Demonstration of fault-tolerant Steane quantum error correction

Encoding information redundantly using quantum error-correcting (QEC) codes allows one to overcome the inherent sensitivity to noise in quantum computers to ultimately achieve large-scale quantum computation. The Steane QEC method involves preparing an auxiliary logical qubit of the same QEC code used for the data register. The data and auxiliary registers are then coupled with a logical CNOT gate, enabling a measurement of the auxiliary register to reveal the error syndrome. This study presents the implementation of multiple rounds of fault-tolerant Steane QEC on a trapped-ion quantum computer. Various QEC codes are employed, and the results are compared to a previous experimental approach utilizing flag qubits. Our experimental findings show improved logical fidelities for Steane QEC. This establishes experimental Steane QEC as a competitive paradigm for fault-tolerant quantum computing.Comment: 16 pages, 13 figure

A compact ion-trap quantum computing demonstrator

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 $^{40}\textrm{Ca}^+$ optical qubits in a linear Paul trap to address many of these challenges. We outline the mechanical, optical, and electrical subsystems. Further, we describe the automation and remote access components of the quantum computing stack. We conclude by describing characterization measurements relevant to digital quantum computing including entangling operations mediated by the Molmer-Sorenson interaction. Using this setup we produce maximally-entangled Greenberger-Horne-Zeilinger states with up to 24 ions without the use of post-selection or error mitigation techniques; on par with well-established conventional laboratory setups

CENTRIFUGAL FRACTIONATION OF LONG-STALKED MATERIALS

The screenless centrifugal fractionation approach is offered for the fractionation of the long-stalked agricultural materials lengthways. The screenless centrifugal fractionation device and its analytical model are described. The basic processes are specified – accelerating particles with the centrifugal disc, spreading in the annular aerodynamic channel, and assorting with the partitioning cylinders. The mathematical simulation of the particle acceleration with the centrifugal disc and the dropped particles motion in the unward airflow processes is carried out. The computer-based experiment is conducted. Paths of particles in the annular aerodynamic channel are obtained. The paths differ so greatly that it is possible to state the separating properties of the centrifugal force field and airflow combination. The recommendations on the arrangement of the partitioning cylinders are given. The simulation results imply the feasibility of assorting the long-stalked materials with the centrifugal tool at the cost of the differences in particle spreading paths in the airflow

Strategies for a practical advantage of fault-tolerant circuit design in noisy trapped-ion quantum computers

Fault-tolerant quantum error correction provides a strategy to protect information processed by aquantum computer against noise which would otherwise corrupt the data. A fault-tolerant universalquantum computer must implement a universal gate set on the logical level in order to perform arbi-trary calculations to in principle unlimited precision. In this manuscript, we characterize the recentdemonstration of a fault-tolerant universal gate set in a trapped-ion quantum computer [Postler etal. Nature 605.7911 (2022)] and identify aspects to improve the design of experimental setups toreach an advantage of logical over physical qubit operation. We show that various criteria to assessthe break-even point for fault-tolerant quantum operations are within reach for the ion trap quan-tum computing architecture under consideration. Furthermore, we analyze the influence of crosstalkin entangling gates for logical state preparation circuits. These circuits can be designed to respectfault tolerance for specific microscopic noise models. We find that an experimentally-informed de-polarizing noise model captures the essential noise dynamics of the fault-tolerant experiment thatwe consider, and crosstalk is negligible in the currently accessible regime of physical error rates. Fordeterministic Pauli state preparation, we provide a fault-tolerant unitary logical qubit initializationcircuit, which can be realized without in-sequence measurement and feed-forward of classical infor-mation. Additionally, we show that non-deterministic state preparation schemes, i.e. repeat untilsuccess, for logical Pauli and magic states perform with higher logical fidelity over their deterministiccounterparts for the current and anticipated future regime of physical error rates. Our results offerguidance on improvements of physical qubit operations and validate the experimentally-informednoise model as a tool to predict logical failure rates in quantum computing architectures based ontrapped ions

Розробка концепції класифікації метрик кібербезпеки

The development of the IT industry and computing resources allows the formation of cyberphysical social systems (CPSS), which are the integration of wireless mobile and Internet technologies and the combination of the Internet of things with the technologies of cyberphysical systems. To build protection systems, while minimizing both computing and economic costs, various sets of security profiles are used, ensuring the continuity of critical business processes. To assess/compare the level of CPSS security, various assessment methods based on a set of metrics are generally used. Security metrics are tools for providing up-to-date information about the state of the security level, cost characteristics/parameters from both the defense and attack sides. However, the choice of such sets is not always the same/understandable to the average person. This, firstly, leads to the absence of a generally accepted and unambiguous definition, which means that one system is more secure than another. Secondly, it does not take into account the signs of synergy and hybridity of modern targeted attacks. Without this knowledge, it is impossible to show that the metric measures the security level objectively. Thirdly, there is no universal formal model for all metrics that could be used for rigorous analysis. The paper explores the possibility of defining a basic formal model (classifier) for analyzing security metrics. The proposed security assessment model takes into account not only the level of secrecy of information resources, the level of provision of security services, but also allows, based on the requirements put forward, forming the necessary set of security assessment metrics, taking into account the requirements for the continuity of business processes. The average value of the provision of security services to CPSS information resources is 0.99, with an average value of the security level of information resources of 0.8Розвиток ІТ-індустрії та обчислювальних ресурсів дозволяє формувати соціокіберфізичні системи (CPSS), які є інтеграцією бездротових мобільних, Інтернет-технологій та комплексуванням Інтернет-речей з технологіями кіберфізичних систем. Для побудови систем захисту у таких системах за умов мінімізації як обчислювальних, і економічних витрат використовуються різні набори профілів безпеки, які мають забезпечувати безперервність критичних бізнес-процесів. Для оцінки/порівняння рівня безпеки CPSS, як правило, використовуються різні методики оцінки на основі сукупності набору метрик. Метрики безпеки є інструментами надання актуальної інформації про стан рівня безпеки, вартісних характеристик/параметрів як з боку захисту, так і з боку нападу. Однак вибір таких набір не завжди збігається/зрозумілий середньостатистичній людині. Це, по-перше, призводить до відсутності загальноприйнятого та однозначного визначення, яке означає, що одна система безпечніша, ніж інша. По-друге, не враховує ознак синергізму гібридності сучасних цільових атак. Без цих знань неможливо показати, що метрика справді об'єктивно вимірює рівень безпеки. По-третє, немає універсальної формальної моделі для всіх метрик, яку можна було б використовувати для суворого аналізу. У цій статті досліджується можливість визначення базової формальної моделі (класифікатора) для опису та аналізу метрик безпеки. Запропонована модель оцінки рівня захищеності враховує не лише рівень секретності інформаційних ресурсів, рівень забезпечення послуг безпеки, а й дозволяє на основі вимог, що висуваються, сформувати необхідний набір метрик оцінки безпеки, з урахуванням вимог до безперервності бізнес-процесів. Усереднене значення надання послуг безпеки інформаційним ресурсам CPSS забезпечується 0,99, за усередненого значення рівня таємності інформаційних ресурсів 0,

Demonstration of fault-tolerant Steane quantum error correction

<p>Source data underlying the graphical representations used in the figures and corresponding executed quantum circuits.</p&gt

Demonstration of fault-tolerant universal quantum gate operations

Quantum computers can be protected from noise by encoding the logical quantum information redundantly into multiple qubits using error correcting codes. When manipulating the logical quantum states, it is imperative that errors caused by imperfect operations do not spread uncontrollably through the quantum register. This requires that all operations on the quantum register obey a fault-tolerant circuit design which, in general, increases the complexity of the implementation. Here, we demonstrate a fault-tolerant universal set of gates on two logical qubits in a trapped-ion quantum computer. In particular, we make use of the recently introduced paradigm of flag fault tolerance, where the absence or presence of dangerous errors is heralded by usage of few ancillary 'flag' qubits. We perform a logical two-qubit CNOT-gate between two instances of the seven qubit color code, and we also fault-tolerantly prepare a logical magic state. We then realize a fault-tolerant logical T-gate by injecting the magic state via teleportation from one logical qubit onto the other. We observe the hallmark feature of fault tolerance, a superior performance compared to a non-fault-tolerant implementation. In combination with recently demonstrated repeated quantum error correction cycles these results open the door to error-corrected universal quantum computation.Comment: v3 with updated acknowledgements, 14 pages, 7 figure