion quantum computers while mitigating decoherence and control errors. Finally, we explore the outlook for trapped-ion QC. In particular, we discuss near-term applications, considerations impacting the design of future systems of trapped ions, and experiments and demonstrations that may further inform these considerations.

arXiv:1904.04178Applied Physics ReviewsMay 29, 20191,478 citations

Integrated optical approach to trapped ion quantum computation

Jungsang Kim, C. Kim

Recent experimental progress in quantum information processing with trapped ions have demonstrated most of the fundamental elements required to realize a scalable quantum computer. The next set of challenges lie in realization of a large number of qubits and the means to prepare, manipulate and measure them, leading to error-protected qubits and fault tolerant architectures. The integration of qubits necessarily require integrated optical approach as most of these operations involve interaction with photons. In this paper, we discuss integrated optics technologies and concrete optical designs needed for the physical realization of scalable quantum computer.

arXiv:0711.3866Quantum Information and ComputationMar 1, 200952 citations

Integrated optical multi-ion quantum logic

Karan K. Mehta, Chi Zhang, Maciej Malinowski +3 more

Abstract Practical and useful quantum information processing requires substantial improvements with respect to current systems, both in the error rates of basic operations and in scale. The fundamental qualities of individual trapped-ion1 qubits are promising for long-term systems2, but the optics involved in their precise control are a barrier to scaling3. Planar-fabricated optics integrated within ion-trap devices can make such systems simultaneously more robust and parallelizable, as suggested by previous work with single ions4. Here we use scalable optics co-fabricated with a surface-electrode ion trap to achieve high-fidelity multi-ion quantum logic gates, which are often the limiting elements in building up the precise, large-scale entanglement that is essential to quantum computation. Light is efficiently delivered to a trap chip in a cryogenic environment via direct fibre coupling on multiple channels, eliminating the need for beam alignment into vacuum systems and cryostats and lending robustness to vibrations and beam-pointing drifts. This allows us to perform ground-state laser cooling of ion motion and to implement gates generating two-ion entangled states with fidelities greater than 99.3(2) per cent. This work demonstrates hardware that reduces noise and drifts in sensitive quantum logic, and simultaneously offers a route to practical parallelization for high-fidelity quantum processors5. Similar devices may also find applications in atom- and ion-based quantum sensing and timekeeping6.

Jan 1, 2020249 citations